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~i~p9~11s qf se99lClqrJ orif~U
Altbough thts thepound319 is noncernecl JIflinly 1111 th middotthe
prilnary ore and gangue minerals of the Zoehan ora-bodies
the ~Jeeondarr minerals aasaejated iih thG or-on are lt1113shy
cusa0(l brie-ily
Many of the nscom1axY minerrtlt3 htve not boen OhfH~rvf)d
by the prargerrt Buthor but were roconletl by Pcitert1 111 G
clehailed review of TaGmnn1~_n TJiineralf1 (1910) Tlre majority
Af middotPatmiddotmiddot t ~ l1Ogtnt~ hA 0 Vlt -~ ~ bo-1 ~ middotmiddot t bt 11~L 1 ~ ~J__ tJ AJ-bull l~ltb- b t fl1 (~L ~ t- Clil J~ ~jI C~v VIlLL 0 J V
tttera ttre i30mo eXflJnplea whioh may be open to douht In the
abH~Hlee of 8emplG~J of tho rninergls in quentl-oot ljttlf~ CSln
he slt1d on t~(J vnli dL ty of jhtJse tchmtificfItJons
AK1le q imiddotmiddot e bltOe sa tJ~ci1 P0 4shylo
AoCording to rOLorts by Waller (19(3) and Twelvetrees
anc1Rar~ (1910) anplltwi te Wt)U found in the oxidized zone
of both the enGt find west lo(les oftlC ufHllmi te (ari tmmia
f t ) middot~1J 1l X _c 1e bull
Petteld (1910) quotEHl ~ conmvnicaticm fI~()m 1 K Ward
stating that nJ1g1e~tte h8c1 been found in this 10coJ1 t ns
fclear colourless tahultll erY~3tals up to 2 inelen in
length fJfldl-tneh in (1 epth~n bull
Annaberf~i te u middot131 ll13~SO4 ) 2middot8H20
The only report of armalHrrite inihe Zoehall aren io
hnt of WilliEUTItJ (1958) wto idontLfied It aB a middott1~in co[~tin
tluo 1() fJxidation on two speeiJiH9111 of nickel ore from~he
C(Hltral Balstrup [Tine
e I bull
Atacamite Cu (OH) Cl _ _u I bull t 2 3
middotPet~-t (otc~1Cj) TYntll hltltmiddot ltmiddotl itmiddot (~ ~ in~ ~clmiddotl f - - 0 X~~ Cmiddot~ ~_ f cttfVlloll~lJ - -~ ~ vtmiddotfL gJ
smal1smounts in ffFlixed oxtdtzec1 ore in middot~l Z~middotehan queen
lI0IJringo
Azurite eu] (Of0 2 COJ )2lIIl- It t
Copper (HJrbonates lSltlamp not (HimrrtOn in the ~ieehnn area
and have teen reported in the workingn of only tlffO mlntH13
~ lt-1 ] ~middotte m Q middotd poundfelllY t 111 bullbull11) cOmiddot tA till) Qh 1 ltV ziit OL_ V~~ i1 gt~-~j(A~ tltJr~ ri4O lW -J ~Vfoj~ J_ i ~JVAlJL ~ A~
110 rlringe bull rshy
Jal1er (1903) described ft lode f~wuth-weHt of the main
emiddotil J- middott-()knimiddot~ ~OtCtmiddottmiddot J) f middot~lmiddotmiddot middottmiddot emiddottmiddot~middot)It q~) V ~~ VI ~~lt l W bullbullbull 1~~bull ~~9 Il~JQ gt _Kl o~ ~lt~V 1 t C~ 1 2 J~Q
and ofman ch lltrLIned 111 cOtiJJ-er clrlI OIlfde but lt1d
nrrt Bl~~CLfy lJllhether the c~rbmnte waD aZlLrtte oX maJachi te
or 1Joth
h) 176-r )7)middot + f) n-tr1middotl-A ~1--~middotl-1middot1i~middotlAn (Vrl ~ - -~ ol-~C _ of J~_1t ~o(gtn~1lA-Q i~L- f ~-thI~i
frOD 1Ia-heymiddots Trilndiecwl1tcdns 9Ztui to in f1pound~sociation with
maJachi to eovellito and chaleocite
PetterrJ (1910) included Zerclhan in a list of the occur-
TeuroHlCltlHl of azurite in ~r~lI3tNln5at but dHI not fJttlhc art
ipeotf~JC loelttZI at ZeeJ1an
1)bmiddot ~bmiddotmiddot 0 ( ~ J)U )B5ndhetJltiite 2 J _ IlI-ltlI~ 2 6 1
l (1 0 10) t d~
11o -l 1 f hI ltIf It~PV-VlIIl rtilj 0 to )rt I)~Ll~ F u ~ ~JOJ1J ~ 0) Il Jl1tl IfUo 4- ilT~tli
ltonUftryftor ttplcos ore in the Intolog fi(ltji~ of w~ster-n
TiStsmanl~ltLPGt1jeTd recorded that b1n(lheimi to occurred in the
bull 111 If middot0 middot~middothmiddotmiddot ~ 1 ( ~h ) U n ~ la)lmiddotJzel ZvlH9 ~ 02_Jer O(hLtlre iI~
11l~ 11l1 Ifmiddotjl~o1) - 0Jt~~ltr~J3 nAnlr oe u CJllI 1middot)~ 1 C-lgtrmiddot1Q ~fi ~~-t -emiddotmiddot t ~~l~~) -J Ltrbull_6)lt~l - A Min
(ManglM1ose Hill) tlli3 was prnbabll l~rgelymiddot blnclhettitab-ut
may also have contgjiJodmassicot a )rellow lerld QXi0G
whteh occurred In EOm~) of middottth~ ~~oehan mines
( 1 - V v_ ~ gt frt~k 1ltbull Apound1Jl
lfIol I _110shy
0 (CerargyI1te wgSEtn iJIiportCtll1t c01lstlttlerrt 1ev~ral
poundITGJltifr)toua toaaan fonnationfJ in the Zeehan field bull Reshy
pOttZ4 indicatmiddote1hal tH1fH9 occurred majnl~r in the centrmiddotnl
ancl eef5ternnrta of tho field -Etnd the localLties include
middotmiddot~1 Jlt Q 1 - 110 h J bull tmiddotmiddotmiddot middotClmiddotmiddotmiddot1 t t tJvesv~ll I)I~lY jmiddot()reuroh1Cetmiddotnf4-(~~ Hie middotItnbull )0 Su IlP s anu
ZecllUl jlleon minea am ibe nChloride- Loje tf in th(~ Colonel
North ctrea
The halHle wnso(~cant(nlally reporfod to 1)0 t e hr-onian
v ~Y omiddotr c rll 4middot ~ middotx ~~ol-41r 1 1 I tlt J ~- 84 ry I E It~ nn as elmiddot e 1 cbullbullbull_ ic variety was
01 middottmiddot1 ~ I~l ~ ~rIeuroJcoJded Co v ~i t -tr~~ ~l rJ J t ~ t~ t JUtH~tt01l 1]~1d l~efgthan2Oeen mtnes
and near Balwtrtlpa Mine
Namiddottive ~lilver vrasoften 9sr1oci~)teurod wjih the ba-Jives in
middothbcoc ossnn fOrmt1tioufl and ~]jlvetmiddot aatJDlS up to 2000 ozs
per ton ViJere recotlmiddotd
( -ltt1middot$0 P1--C0 0 3 a -_~
CeroB21ite WHoS leporta(t to be a cormtlturmt of the ltrx
idizad zone of Joverul orc-Dor1irfl in tho ochan areflshy
r ~t middotlgt crmiddot1(lt~ (ccgtgt lj lgtv ~lmiddottmiddotP 1t-J-g middot1middot11lt~(I shytlet+Al ~-H~1 (J (1(10 1) AOmiddotmiddot)J oh GO- t lt middott11tojmiddot ~ trtlto ~I $ fllll~J t ~AtOfJ li$
fllirly large quantities E~t the Silver Zeehall)rueen
S~71VBst~~r Austr~l nnd other mine at Zeehall It T111es
Jmiddot t r~rmiddottlgtrl o~tuttmiddot 1 1middot1middotmiddot c~ lcn]emiddot+_lmiddottC(1n91) c-~d i~ E~~~I (19)dJ 11J~]J ~Imiddott 1011 tlgt~iVkj~ 1ljJ ~t Dmiddot47 bull 1lt1 uL IJ~ ~
~il le ([ g~~ 1ltgt0 p 1middot1)~-J~ I i~~A-tll ~l-f1l G l1J - bull
S130e1men no 22169 frOl1 the IaBmania11 tiJuseum 001100shy
tion labelled 1~endh111tte ~1ilver (Zeehan) Qneen JUne
229
Z(~ehnntl has been identiied fUl (Hrussll~e l)y meaYlE of X-ray
dliffrnoM on
( rmiddotmiddot 11middot-l e SOfO ()~~-~_~~ ( 4
oco)r111 t1 to Pertterd (1910) small llnttties of earshy
vrwti te VH-re found at seven11 ()f middotthe silver-leucl mineG at
Zeermn lthongh Pett(rrl (~gee not give S1)~~cifjc loenl tles
it t~) lLk~)lythnt middotth cervarlti te occurred ~t mJnes con tnlning
Do htrh proportion of ntimmy-hcftrtrL~ 8ulhidt1S 1n middott11e ore
( f a~kJc y)(-V r U~bmiddotmiddot middotf s) 0141 C~~ e-) v1t~L 1fmiddot~1e ~--i~l O~~middot~ ~1 Amiddotmiddot1 nn i1 ff~ U _ VI 1 -tL1oIi )-7 VJ
product of minert middot fmch Gtfj bOtllruVicri 1e nd hourl1oni t~e The
reliter] min0rJ1 stibiconi le hcu~ been re()rtnC at the 3prey
Mino (Pstterd 1910)shy
C11alcocite CuS- The only OOC1trtronce of ohalcoci tf~ notm1 in thtg fdjud~1
t~1 tl(1middot ~ t ~ ~- ~ ltJln A~f ~ _~ ~l f 1 flrr - middotr1- ~ 0 tt r r 2l~l bull etV1d 1 lJ le OScCLbull1 bullbullltfl m (Je bullbull~(d r) II clmiddot ) 1 -111i-bullbull lnlr_Y
111 middotmiddot 1) 1fr)k~ rlt (n middottmiddoti ~qlmiddotmv ~ll ~ltt O~1~middot-t-middot ne( bull3__ J~ ~-l )~~ f 1gt ~~ -~~ ofbull1 ft_l tt ) Hh-middot tl Ji~ ( 1r)~h~ bull L Cll ~bull ~ J_ gtcQ-shy
Ofi((Il1 chlttcocj te occur d i~) cove115 to tn mn laC~l~ e Gzuri 113
~~_1~ +ilT ~)(r~ ll middot~( A~middot_1w~ bull1 bullbull laquo7 j ~Y1I_~ J_~ t _~
C~f)~tlIl1-1middott~ (11(_~~__~ J ~
Covelltte if3 a rare 1Jj ner~l in he ~~oehGn l1tstr-lct
h11Vil1bEen obHerved I3Dtrnce funoun 1n only in ores )~rom sorne
of the mtnes 111 ~~he Ctlstoln pttrt of tv 8ren All of tfHJ
pecondr oj c-incQvel1- -- lt _ j lij bull ohH)V~d_ j~middot1 Dob t bull_b ly 01J -l ~~~- bull
r)rm111 aPlOuntD Of eovllitc iJce ~~8socdaijf wtth ahTdeomiddot
et to i rl maJachllo azurite eU1d (~3rthf iron oxIdes frorll ltho
qOl~~ ~nv (~ftl~rt~ _f~ YtJ 1 J fmiddot) ~ i ~lrmiddot n -~
J ) tt t I d J _ tgt r t1 bull1 S i1 ~bull ~ lIL-l e VfuI ~4amplmiddotbullbull_~
Tr1ces of fine cQvel15te hsve aloo been Doted in
)o
elmlcop~lrito from the ZeehanBeJl and Oonah m1 nes in rugenshy
ti-te from the 3praY [ini- and in tetrahodtt1(~ fromt(euro~
Zeehan-Weslerrl pound~-J ll e lit
Brnboll te I (PI Cl) ~_
tmiddotC) bull_ M( ill
S00 Ul1lt1nT (Hlrl-lrltITmiddotjt e tl (l) )2g)~ J - ~bullbullbullbulllIii - 1u 1 bull bull
11 (n~ )(nu ) 6~ nEvarHsite_1IMlI 3 1 4 111 6middot gtJ1211 Ill bullbullbull
1lSrejbull 111~A_ (18QJ1) ll1)lrtPJl_1 0 il_li~ cnr 1~LJp otlllkPl of (~ sno(raquo IenJ~ lr I oIl h bull J bull J ~ jltH
of botr~Jotd91 eVfmsite froJl1 the lount Zaehan f1ine 1111e
foll()v~tn ~rmlrsjs W8S pblltihed by ~hdth
p~o~ 1811~
AlryOl 4019 ~
P t) A 1 3(--1 i~ tt c jv2nlmiddotmiddotmiddott+~l 191C)middotl) 10) lCmiddoto ~fpo~ -0 ~vmiddotno+middot lttbullP ioI-JLl 1 tS- r ~1~ 0 ~ VJ L 0 V ( ~JJ vt ~O tI
zeehnll but ~tVe tlf) locoJi ty ltl(ita1 hl G ~her thDn st~middotttng
j-tat i t (gtC(~trrd ft bull t i7r_gtIn lcl1 4+-1 7middot-cltnmiddotlci nt~ _ ~_ - bull ~ H 0 u amp
nphRlcrite tl bull
Goetht te IITr-eo raquo z
rho lit~cmite1 OSCfl forrnftons f1SGoeintec1 witL never-al
lodes Ln the Zaehan aree are presumed middotto contrin uoetdte
ao the majr Iron oxide censtJ t~HHlt The idontU3 of the
iron melds has not bfHHl inveslin tEfY in ltletEl11
Several of tlCe iosfmns r(rt1)Xrlcd h1 et 1~v(1r1gt rIt3Ht~S
( middott c 2((0 09 C) f lt 1 1vmiddot f -r A ~ )11gt11J J~l ~tr-middot bull_~ ~~_ ~~ t ~uu VJt t~i t~8 silver fresent
tr 4~ ot l) t nm o] 1- ~middotd n lj 17gt ~ I n ~J n J L i)X L bull- 61 1 ClJ r lt1 middotdd J )e M kmiddot lJ s - v Lbull
tror0 rrlrely coppm c1rbomltes middotnd on-erg(me e02~per 3tl1jhides
~re aSrJocinted wih th(~ 5ron o~tde
flh~ b llClr botryoi d~~lvarie~y of limonite known RA
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
e I bull
Atacamite Cu (OH) Cl _ _u I bull t 2 3
middotPet~-t (otc~1Cj) TYntll hltltmiddot ltmiddotl itmiddot (~ ~ in~ ~clmiddotl f - - 0 X~~ Cmiddot~ ~_ f cttfVlloll~lJ - -~ ~ vtmiddotfL gJ
smal1smounts in ffFlixed oxtdtzec1 ore in middot~l Z~middotehan queen
lI0IJringo
Azurite eu] (Of0 2 COJ )2lIIl- It t
Copper (HJrbonates lSltlamp not (HimrrtOn in the ~ieehnn area
and have teen reported in the workingn of only tlffO mlntH13
~ lt-1 ] ~middotte m Q middotd poundfelllY t 111 bullbull11) cOmiddot tA till) Qh 1 ltV ziit OL_ V~~ i1 gt~-~j(A~ tltJr~ ri4O lW -J ~Vfoj~ J_ i ~JVAlJL ~ A~
110 rlringe bull rshy
Jal1er (1903) described ft lode f~wuth-weHt of the main
emiddotil J- middott-()knimiddot~ ~OtCtmiddottmiddot J) f middot~lmiddotmiddot middottmiddot emiddottmiddot~middot)It q~) V ~~ VI ~~lt l W bullbullbull 1~~bull ~~9 Il~JQ gt _Kl o~ ~lt~V 1 t C~ 1 2 J~Q
and ofman ch lltrLIned 111 cOtiJJ-er clrlI OIlfde but lt1d
nrrt Bl~~CLfy lJllhether the c~rbmnte waD aZlLrtte oX maJachi te
or 1Joth
h) 176-r )7)middot + f) n-tr1middotl-A ~1--~middotl-1middot1i~middotlAn (Vrl ~ - -~ ol-~C _ of J~_1t ~o(gtn~1lA-Q i~L- f ~-thI~i
frOD 1Ia-heymiddots Trilndiecwl1tcdns 9Ztui to in f1pound~sociation with
maJachi to eovellito and chaleocite
PetterrJ (1910) included Zerclhan in a list of the occur-
TeuroHlCltlHl of azurite in ~r~lI3tNln5at but dHI not fJttlhc art
ipeotf~JC loelttZI at ZeeJ1an
1)bmiddot ~bmiddotmiddot 0 ( ~ J)U )B5ndhetJltiite 2 J _ IlI-ltlI~ 2 6 1
l (1 0 10) t d~
11o -l 1 f hI ltIf It~PV-VlIIl rtilj 0 to )rt I)~Ll~ F u ~ ~JOJ1J ~ 0) Il Jl1tl IfUo 4- ilT~tli
ltonUftryftor ttplcos ore in the Intolog fi(ltji~ of w~ster-n
TiStsmanl~ltLPGt1jeTd recorded that b1n(lheimi to occurred in the
bull 111 If middot0 middot~middothmiddotmiddot ~ 1 ( ~h ) U n ~ la)lmiddotJzel ZvlH9 ~ 02_Jer O(hLtlre iI~
11l~ 11l1 Ifmiddotjl~o1) - 0Jt~~ltr~J3 nAnlr oe u CJllI 1middot)~ 1 C-lgtrmiddot1Q ~fi ~~-t -emiddotmiddot t ~~l~~) -J Ltrbull_6)lt~l - A Min
(ManglM1ose Hill) tlli3 was prnbabll l~rgelymiddot blnclhettitab-ut
may also have contgjiJodmassicot a )rellow lerld QXi0G
whteh occurred In EOm~) of middottth~ ~~oehan mines
( 1 - V v_ ~ gt frt~k 1ltbull Apound1Jl
lfIol I _110shy
0 (CerargyI1te wgSEtn iJIiportCtll1t c01lstlttlerrt 1ev~ral
poundITGJltifr)toua toaaan fonnationfJ in the Zeehan field bull Reshy
pOttZ4 indicatmiddote1hal tH1fH9 occurred majnl~r in the centrmiddotnl
ancl eef5ternnrta of tho field -Etnd the localLties include
middotmiddot~1 Jlt Q 1 - 110 h J bull tmiddotmiddotmiddot middotClmiddotmiddotmiddot1 t t tJvesv~ll I)I~lY jmiddot()reuroh1Cetmiddotnf4-(~~ Hie middotItnbull )0 Su IlP s anu
ZecllUl jlleon minea am ibe nChloride- Loje tf in th(~ Colonel
North ctrea
The halHle wnso(~cant(nlally reporfod to 1)0 t e hr-onian
v ~Y omiddotr c rll 4middot ~ middotx ~~ol-41r 1 1 I tlt J ~- 84 ry I E It~ nn as elmiddot e 1 cbullbullbull_ ic variety was
01 middottmiddot1 ~ I~l ~ ~rIeuroJcoJded Co v ~i t -tr~~ ~l rJ J t ~ t~ t JUtH~tt01l 1]~1d l~efgthan2Oeen mtnes
and near Balwtrtlpa Mine
Namiddottive ~lilver vrasoften 9sr1oci~)teurod wjih the ba-Jives in
middothbcoc ossnn fOrmt1tioufl and ~]jlvetmiddot aatJDlS up to 2000 ozs
per ton ViJere recotlmiddotd
( -ltt1middot$0 P1--C0 0 3 a -_~
CeroB21ite WHoS leporta(t to be a cormtlturmt of the ltrx
idizad zone of Joverul orc-Dor1irfl in tho ochan areflshy
r ~t middotlgt crmiddot1(lt~ (ccgtgt lj lgtv ~lmiddottmiddotP 1t-J-g middot1middot11lt~(I shytlet+Al ~-H~1 (J (1(10 1) AOmiddotmiddot)J oh GO- t lt middott11tojmiddot ~ trtlto ~I $ fllll~J t ~AtOfJ li$
fllirly large quantities E~t the Silver Zeehall)rueen
S~71VBst~~r Austr~l nnd other mine at Zeehall It T111es
Jmiddot t r~rmiddottlgtrl o~tuttmiddot 1 1middot1middotmiddot c~ lcn]emiddot+_lmiddottC(1n91) c-~d i~ E~~~I (19)dJ 11J~]J ~Imiddott 1011 tlgt~iVkj~ 1ljJ ~t Dmiddot47 bull 1lt1 uL IJ~ ~
~il le ([ g~~ 1ltgt0 p 1middot1)~-J~ I i~~A-tll ~l-f1l G l1J - bull
S130e1men no 22169 frOl1 the IaBmania11 tiJuseum 001100shy
tion labelled 1~endh111tte ~1ilver (Zeehan) Qneen JUne
229
Z(~ehnntl has been identiied fUl (Hrussll~e l)y meaYlE of X-ray
dliffrnoM on
( rmiddotmiddot 11middot-l e SOfO ()~~-~_~~ ( 4
oco)r111 t1 to Pertterd (1910) small llnttties of earshy
vrwti te VH-re found at seven11 ()f middotthe silver-leucl mineG at
Zeermn lthongh Pett(rrl (~gee not give S1)~~cifjc loenl tles
it t~) lLk~)lythnt middotth cervarlti te occurred ~t mJnes con tnlning
Do htrh proportion of ntimmy-hcftrtrL~ 8ulhidt1S 1n middott11e ore
( f a~kJc y)(-V r U~bmiddotmiddot middotf s) 0141 C~~ e-) v1t~L 1fmiddot~1e ~--i~l O~~middot~ ~1 Amiddotmiddot1 nn i1 ff~ U _ VI 1 -tL1oIi )-7 VJ
product of minert middot fmch Gtfj bOtllruVicri 1e nd hourl1oni t~e The
reliter] min0rJ1 stibiconi le hcu~ been re()rtnC at the 3prey
Mino (Pstterd 1910)shy
C11alcocite CuS- The only OOC1trtronce of ohalcoci tf~ notm1 in thtg fdjud~1
t~1 tl(1middot ~ t ~ ~- ~ ltJln A~f ~ _~ ~l f 1 flrr - middotr1- ~ 0 tt r r 2l~l bull etV1d 1 lJ le OScCLbull1 bullbullltfl m (Je bullbull~(d r) II clmiddot ) 1 -111i-bullbull lnlr_Y
111 middotmiddot 1) 1fr)k~ rlt (n middottmiddoti ~qlmiddotmv ~ll ~ltt O~1~middot-t-middot ne( bull3__ J~ ~-l )~~ f 1gt ~~ -~~ ofbull1 ft_l tt ) Hh-middot tl Ji~ ( 1r)~h~ bull L Cll ~bull ~ J_ gtcQ-shy
Ofi((Il1 chlttcocj te occur d i~) cove115 to tn mn laC~l~ e Gzuri 113
~~_1~ +ilT ~)(r~ ll middot~( A~middot_1w~ bull1 bullbull laquo7 j ~Y1I_~ J_~ t _~
C~f)~tlIl1-1middott~ (11(_~~__~ J ~
Covelltte if3 a rare 1Jj ner~l in he ~~oehGn l1tstr-lct
h11Vil1bEen obHerved I3Dtrnce funoun 1n only in ores )~rom sorne
of the mtnes 111 ~~he Ctlstoln pttrt of tv 8ren All of tfHJ
pecondr oj c-incQvel1- -- lt _ j lij bull ohH)V~d_ j~middot1 Dob t bull_b ly 01J -l ~~~- bull
r)rm111 aPlOuntD Of eovllitc iJce ~~8socdaijf wtth ahTdeomiddot
et to i rl maJachllo azurite eU1d (~3rthf iron oxIdes frorll ltho
qOl~~ ~nv (~ftl~rt~ _f~ YtJ 1 J fmiddot) ~ i ~lrmiddot n -~
J ) tt t I d J _ tgt r t1 bull1 S i1 ~bull ~ lIL-l e VfuI ~4amplmiddotbullbull_~
Tr1ces of fine cQvel15te hsve aloo been Doted in
)o
elmlcop~lrito from the ZeehanBeJl and Oonah m1 nes in rugenshy
ti-te from the 3praY [ini- and in tetrahodtt1(~ fromt(euro~
Zeehan-Weslerrl pound~-J ll e lit
Brnboll te I (PI Cl) ~_
tmiddotC) bull_ M( ill
S00 Ul1lt1nT (Hlrl-lrltITmiddotjt e tl (l) )2g)~ J - ~bullbullbullbulllIii - 1u 1 bull bull
11 (n~ )(nu ) 6~ nEvarHsite_1IMlI 3 1 4 111 6middot gtJ1211 Ill bullbullbull
1lSrejbull 111~A_ (18QJ1) ll1)lrtPJl_1 0 il_li~ cnr 1~LJp otlllkPl of (~ sno(raquo IenJ~ lr I oIl h bull J bull J ~ jltH
of botr~Jotd91 eVfmsite froJl1 the lount Zaehan f1ine 1111e
foll()v~tn ~rmlrsjs W8S pblltihed by ~hdth
p~o~ 1811~
AlryOl 4019 ~
P t) A 1 3(--1 i~ tt c jv2nlmiddotmiddotmiddott+~l 191C)middotl) 10) lCmiddoto ~fpo~ -0 ~vmiddotno+middot lttbullP ioI-JLl 1 tS- r ~1~ 0 ~ VJ L 0 V ( ~JJ vt ~O tI
zeehnll but ~tVe tlf) locoJi ty ltl(ita1 hl G ~her thDn st~middotttng
j-tat i t (gtC(~trrd ft bull t i7r_gtIn lcl1 4+-1 7middot-cltnmiddotlci nt~ _ ~_ - bull ~ H 0 u amp
nphRlcrite tl bull
Goetht te IITr-eo raquo z
rho lit~cmite1 OSCfl forrnftons f1SGoeintec1 witL never-al
lodes Ln the Zaehan aree are presumed middotto contrin uoetdte
ao the majr Iron oxide censtJ t~HHlt The idontU3 of the
iron melds has not bfHHl inveslin tEfY in ltletEl11
Several of tlCe iosfmns r(rt1)Xrlcd h1 et 1~v(1r1gt rIt3Ht~S
( middott c 2((0 09 C) f lt 1 1vmiddot f -r A ~ )11gt11J J~l ~tr-middot bull_~ ~~_ ~~ t ~uu VJt t~i t~8 silver fresent
tr 4~ ot l) t nm o] 1- ~middotd n lj 17gt ~ I n ~J n J L i)X L bull- 61 1 ClJ r lt1 middotdd J )e M kmiddot lJ s - v Lbull
tror0 rrlrely coppm c1rbomltes middotnd on-erg(me e02~per 3tl1jhides
~re aSrJocinted wih th(~ 5ron o~tde
flh~ b llClr botryoi d~~lvarie~y of limonite known RA
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
may also have contgjiJodmassicot a )rellow lerld QXi0G
whteh occurred In EOm~) of middottth~ ~~oehan mines
( 1 - V v_ ~ gt frt~k 1ltbull Apound1Jl
lfIol I _110shy
0 (CerargyI1te wgSEtn iJIiportCtll1t c01lstlttlerrt 1ev~ral
poundITGJltifr)toua toaaan fonnationfJ in the Zeehan field bull Reshy
pOttZ4 indicatmiddote1hal tH1fH9 occurred majnl~r in the centrmiddotnl
ancl eef5ternnrta of tho field -Etnd the localLties include
middotmiddot~1 Jlt Q 1 - 110 h J bull tmiddotmiddotmiddot middotClmiddotmiddotmiddot1 t t tJvesv~ll I)I~lY jmiddot()reuroh1Cetmiddotnf4-(~~ Hie middotItnbull )0 Su IlP s anu
ZecllUl jlleon minea am ibe nChloride- Loje tf in th(~ Colonel
North ctrea
The halHle wnso(~cant(nlally reporfod to 1)0 t e hr-onian
v ~Y omiddotr c rll 4middot ~ middotx ~~ol-41r 1 1 I tlt J ~- 84 ry I E It~ nn as elmiddot e 1 cbullbullbull_ ic variety was
01 middottmiddot1 ~ I~l ~ ~rIeuroJcoJded Co v ~i t -tr~~ ~l rJ J t ~ t~ t JUtH~tt01l 1]~1d l~efgthan2Oeen mtnes
and near Balwtrtlpa Mine
Namiddottive ~lilver vrasoften 9sr1oci~)teurod wjih the ba-Jives in
middothbcoc ossnn fOrmt1tioufl and ~]jlvetmiddot aatJDlS up to 2000 ozs
per ton ViJere recotlmiddotd
( -ltt1middot$0 P1--C0 0 3 a -_~
CeroB21ite WHoS leporta(t to be a cormtlturmt of the ltrx
idizad zone of Joverul orc-Dor1irfl in tho ochan areflshy
r ~t middotlgt crmiddot1(lt~ (ccgtgt lj lgtv ~lmiddottmiddotP 1t-J-g middot1middot11lt~(I shytlet+Al ~-H~1 (J (1(10 1) AOmiddotmiddot)J oh GO- t lt middott11tojmiddot ~ trtlto ~I $ fllll~J t ~AtOfJ li$
fllirly large quantities E~t the Silver Zeehall)rueen
S~71VBst~~r Austr~l nnd other mine at Zeehall It T111es
Jmiddot t r~rmiddottlgtrl o~tuttmiddot 1 1middot1middotmiddot c~ lcn]emiddot+_lmiddottC(1n91) c-~d i~ E~~~I (19)dJ 11J~]J ~Imiddott 1011 tlgt~iVkj~ 1ljJ ~t Dmiddot47 bull 1lt1 uL IJ~ ~
~il le ([ g~~ 1ltgt0 p 1middot1)~-J~ I i~~A-tll ~l-f1l G l1J - bull
S130e1men no 22169 frOl1 the IaBmania11 tiJuseum 001100shy
tion labelled 1~endh111tte ~1ilver (Zeehan) Qneen JUne
229
Z(~ehnntl has been identiied fUl (Hrussll~e l)y meaYlE of X-ray
dliffrnoM on
( rmiddotmiddot 11middot-l e SOfO ()~~-~_~~ ( 4
oco)r111 t1 to Pertterd (1910) small llnttties of earshy
vrwti te VH-re found at seven11 ()f middotthe silver-leucl mineG at
Zeermn lthongh Pett(rrl (~gee not give S1)~~cifjc loenl tles
it t~) lLk~)lythnt middotth cervarlti te occurred ~t mJnes con tnlning
Do htrh proportion of ntimmy-hcftrtrL~ 8ulhidt1S 1n middott11e ore
( f a~kJc y)(-V r U~bmiddotmiddot middotf s) 0141 C~~ e-) v1t~L 1fmiddot~1e ~--i~l O~~middot~ ~1 Amiddotmiddot1 nn i1 ff~ U _ VI 1 -tL1oIi )-7 VJ
product of minert middot fmch Gtfj bOtllruVicri 1e nd hourl1oni t~e The
reliter] min0rJ1 stibiconi le hcu~ been re()rtnC at the 3prey
Mino (Pstterd 1910)shy
C11alcocite CuS- The only OOC1trtronce of ohalcoci tf~ notm1 in thtg fdjud~1
t~1 tl(1middot ~ t ~ ~- ~ ltJln A~f ~ _~ ~l f 1 flrr - middotr1- ~ 0 tt r r 2l~l bull etV1d 1 lJ le OScCLbull1 bullbullltfl m (Je bullbull~(d r) II clmiddot ) 1 -111i-bullbull lnlr_Y
111 middotmiddot 1) 1fr)k~ rlt (n middottmiddoti ~qlmiddotmv ~ll ~ltt O~1~middot-t-middot ne( bull3__ J~ ~-l )~~ f 1gt ~~ -~~ ofbull1 ft_l tt ) Hh-middot tl Ji~ ( 1r)~h~ bull L Cll ~bull ~ J_ gtcQ-shy
Ofi((Il1 chlttcocj te occur d i~) cove115 to tn mn laC~l~ e Gzuri 113
~~_1~ +ilT ~)(r~ ll middot~( A~middot_1w~ bull1 bullbull laquo7 j ~Y1I_~ J_~ t _~
C~f)~tlIl1-1middott~ (11(_~~__~ J ~
Covelltte if3 a rare 1Jj ner~l in he ~~oehGn l1tstr-lct
h11Vil1bEen obHerved I3Dtrnce funoun 1n only in ores )~rom sorne
of the mtnes 111 ~~he Ctlstoln pttrt of tv 8ren All of tfHJ
pecondr oj c-incQvel1- -- lt _ j lij bull ohH)V~d_ j~middot1 Dob t bull_b ly 01J -l ~~~- bull
r)rm111 aPlOuntD Of eovllitc iJce ~~8socdaijf wtth ahTdeomiddot
et to i rl maJachllo azurite eU1d (~3rthf iron oxIdes frorll ltho
qOl~~ ~nv (~ftl~rt~ _f~ YtJ 1 J fmiddot) ~ i ~lrmiddot n -~
J ) tt t I d J _ tgt r t1 bull1 S i1 ~bull ~ lIL-l e VfuI ~4amplmiddotbullbull_~
Tr1ces of fine cQvel15te hsve aloo been Doted in
)o
elmlcop~lrito from the ZeehanBeJl and Oonah m1 nes in rugenshy
ti-te from the 3praY [ini- and in tetrahodtt1(~ fromt(euro~
Zeehan-Weslerrl pound~-J ll e lit
Brnboll te I (PI Cl) ~_
tmiddotC) bull_ M( ill
S00 Ul1lt1nT (Hlrl-lrltITmiddotjt e tl (l) )2g)~ J - ~bullbullbullbulllIii - 1u 1 bull bull
11 (n~ )(nu ) 6~ nEvarHsite_1IMlI 3 1 4 111 6middot gtJ1211 Ill bullbullbull
1lSrejbull 111~A_ (18QJ1) ll1)lrtPJl_1 0 il_li~ cnr 1~LJp otlllkPl of (~ sno(raquo IenJ~ lr I oIl h bull J bull J ~ jltH
of botr~Jotd91 eVfmsite froJl1 the lount Zaehan f1ine 1111e
foll()v~tn ~rmlrsjs W8S pblltihed by ~hdth
p~o~ 1811~
AlryOl 4019 ~
P t) A 1 3(--1 i~ tt c jv2nlmiddotmiddotmiddott+~l 191C)middotl) 10) lCmiddoto ~fpo~ -0 ~vmiddotno+middot lttbullP ioI-JLl 1 tS- r ~1~ 0 ~ VJ L 0 V ( ~JJ vt ~O tI
zeehnll but ~tVe tlf) locoJi ty ltl(ita1 hl G ~her thDn st~middotttng
j-tat i t (gtC(~trrd ft bull t i7r_gtIn lcl1 4+-1 7middot-cltnmiddotlci nt~ _ ~_ - bull ~ H 0 u amp
nphRlcrite tl bull
Goetht te IITr-eo raquo z
rho lit~cmite1 OSCfl forrnftons f1SGoeintec1 witL never-al
lodes Ln the Zaehan aree are presumed middotto contrin uoetdte
ao the majr Iron oxide censtJ t~HHlt The idontU3 of the
iron melds has not bfHHl inveslin tEfY in ltletEl11
Several of tlCe iosfmns r(rt1)Xrlcd h1 et 1~v(1r1gt rIt3Ht~S
( middott c 2((0 09 C) f lt 1 1vmiddot f -r A ~ )11gt11J J~l ~tr-middot bull_~ ~~_ ~~ t ~uu VJt t~i t~8 silver fresent
tr 4~ ot l) t nm o] 1- ~middotd n lj 17gt ~ I n ~J n J L i)X L bull- 61 1 ClJ r lt1 middotdd J )e M kmiddot lJ s - v Lbull
tror0 rrlrely coppm c1rbomltes middotnd on-erg(me e02~per 3tl1jhides
~re aSrJocinted wih th(~ 5ron o~tde
flh~ b llClr botryoi d~~lvarie~y of limonite known RA
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
229
Z(~ehnntl has been identiied fUl (Hrussll~e l)y meaYlE of X-ray
dliffrnoM on
( rmiddotmiddot 11middot-l e SOfO ()~~-~_~~ ( 4
oco)r111 t1 to Pertterd (1910) small llnttties of earshy
vrwti te VH-re found at seven11 ()f middotthe silver-leucl mineG at
Zeermn lthongh Pett(rrl (~gee not give S1)~~cifjc loenl tles
it t~) lLk~)lythnt middotth cervarlti te occurred ~t mJnes con tnlning
Do htrh proportion of ntimmy-hcftrtrL~ 8ulhidt1S 1n middott11e ore
( f a~kJc y)(-V r U~bmiddotmiddot middotf s) 0141 C~~ e-) v1t~L 1fmiddot~1e ~--i~l O~~middot~ ~1 Amiddotmiddot1 nn i1 ff~ U _ VI 1 -tL1oIi )-7 VJ
product of minert middot fmch Gtfj bOtllruVicri 1e nd hourl1oni t~e The
reliter] min0rJ1 stibiconi le hcu~ been re()rtnC at the 3prey
Mino (Pstterd 1910)shy
C11alcocite CuS- The only OOC1trtronce of ohalcoci tf~ notm1 in thtg fdjud~1
t~1 tl(1middot ~ t ~ ~- ~ ltJln A~f ~ _~ ~l f 1 flrr - middotr1- ~ 0 tt r r 2l~l bull etV1d 1 lJ le OScCLbull1 bullbullltfl m (Je bullbull~(d r) II clmiddot ) 1 -111i-bullbull lnlr_Y
111 middotmiddot 1) 1fr)k~ rlt (n middottmiddoti ~qlmiddotmv ~ll ~ltt O~1~middot-t-middot ne( bull3__ J~ ~-l )~~ f 1gt ~~ -~~ ofbull1 ft_l tt ) Hh-middot tl Ji~ ( 1r)~h~ bull L Cll ~bull ~ J_ gtcQ-shy
Ofi((Il1 chlttcocj te occur d i~) cove115 to tn mn laC~l~ e Gzuri 113
~~_1~ +ilT ~)(r~ ll middot~( A~middot_1w~ bull1 bullbull laquo7 j ~Y1I_~ J_~ t _~
C~f)~tlIl1-1middott~ (11(_~~__~ J ~
Covelltte if3 a rare 1Jj ner~l in he ~~oehGn l1tstr-lct
h11Vil1bEen obHerved I3Dtrnce funoun 1n only in ores )~rom sorne
of the mtnes 111 ~~he Ctlstoln pttrt of tv 8ren All of tfHJ
pecondr oj c-incQvel1- -- lt _ j lij bull ohH)V~d_ j~middot1 Dob t bull_b ly 01J -l ~~~- bull
r)rm111 aPlOuntD Of eovllitc iJce ~~8socdaijf wtth ahTdeomiddot
et to i rl maJachllo azurite eU1d (~3rthf iron oxIdes frorll ltho
qOl~~ ~nv (~ftl~rt~ _f~ YtJ 1 J fmiddot) ~ i ~lrmiddot n -~
J ) tt t I d J _ tgt r t1 bull1 S i1 ~bull ~ lIL-l e VfuI ~4amplmiddotbullbull_~
Tr1ces of fine cQvel15te hsve aloo been Doted in
)o
elmlcop~lrito from the ZeehanBeJl and Oonah m1 nes in rugenshy
ti-te from the 3praY [ini- and in tetrahodtt1(~ fromt(euro~
Zeehan-Weslerrl pound~-J ll e lit
Brnboll te I (PI Cl) ~_
tmiddotC) bull_ M( ill
S00 Ul1lt1nT (Hlrl-lrltITmiddotjt e tl (l) )2g)~ J - ~bullbullbullbulllIii - 1u 1 bull bull
11 (n~ )(nu ) 6~ nEvarHsite_1IMlI 3 1 4 111 6middot gtJ1211 Ill bullbullbull
1lSrejbull 111~A_ (18QJ1) ll1)lrtPJl_1 0 il_li~ cnr 1~LJp otlllkPl of (~ sno(raquo IenJ~ lr I oIl h bull J bull J ~ jltH
of botr~Jotd91 eVfmsite froJl1 the lount Zaehan f1ine 1111e
foll()v~tn ~rmlrsjs W8S pblltihed by ~hdth
p~o~ 1811~
AlryOl 4019 ~
P t) A 1 3(--1 i~ tt c jv2nlmiddotmiddotmiddott+~l 191C)middotl) 10) lCmiddoto ~fpo~ -0 ~vmiddotno+middot lttbullP ioI-JLl 1 tS- r ~1~ 0 ~ VJ L 0 V ( ~JJ vt ~O tI
zeehnll but ~tVe tlf) locoJi ty ltl(ita1 hl G ~her thDn st~middotttng
j-tat i t (gtC(~trrd ft bull t i7r_gtIn lcl1 4+-1 7middot-cltnmiddotlci nt~ _ ~_ - bull ~ H 0 u amp
nphRlcrite tl bull
Goetht te IITr-eo raquo z
rho lit~cmite1 OSCfl forrnftons f1SGoeintec1 witL never-al
lodes Ln the Zaehan aree are presumed middotto contrin uoetdte
ao the majr Iron oxide censtJ t~HHlt The idontU3 of the
iron melds has not bfHHl inveslin tEfY in ltletEl11
Several of tlCe iosfmns r(rt1)Xrlcd h1 et 1~v(1r1gt rIt3Ht~S
( middott c 2((0 09 C) f lt 1 1vmiddot f -r A ~ )11gt11J J~l ~tr-middot bull_~ ~~_ ~~ t ~uu VJt t~i t~8 silver fresent
tr 4~ ot l) t nm o] 1- ~middotd n lj 17gt ~ I n ~J n J L i)X L bull- 61 1 ClJ r lt1 middotdd J )e M kmiddot lJ s - v Lbull
tror0 rrlrely coppm c1rbomltes middotnd on-erg(me e02~per 3tl1jhides
~re aSrJocinted wih th(~ 5ron o~tde
flh~ b llClr botryoi d~~lvarie~y of limonite known RA
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
)o
elmlcop~lrito from the ZeehanBeJl and Oonah m1 nes in rugenshy
ti-te from the 3praY [ini- and in tetrahodtt1(~ fromt(euro~
Zeehan-Weslerrl pound~-J ll e lit
Brnboll te I (PI Cl) ~_
tmiddotC) bull_ M( ill
S00 Ul1lt1nT (Hlrl-lrltITmiddotjt e tl (l) )2g)~ J - ~bullbullbullbulllIii - 1u 1 bull bull
11 (n~ )(nu ) 6~ nEvarHsite_1IMlI 3 1 4 111 6middot gtJ1211 Ill bullbullbull
1lSrejbull 111~A_ (18QJ1) ll1)lrtPJl_1 0 il_li~ cnr 1~LJp otlllkPl of (~ sno(raquo IenJ~ lr I oIl h bull J bull J ~ jltH
of botr~Jotd91 eVfmsite froJl1 the lount Zaehan f1ine 1111e
foll()v~tn ~rmlrsjs W8S pblltihed by ~hdth
p~o~ 1811~
AlryOl 4019 ~
P t) A 1 3(--1 i~ tt c jv2nlmiddotmiddotmiddott+~l 191C)middotl) 10) lCmiddoto ~fpo~ -0 ~vmiddotno+middot lttbullP ioI-JLl 1 tS- r ~1~ 0 ~ VJ L 0 V ( ~JJ vt ~O tI
zeehnll but ~tVe tlf) locoJi ty ltl(ita1 hl G ~her thDn st~middotttng
j-tat i t (gtC(~trrd ft bull t i7r_gtIn lcl1 4+-1 7middot-cltnmiddotlci nt~ _ ~_ - bull ~ H 0 u amp
nphRlcrite tl bull
Goetht te IITr-eo raquo z
rho lit~cmite1 OSCfl forrnftons f1SGoeintec1 witL never-al
lodes Ln the Zaehan aree are presumed middotto contrin uoetdte
ao the majr Iron oxide censtJ t~HHlt The idontU3 of the
iron melds has not bfHHl inveslin tEfY in ltletEl11
Several of tlCe iosfmns r(rt1)Xrlcd h1 et 1~v(1r1gt rIt3Ht~S
( middott c 2((0 09 C) f lt 1 1vmiddot f -r A ~ )11gt11J J~l ~tr-middot bull_~ ~~_ ~~ t ~uu VJt t~i t~8 silver fresent
tr 4~ ot l) t nm o] 1- ~middotd n lj 17gt ~ I n ~J n J L i)X L bull- 61 1 ClJ r lt1 middotdd J )e M kmiddot lJ s - v Lbull
tror0 rrlrely coppm c1rbomltes middotnd on-erg(me e02~per 3tl1jhides
~re aSrJocinted wih th(~ 5ron o~tde
flh~ b llClr botryoi d~~lvarie~y of limonite known RA
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
-----
231bull
middotrmiddotmiddot~ l middotmiddot ~middoti i- bull 1 l~ t ) b r t i-rl 11 (1Q10) t 0 1H JL e~J ) JH rJ 1middoteImiddott8 TBiCl1 (l etlt yl e 1 (1 bull it) UY1 ng
gtf 1 C tTltl 1 I J Tomiddot l 1~~ti ( J 11 f1t Hl Iflid)~ I I r) shyU 1I elcl 018dlt11) ne 1 bulln~11 shy
i)ref3fntrmiddotd in the Tasmcmion Niusaum collect on by a IFrge
10 lI 1 iro (y~J~_j -(J) f i-lTl0C l t~1 11 ccbullnn rom iC r 1 ~
Goa1HXi to ZnSO A 7HO ~~~~-- tt c
Petterd (1910) reccrdeJ th(~ occurrence of gba]Yr~i to
t he Comstock i1ir10 7 but grAve no dotail of abundance
~ (~ (lE) gtU C Hi ~-ll nccri te Je2gtJ~21middotJ5G 4 HH2 -----~-~
w~ Jl (1)n~ 13 middotmiddotmiddot t -4l(~ -Cl CP p h~ ~-bullbullbull tllclmiddotbull er 5p I J8J e) Jltv )middotUo0J u ~ bulldllU J 0
(middott Clt ~OlllOT --~ - -- lt lO(~)-CIlt 1 ~~I ltmiddotc~~middot l - )L lo)C~ ~ (l bull-J J _t~middot~tn c~ lJ tlJti~ It hmiddotl J J tl0 [_lll~ 1l j JdCCl 1 4J11
nmiddot (~1)1 ()e~Urrirlg 5 n tlnr)Ori~tOUS mH1es a~JjQclHte1 iPt t ~l J_~r~t t j c~
OJmiddot~ exposed in the lower tunnel
(r m (1 111 A 7 ) f ~ () 1t 4- lgt f 1 JC SJElcrJen f )Ot 0 -1J~ 1(1( bullbull J euroI rOle t 11i 0 ]J 0 all ty
1~1 rrJpr9flGIlto(l in iho ~rnfHnanif-Jtn iluseutcl col1el1tion
nqmiddot (middott1) tc) 1 0Hrd r()matfne~d te cg4 ) 3 tmiddot2 middot
TIH3 only reccJll of hy(1roI1fjrH~dlt() tn tho ~~ehan (jmiddot1lt1
5fl that by Pettn~ (1910 p97) who reprte(~ solid allnoat
(ri~e rtJdtntinmiddot bunchee ll of hJN]tgtO)f--wnesiiJe It tlumiddot) COITfstoek
Mine
_ _--_~-_ _shy
b middot0Kerillelii 0 ~ gt )-_Qlaquo__
c
J~middotmiddot+ltl l (1911~1
1middotmiddot) 102) (ld 0 f t i)middotlmiddott tZ 1middot_~1(11 L~Vt Ilmiddot-l L~middot~I~-bullbullJ k middotjrmiddotmiddotmiddotlmiddotp bull ) LltVbull llt J~ ~Lte~)_
f017ilfl tin ex~~rQrlely lirlitJ0d luCJl ~i t~l impl~rlted in the
frctnros of j m(~Honi-(J et tcRr-itntl ZE~ah~in ~~Ilinen As
oescrlbBd earlier (pIQ4-) the r(lii1er~l rcferrerl to ao jalfieshy
8onjte tB in fnct 110ul1Iuere Tho rmme 3rits~l Z(leurohan
Mine was sometjmen lm~~l~ for the Sr1yMiliHih
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
232
bull O11 ) ( Ir )M~lEHhi te CU2 1 2 )3
The occurrence of (~Orfper carbonates at Ze~han has been
de 7ribmiddotmiddotl umiddotmiddot~rgt ttI7middotlmiddotmiddotmiddotj IltgtHf y )7)
bullbull p 1l~_
3middot J- ~ ) st~lIJ t1Ii1gt11LJ )0 1 bull L bull
0~~~B_(~rG 1~j10) -J~la+ 1 v -U f~I~ _ J U ()f mi181P-ln in 1 ~)i~iln__klt et 118 rlOt
1 ~ ~ tl r7) ~ -- -~~rmiddot7Imiddotmiddotmiddotmiddot~t le )~~ f -~ r1) lt t ~ 1_ )_1 Ll_~ cr~ v- H) C (~b )1 Llrmiddotmiddotl e
NU1S 3i C 0 1 11 ~~
ir~ocmiddotlmiddotCO-tlj(jj)i-_~ ~~L wlt -J hvlt~ middot~~tmiddottmiddotmiddotmiddot- -
(IJ10 ~~ 11])rechd~middot-~ ~~gt bull
13(61gt -~J
occuriing lin bnitod quantttl at ~H~V(~ldl or lhe Zeehm
sJ1ver-lead lnineB fl t but no ])smiddotticuJJrmiddot Gl~LnEm H(~ lfJ(m ~~Lolled
Blndhe1mi ~E~ and flcmarJ ore 11 hnvG hr en re corlle tViC
- 1 lgtampeohanlueen ~md d li trupt H mirH33 ( 1~v v (~J ~- l310 I~11eY
1- 1 PldJ~ H 10-lt1 OX-~ d P 11 WFj nlt ild rLiit)01_ r IJ 1 ler(terl bull _ 14 O t- I ~ 1
( () ) -I middotmiddotmiddotJrlf 1 P c ( ) t)Xl i sect~lLJ~) ic ( t Lubull)) ~ ~J J) It 1~ probable (~Qtl1~tjlt
uted l t leasi iJrt of the materiela referred to In ~heme
rqwcts
IWiatlochi te ih1Clbull_- 11
Tle only Ie~))Jmiddott 01 Jrutloc~d~e ~middott Zee~1u1 imiddot ~h6lt by
ret~er-d (1910)
~Imiddotmiddoto-imiddotmiddotmiddott t gt~ () 113) (10- middotrmiddotmiddot ~ inJ C 1 a 0 6 -CId 1 )e (~llll In~Jl ~Glthl
tfbul crYi31tJl3 of L~ gleenl~l-gl(Y colcmr rtp celltly rare
lt1~ E~O r~ i [et t(~d ll ~~ r~1 iXE)-1 fftll hi d B ~Jt(J r~ gt~1~1) ~i rl~ 11 c~ 01() Ei 0 r IGf~l(l
at tl~ fJ(LveEJtr Tiine tl and Htn rillnll pampLcl-le~1 )f a huwyshy
~ 11 ] c ~ J tmiddot bull c1 n bull -+ 1 r ~ t middot 1middot 711 It1S eJ _()U- co Jtli rl~J ~ ~c )e lJ) tj tf(-il~ t4 tJ tJ0 ~c~()i Iamp~j~~ ~i~ J1~ sICO (411
~~ -
Tielantertte 1 euro lt() 4- ilt2 -bullbull M Ill INbullbullbullbull
I (1(91middot 1 tb bull1emiddotI~er(l 0) reeolc edli(l nccvrence OJI( lErX(EC C
etow li-~ f~-~Jl (~~t(middott~middot~middot~y- ~~ -I) (~ Omiddotmiddotmiddotmiddotrmiddot~-J~middot ~~t cmiddot~)-middotmiddotJ-~-( middot1 )middotq L11~ lmiddotmiddott ~ J lJ_ u Jer ldJwmiddotbullll ttlt v 1 II ltI Ut uU ~middotUbOtl J h
hEld formod gtiB l~he rCEHl1 of dOCOlItpodtion of lwrt middottein the tl __~ tl(] UflfJ-( 1Jor1~l Jltl~O
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
----------------
233
tUmetite PbS(AJO4 PO4)3C1 Mt
Mimetite occurred in oxicljzefl ore from tho Suaannite
~~ C 4 P-) 11j ~ nmiddotI tt ) it f-C n ( 11 InhrLlalX l - ne lt bullbull1(1 1i9 vI anrna ILt __e
The mimettte found at t 1ie SlJsanni te Mine wno originally
tllouglrt to be the leadhilli te vUJ~ety knmjfl as 8u8anni te
hence the nrUH~l of the mine Lmter it wee sllOwn by
ft 1 Petterd fll1d N A I1eLeod (in rrwelvetreee 1901a) to be
CflJlpyli te a variety of miJlleti te C9jThJJ~rlite Wf~S alao found
at the Britanllta NifHh
Some of the mtmetite from the Britannir~ Tline was desshy
orfbad by ~lvmlvetrees (1901h) as a new mineral which he
cal1eff flpotterdite However p~nali~raon (1908) fOlwd it to
be a v~rieurolty of mimEJti te Al1d(~rsm questtoned -the chemical
analysls pttbltshed by rrwelvetree9 and Pllbl-1 ~)h0d lWQ fuXther
~malJses the mean of w~11ch to s110vm belc~w
PhO 77 14~ --shy~ - 0
1) laquo 1795Co
250t1gt2deg5
Cl 2461middot
JltU19 ~y)uljm1middott Pb3A13P04)2(OH)5middotU20
Petterd (1901 p139) recorded plWJ1bogurnrni te as havtng
been found eCtached to partially decompofH~d galma tt at the
Brttteh Zeehan (Spray) Mine
jh~~ onljr spectmen of plvibogVJuni tE~ fron1 Zeehttn in the
TaHmarniaJl MtUHlurn col1ectdon is epocimen noX20e3 from the
Zaehom-Viontema Mine The specimenootlsists of galena VIhi-ch
h~H3 been perLially fl1 tared tOPSIOfopmiddoth1 ta which 1193 tin
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
234
I)) rmiddott i n 1 J v 1 -I C e~ Lt bullbull ~~1 PWi11) romr 11 tt 1 180middot~tlrnl l~ eer1 jffbull ~~C~~ ~_middoth ~- (l J _A~ ~ bull bull lt ~ - (r fJogtbullbullbullbull ~_
q~t ltfor 3 ) 1_ l 1 ll) bull
()Pvro l1JBle n 2 ~~-_-_~ -_
Th(~ only reportod OC(~UrrOnC0 or pvroltHJ~to in 1e
ZeBhrUl field if) BL NmlmiddotmiddotlnEIGe IB11 7 WH~l(~ Lt is RAo(d~ttetl
Vi1tj1 lt1n~)njte itl llf) n1]tjfsmiddot~tnireTmiddotOlA~middot~ ~~OfJE1trl Cmiddot~-middot~J nG~~ middott~le
l~i 1 (1(6 3) J_CIhc- 1- -rrtmiddoti~l ~) +~ -1l0middoth_middot I~J ~ ~H~ bull~ l 1Ciitll ~ t C4 rJ ~JAg~fU-(J vfL1 1 gt1)~ gtmiddot~~jvmiddotI13 ~l()-Jl
fro~ the oxidntio~ I)rj CC ~~)nJ rnD ll~etJi ~rCeOtlCj ~J i d f1rl middotiomiddot
Ph (pr fn) Ct 1Pvl()mor~)hlto -- r ~ gtl A 3 -~~~~ gt 1 i
-rgtvrnlgt~~middot11middot n ()pr t y t HrI1 ~ r hA middotmiddotmiddotlv-o Ir- middot~IJJJ )_ 1~t j t tIJa _110 JU ~ (ltrbull i~ ~~l 1 bull ~ ~) )-~
i( )gt (flnr~Oor ~1 ( d 0 It) 1 1 11 (rt1j cr l() Pgt7 h-rii1 (1 (J 10)I J ~~ J yen bullbulll- _-l-gt bull _gt1_ bull ~Jmiddot bullbull l J
t)ore were oth-er rntnm ocrurreyenlceo j n the ZeO~1fn~ nxsn
Potryr(l ~Id not flftfnenrc of i~hefiH~ 0 her 1(C~l1~t~~iJ)f~~ hut one
fl j~ (1irl nI _~ gt( tfil)cll bull ~iVYtll0 bull nh rmiddot r~elm] cl bull~ 1 U (Xl8)J f)f ~~ ~ -I- ) ~ IJ n frnm~c _4 -I h~ 1
ulel1 ine ~ls )(1()011 t in thltG TnnT~lni nr) )~in1middotmiddot (o11eetotl
bullbull I ~n) Y(~middotmiddot1El D~(lfY~lmiddotmiddoterJeePe1~ter(1 (01) 0Jmiddot+ _ 0 n 1gt1 OJb a0 _ ~ U ~~
of the clc51u11-rich vor1 wty of JYJnr)Dr11d1~f1nown Ha Twlyshy
sphaerite at he 3lv~fder 5110
e 1 TT r Ags2iL
NntLv(I ~J lver of fJrDccmtlnXIf Dr1 J fl ~ n lF-J rC00r(1 ad
111 1() oxjJ)jzed z()nl~S never 1 ore-bodi ns j l l ~h0 cehr-tTI
r~(~bull
~lhe t119r occl)ed in the ItIToni tn ()f-8~H1 ormnl71ona
13Jong vd til 1110 ~UvO hcJUlrm eer~lr~yri tE~ ~nd mn1~ol7 te and
JpYr h~ ~I -lBl ~V 11- 0 COO 0lt7)( cd 1v middot)middotmiddotp on)It -ti ~ ~ ~i_middot~ i tbull Oj)t~~~ ~f t ~l~) bull middot1 110 l_middot -lt- J U
were recorded G08snoP1rorrn~tmiddot ann cr~rrrtrus h5 F1 fil lver
Vf~ 111 01 ht~ve b (J (~11 l~(~ J)-0 J~tomiddot~ L r1 t110 ll-) - eT~ ~V()r~middotri n ~f tj) c Oonah
L
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
235
Spray and Dalstrttpfl minas n~ar the liloIence Mirle and
in the C010l1S1 North area (Ch1oride Lode)
Etibieon1tll Sb3060H()
Stfbieonite was rGoordec1 b~~ Petterd (1910 p 1Tl) aa
having been found lUSEal1 quanti ties in the 33r1tiah
ZeCh3Jl (Sprcgtsr) mina at Zeehan
h9711~~tt~ ~~n5540
Pettare (1910 p1~n) ncor3ed voltzite ttt the S11ver
(TaliHJ1Hnutn) CrOWtl riline [1fj rare globulnr Hnd lar1f11ar inshy
erufltations
=---shy
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
r2)0
(rf~crC(GT((T ~P1tT~1t()I~1T~~li~ HY~_ _~ ___ _loI _
An lnvest1grtl 01 1nto the compotJiJ~ion or S~P~iq er- tB
from the Ze~~h9n ~uon hes been m-ilde Ltl an ~ttrmt 10 ohta1n
~i11forJ1~lr5 Drl Ofl middott~Fi_~)1~rn middottr (~J ()t~ fOl~nnt~ jmiddot)P )f oren and to
He(~ j_f~~hcre is cmy evidence ofiempinmiddotcl~nre gr (1~J H1te hav-
J 0z~t) t(~~ d11rjll~middot~ 1- it~torl ()- ~~11( (imiddotrei) ~1 ~~ 12 o]omiddotf tern
(iHrrrture dnt~f~ for 0 l(r nulphtdo fyrtifnne hNt nlno be-m
011lt J ~liT- middotrmiddot~~IlmiddotLmiddot-~ ~J JI~eXlFli lteltl i~t) ~~ ~ i ~t h-hr~J ~ ~ t L lt yf~ tmiddot~10 SI)l 7ec1 te s il11(lybull
~emiddot 2~1 ~ ~) $TstieJn bull_-~---_-~gt- -shyfhc applleat1on of t11Q ~]YStorl Po ~~rl S 1 n ie 0 ll)f~t cal
tiT181l)mnei17 hapound~ fol1()fed tH~ eXT)HCinerrl8 Nuck of Kullel1f(l
( middott nS3)middot who doAt~1Pmiddotp1i ~1tt1 middotnl hqso1(~1Tt (1( 1-2 Pyj x-nrvstt17 ~ - J L~middot 1 1yen J (~ bull 1 t bullbull C) _-41gt- ~ __ l 0 7~ ----
corrr))i lSonstn the svatcm FeS ~ ZnS flera p~rrbotite Hnd
l( J11 ~ ~rHlL I ] lHi 1J1-lE1T)h -lertte hDvf~ ~ J 1 j_gt~ vbull J oA t~ -~~ ~~l~) tr()Jl (~Dn1f~middotitj ()fu _
t~)e aI11G]_elj~t(~ (~ln middotbe U((hl GO d -te middotY11nO ~o~ ~bE~middot O)ernUe pound))7
f~)rrnnijt(ltl of ti~1e C9 ~of~J~lmiddottJGmiddot lt~~)~nrnlJ1-e3 (jf~ middott~~r~ f~1~1_tcmiddot~~ ~)r1 oe
l~hif3 oytt0rn in (polo(LcDI t~oirnone ~ry are Tnovtdfyl hy he
~t() ~1j~ K1l11ormiddotud et middot1 (19Ejr) T_1
-
iJmiddotj~ 1 S
- (1 ( -e
) It ) t l middot1 ~t r(JvI 11 1~I ~ f ~ Jt 1 1 ~ tl~
~Ll()Yl (-1957) ColemD11 (1957) ~~ il HiJOn (1960)
AttEmrpls hwn nlsobon mnde to USE the system l)tJteshy
~JJln ~eri te GfJ a gao1 () iil lt~~)l t erzYiOueter i)1(~Ie pTrrlloltte 5
~~i- lH~( ~(~n1~C Or nb~middotHmt FjfqJrjlOJ oftlK) W)3 o~ t~rLH nyai~m
(10 fnnJli ilr11 11011 ()~ r(I1-111 f~1 TL-lCCi (1r~~)_tmiddot lo bullbull 11 bullbull ~~ bull ) J-Y bulll_ (J- ~t~ 4 I tl middotbullbullbull1
r~ ~~~ JII 1J11 bull ~~)0 pmnl o middot(1o~)middot6) lmiddott -JJ0~a111--J ~ Ln n~r~oM (19C 1) bull~ ~~~ ~ bull ~I
It 1eGH~ DyrrtoJJ pyri~-r3ph~ler1In tch j ()f in terest
In the Z~ehnn ores ~31 nee Dyrrh ol1tn oc~urs 1n only mlnQT to
-~I trctce 0lJrlOtUJts in omiddotr~middote8 frorn the restsin nnltt Cr~f1 t rrt~a oflt~- t
--
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
237
the area and is ahsent elsowhere
In this study of the Zeohln ores the oompoSitlon of
the spbaleIite Ims been investigated for all m1neo in 1h$
nr~a from wh1aIl suitableaamples coull be obtahled Aa
deocr1JHJld earlier in thin middotthesis the majority of them1tl-G1lEl
111 the ZeehanaIe8 gre now 1nacceaaHlle tJnd mOErl of thG
samples VNJlret therefore oollectecl from the tltunpa of the
millea AltllOUgb 1 t would- be- of irrterest to inve~rtigate the
laI~iatiol1 in c011Tposi tion ofsphcLlertte within incUvidltal
ore bodies this i8 not possible for tho ZSfhan ores
G1owth zoning was olnserved in fiornesFoctnens of aphalshy
er te trOll( lhe istrict bxt metSU1(3fflents of 1jhx iron content
were not made on tl1Gse apecilnens
Ant~~ Intholt1s rJnd $Julta ~tieal jI I bullbullU ~ q - _ 1 _ bull
Tha oDJplea of sphaleri te were inves1igated by two
cliffarent metluHls viz ~lectron-probe miero-analysia Gnd
X-T)Y povder diffrl1ction
~tH~ 8fltlrseJmiddotd-th the electron-probe I1ttoro-ult~ljrser
vera kindlycarriEHl out for the auClor by flir P ~chultz of
the AUErtralian MirHHol Developmof1 Iibotat)riea~ Adel~d(le
South Auetralia Elements i1etermi ned were tron codmtum
Hnd lllaugnese HefiUlmiddotmiddotta of middotthese analses are tihown in
Table 11 liot~ theurorSS dettiuwililiooa the sanrpl-eB were subshy
mitted as polishedf3ectlonrI110vnted in cold-seti ing polyentcl
reninmiddot and the fo11owing notes on iHla1ytjenl techniq-e rmle
supplied by Mr Sohultz
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
3()e c~-
the sarrlfJlf)s were uned as recelod withont cflrbon coat illg Sorne cioxg1ng effects were experiQf1ced 1lhe electronshynrolG ~ao 15 rrderons in d1amet(T nlotlueed by aT accelshyort1tlng voltlgo of 25kV and yleldilg a ~3peeim9n CUrICflt of 0 35tt~bullbull
Ineoich inBttwoe OfilE~ aCCl~rate ~3poi rUllilJ~reis was Tlde 4r bullbull t Cd ~~ 1 middotmiddot1 ltvmiddot l middot1)middotrmiddotmiddot O middot1t rgt~ J AJ~ ) ~t J _ Cl1 ~JCt phJi J_ t~-~lt 1J v C~Jo (t etdi k e i~ (middot~ilj~~ _J tru~~ ltt~
oheckH Irc f~)etalfJ were uied aa standf)rrls ancl mass ah-eo I- ~ ~~ 0 fmiddotmiddot ~ n ~ ~ 1- -to 11 ~ 1 ~ ) Q cbull rpv ll vlIt tJJ -lt ~j)J 11 j a V_middot __ middot~lt U L
Values 11uote~1 are aoourate to 1J05s of the amount jrenent
One obvicrU8 (Urmdvnntagt~ of the (-lanlron-probe technique
Uoed in thesemeasnrements is the range of tU1Dlyti5cal llll shy
nerta1nty but~ tho total sprsDd of 1rOl1 veJues in Gl)haleri to
from Z08han is nufftcJOfltly Inrge for the method toprovicle
fdmiddottlif1ecmt rem]lts rlhe great advantago lrl middoth1s method is
tho nblli1jY to carl out eJ~_Jlygtea on extrctloly ~3nal1 1UliMltishy
t1es of Jl)61tel1[)1 ~lnc1 in several of the Zeltl~hunsaxi)1les
aphnlerite ls not truffin1t1ntly abul1Jlant to Gl13blo ennlysia
1) 11 ~4 mAbull cl1 c vU~ 1gt lgt
1 1 ~J j t-cmiddotl(tmiddot of n 11)- bullbull j ltI f(jlmiddotmiddotmiddotmiddotmiddotmiddot 1t~on (1963)0_l~ 1 1- _1pound IY-r)- J - J1 ~ L -c Lt fti~ I ~ - v~ ~- l1) I~ -b
htlVe 1eI)OTtedthat 1TIOtli11UCment TIlde by themo~ thD iron
(11~H r~ nl p Jlt middotmiddoti+lciQit 104~t inff Ih~_ l~ noOiV middottJmiddotOfbull amp-pound)t 1 flmiddot 4 tenoh(~ J~~~~ b ~~~ ~IVl JmiddotY0 t lJ ~ ~J~ V4-i LtLJ1~~
lmiddotemiddot1 (1middot middotmiddot tmiddot0 +4middotd coEgtilJ lmiddothCmiddot 1(1 ~_ r_~Io-)V[tl) ~A tmiddotmiddot he Jit~~t[~~11 0 -C40-i jI~Vr~~ i us middot~I~OmiddotmiddotUmiddotlt f) t~ - shy
15 o 5~) flo1e lnneent Jflt3 No details of the m(~thod WElrS
glV~H1 in tide f)jbsmiddotiroct rcuort lmt Mr KJa illj~ma of the
JUlstralian H~ltjonu1 Univer~lity 11~1~1 rocently ~m(~cceded in
-rapplyl ng correcl1 on prlt~t)rtr08 tv c1octrm- rot8 mtcro-analy~efJ
rmiddot ~l1 1 it 11 h~ dmiddotTio ~l 1lt fHltrmiddotor( cr-j cO) 4of 1-1hmiddotv~ illOl_~Vamp iii C1middotbull~ A~ t~v ~V~middot 1~tr ~ middotttlt~~ J~lti JJc~i bull ti 1gtr ~Jmiddot u
mnjorityoT analyses by the technique cnn he qu)tei as
u tmiddot to plusmn qt Iy[ middott1 - - pt 0 f)c middotmiddot ) 1 A-CC ltlEJ --ti I hue BOilUgt JfiOfHH 11 n 1 bull~ ~ itJ ~ b kshy
11 hv~ brmiddot 0 ll v il ~middotl t b~ x111~ -lt1 ( Qet)ti lw Ci~~ I ~j~ ~ middotw ~middott bull ~A r~l bullbull iJimiddot~l U~~J~J J tf t~ -~ ~ cmiddotJ~~-lgt)t t 1
--
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
239
The romlla f31iOlJl1 in Tahh~ 11 ~Iere C011fdd(~re(1 to be
nrff1 ei cmtly in tB(H3middottinn to 1NarY-afi tho CX81101 n offurtbsr
l1rDlp1eE from w ueo AD It was not possible Lo Inve
f~JImiddot)middotI(middotmiddotmiddot4l fU ln1iI)W--O~i)~~1 middotmiddotXmiddotmiddot-i o~ omiddotu tmiddot tmiddottI pl+ on-middot)bull
middotmiddotmiddotb0l Ii JJi middot u ~J O(~bullbullbullbull t-t_~ll bmiddoty ~ tA 1 ~ rrl~~l-f~]
J o
Ibr) 1r_rQ oovdo (li-ffJlcmiddotj or- meJj)od l]U 0)] o~lldJ ~ I~ ~~J amp ~ -40- ~ ~~ ~ll l_~tS - ~t ) ~-~middotmiddotmiddotJV
lrlv~(~ (1 nC3) imiddot-tmiddotl r of ~1 (1(Hn) lCt l~1middoti r(Imiddot961)ta~J~ il Jt l J -I Hmiddot)J 1 H G W rA bull )rl (~poundA ~ ~~ ~~ ~t I~
hfwe 1emonsmiddottrated thEet aecrlrnte me~tfH~rernents of the unit-
cell (~dge ofSlgth11EFite provide S01HitiVEl m$t1BltIOm011ts of
l) OliA( 1middot ( Ckmiddotj 1 (19(1) middotmiddotv~middot~~ t 1itegt fmiddot01middotlo1JUI~middotv 4~~ lbullhJJV 1 U _l lt _uJt 1 Lfil-tv~~ l- U w~ 1 iI~
relr)ttorU5~li p betWtVmLltl~t-cell edge and compos5 tion of
flJ11t11ox~i Jte
a ~ 54093 + 0000456 X +000424 Y +0002022
middotmiddotnmiddotmiddotL~middot v y n C lt~ imiddott~c ~fmiddotImiddot-tl-tmiddot~ rmiddot Flti-ftJ~ l Q M Q~middot1U tj t~ VS~ bull-r i AV-i lIb v-t tmiddotu CdS nndMnS
t bull 1 ~ lbullbull bull ~ CIU l - ltC _ J JltinIrOltlii e ~ltr ~d a-t c -lhJo IH1~a_Cpgt1middoti d o eT middotth
~)~lmiddot Cl litmiddot (j n 10 ~~--r bull~bull )i 1~ t 1 ~ lf~ t-J - ~J- ~-j ItJ vLlaquoImiddot bull
~rbn un t-cel1 ea e LflEtnUlements of splnltlri tit] srmiddotlfljJ ea
1middot nV -bmiddotlmiddotmiddot-middot~( -tmiddot 1n no 4--~ fmiddotJti ~middotfmiddot-middottio11f~ ~(Jrn ~lAC7middot~4tgtn lmiddotC~ Ih~u iiOigt tumiddot~J l_~(~~ _ b1JV ~ t ~ C~-i IQ h~-~k)I(lII J q ~t ~At t~
1h~~middottffrU-J~~ -tmiddot~omiddotJ~ Ql~ CJl~r ~iI ltrvf 1 4 t 4 bull 6middot m ln ~i amiddotimiddotrni_~ bull(ICmiddottmiddotmiddot ~t--~ ~Sl-l~ l~ _~ h-H i 0 11n-lnra
nrn1g~nf$G f51tered iron j1X rntlirt1 on In EJC1) cse the vtJlues
of Qc- aole~113iet~ pound)1 ecwh of t~hJ li l1t1S meH~Jllred were plotted
llgainst the Iicleon ~ltld Rllay funetion (Nelson and Riley
1945) ancl the curve extrapolated to f7ive the 111111-0011 edge
value at 180deg29 The uncert111nty inhese mefiltlDlttements Vf~la
o pound1 ()fOmiddotSoil middottmiddot~)middot ne+rgt1middot -h7 1 tfT -16 lVmiddot~middot~middot-~omiddot htlmiddotmiddotmiddot]1I~ll -r middotmmiddotJ- u ubull J bull ~~ IiJ bullbull uVl1 )ltI~ v L Lov~ Ll vU ltcI_ c -
the l1llrrerImll poundwaroc of oev crc~l meruiurements of tJtc EVI10
ph)tOgI9ph
~
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
----------------------------------
240
A J flgt~ _ bull iB T1 11
Bl(ctron-probe micro-arlltJ1~ses of Sptlalerita Zeehan
Mine Polished
sectton number
Element
Ye vveLrht
Cd per cent
Mn FeS mole par cent
Oceans 1254 17 06 01 3middot0 ~
00oa11 P255 2 022 002 4) 0 AU6tral Valley P ~l~6 t 06 0 02 09
Zeehan Bell F 2ti8 50 0 3 001 8 hbull J
Sunrise P259 004 025 007 006
Sunrise P221 15 025 lt001 26 Lt Silver King 1260 1 1 025 003 19
Montant9J S1 P261 11 (001 002 19
1 t smanian shyCrown P262 31 04 004 54 0 JUYlct1on P263 08 02 lt0005 14 --)
~-
No 4 Argent P264 78 0middot3 005 134 f
-
~)
StOI1Tsdown P265 82 0middot3 lt0005 140 U i
Silver S1ream P266 13middot3 025 17 226 2l
Comrtock P267 112 02 lt15 191
Swansea P268 16 027 lt0 005 27 -
T L g P269 5middot3 03 06 91
SpTt1y P270 7 7 027 003 132 r-
Analyses by P Schultz AUBtrali~ln M1neral Development Laboratories Adelaide~ South Australia
~
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
241
The above relationsYdp between unit-cell and oomposition
demonatrat~s thHt the cell edge io dependent on the presence
not only of iron but also on other components in soljd
~lolution Therefore in order to cI3l1eul~3te the jron content
from unit~middotcel1 edge mensurEHnents it is necessary to knoVl at
leasi the cedrnium and mangane~3e contents In the6 c81ltmlshy
ations it has been assUlfled that the cadmium and manganese
contents of the sflhaleri te samples are equivalent middotto the
average values obtained from the seventeen electrorl-probe
analysefh frhe aven1ge GdS value is 024 mole per centt and
tlts 8verage MonS value ie 031 mole per cerJt Table 11
demonstratfJS that the CtlJdmium content of sphnlerite ahows
little v~lrjatfof1 in the Zeehan ax-ea but the varlatlo in
m~n~~laBe con~t i~ Eomewhatli ghr r1d it~O~1)CeH an
addluJonal SOilrC~ of error in tlh clcuLtlOJEh
MeaStlrementa of the untt-eell edges of elfJven aphalertte
SanilJ1eS and the calculatHrl FeS values lre listed in Tuble
12 frhe last two samples listed in lIable 12 ie spholerite
fraIn th() ComErtoclc ana Srray mines have been included to
provide a COnri)oison wi h the alae tron-probe micro-stnalysos
Ilhree figures are shown for each of these samples these
~re (1) the FeS valu0 en lculated on the baste of the nv0rage
values for cadmium and mang~meae (2) the leS vHlue 081shy
c1Jletpound(] using thE~ actul c(Jdmium antI mansectPnese vallles for
these sFJmplpE1 rneasttred by electron-probe (see TFtble 11) and
(3) the FaG value from elE~clron-XJroba measurenlent (see Table
11) The two calculated values for 0 1 srnpl Q 1 f~ are 10
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
- - -
24middot2
reoHof1able agreement Vi th the elec-tron-probe micro-shy
analyses t and are withtn the range of snaly-tcal uncertainty
of the electron-prohe measurernan1s
1 iJ31BIt
12bull
Measvred 12nit-eell edpe valtles and ci~lcllhtted iron eontents
of sphalerite Zeehan
w r n I bull iIMIU J ~II a 4A~ 1amp tli 10 j J I bull T f r
Mine Corresponding Unit-cell Caleulated Polit3h(cl edge (1) FeS mole p~r
section cont nmnber
bull t8 bull -li -Dorie 1333 54190 178 Sylvestier IJ20 5 4203 20 6
I ) 31113088 54180 156 -
13ritannia P332 4178 151 3f S tonehenge Jc 54130 46
Grubba 54145 79-335 Colonel orth (Tlrwiwny JoImation) P345 4132 50
l)espatch P 310 54150 90 SweerH~yts P368 54205 211
If)COI1stock middotP267 5 4196 191(177 19 1
HfSI)r3 P 196 54175 123(155 132 )
ttrIgt ~~ bull Eh tmiddot0 + 1 1 ~~ t 0 000-r erL 1 A
C81cul13teOI vHlue on basis of actu~l Cd and Nin content of 1~hese samXlles
Values obte5ned by electron-probe Jllicro-analy-ei-s
~
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
------------
243middot
Internretati on of results bull -Ill J ill I bull bull bullbullbull It ---~ shy
The sriationtJ iu iron-content of sphn leri te in the
ZCfchc1Vl area mpoundlV br~ i Ylterilt0f1 by me 08 omiddotr Fintre 3 (fro ~l lt1gt 9 (11 ~ ok l~ - I -_ ~ - IiJ
31ms ~2l1d nHrton 1961) in ~onjunctioll Ni th the theoretical
nnd expertmel1t[~1 work of J(ullerud (1953 t 1959) t Dnrton and
middotmiddotmiddotmiddot11 middot(1 ltcd~ bulld C-l f n In [k~i]lnrmiddotoViu (1961) bull(1 Q f) v_ c ( ltt ~ l l ()
900
Sp+Po+v Sp t L t V 800
lOO
600
Sp Toilitp + v TIDe SptPytV
500 EXPLANATION
~5Pholeite
Po pyrrhotite 400 P y = pyrite
L = liquid (mostly sul(ur) 300
V = vopor (mostly sulflJr)
zoo
40 30 20 10 Mole percent FeS in spholeile
17 I 1 D J~ lf - filJ bullJ~ ~ Compost tlon of sphaleri te in aqttllibritun wi th is
Vmiddott~middot_~I- O1gtS ~11middotmiddoth~gtt ~ llJ h-- nvmiddottbull1 ~ l1 t - Jrl - lt~ (fmiddotro 1J(~ til~lo b ~~middot iJ -~ e LI U tAJ
C ~ l1 Tr c tot cmiddot 1middot or 1) JJ3 -middotL ho O1 J
fCJ fnctors COIl trol1ingi11c~ iron content of Behcgt lei te
in etlililJriufli wi Ch pyrtto a1fj (a) other elementrl preent
1 gt-1- middott-)nmiddot1~~middotCI 0111 Clnhmiddotmiddotemiddotmiddotit (b) 10lt11 T~IUJI_ h4(~i Q bull ( b AJ~ Jl tJ ~J ~l~p 1~ 1-x J Jtmiddot~~ ~~1~J~ ~ ~
~
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
244middot
(c) te1Irperature ~tnd (d) activity of ~iUll)hur
In ttddi tion tD iron erne11 afi1ounte of other elements
may substHiute for 2~ine tn sphrderi te rha moet irnportcmt
of thl~Ge other elements are oac1mi urn an1 nnmganese but
ld8fltuth eobrtlt copper gallimn ind1UllJle r d morcury
molyhclenwi1 slIver and tin a180 maybe capableof subntit shy
uttng for zinc Previous invcJ igaticma (eg Frykhmd and
Fletoher 1956 Sime and lkirton 1961) have shownth~tt pure
sampleD of sphQlerite COlrtfdn very low fU110Ults of the-se
eler~ents bull
Aeeorilingto Kullerud (1959) t ClxperirrH~ntCl work h~lS
)olon 4omiddot11tmiddotI uxtr 1Jr~middotn(n of 2 Tpt rftlt bull l bullj~ lemiddot o~ middotULlf tf - middotmiddoth~ - ~~ middot3~1 VUJlmiddotn c~~ 1iO ~~-ut-Jj ~
~Indor mrru1gonese has no td grdficant effect orl the solubility
of fr(H1 in sphtllerite
rrhe effectis of total pressure temperaturel1c1 acttvity
of sulphur are in1ierreltited f and hcve b~JEHl cOnpound3jd(7red by
c~~ 11)j~ )nl nprton (196middot 1 ) bull IJ 1 ~~ According to )Jms and J3rton calshy
cll1atj ana hoye ahon -that tOtfl1 presmre holS lt ttle effltct
on tlw ir n contotlt of Jp~r~aleritlC) tn equilUgtrlum wl th pyr1te
for a givon temperr~tule anfl flctiVlty Of sulphur If theeeshy
cgtncltmi om) rjl ~OICi middot1 ~ en1l be assU1lf1 middotht the variations~4- ~ 1 ~ ~ Ai od
in iron cOfltient in sphnlerit( at Zeeban nre lt1ue lo trH
cornhined erf fe-ct3 of t1Jpnrnbure fmd actlv1ty of Bulphur
S11113 and Bmiddot~rton have aIs-cl clleultted thrli at con~rtant
t nn-Jpound1 P tttImiddotp ii 1middot1~-l~li-1 middotmiddothIttoe middotmiddotmiddotrrimiddotte-Qltlt3l~hmiddot1C-middotmiddotmiddotpr1 middott cmiddotmiddotr)lbullj liiy ll lt v fi~14~ 1v -iJI1l-)J ~
(see Flguro 3) an incrc2Ise intho activjty of mlphtrby
two order] of mJlgnjmiddottude decrease) tih~ molecular percsntoge
of FeS in Bphalerite by one order of magnitu~le 31ms tlnd
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
JlIt4)middot
Balton have pointed out tbnt since the range incolJposj1ion
of 11eS in sphalerite is only about onc 01(1131 of 1IJngnltulle
(39 mole percent at [)94QC to about 3 mole percent at 200degC)
whereas the possible rmge of acttv1ty ofsulphnr is many
ordorn of magnltude act~lvIty of poundu1hu1 is a verjr important
hImiddot t tmiddot i bJvarJa e JI1 PSl1 e-spl1~t er vEl as 13 em _lgC~h
rrhe iron conterrt of sphnlerite formed in equilibrium
with pyr~tetprovldes rt minimum temieraure of formation of
the sphaleri te-pyrJte asHmblge~ 1~fhen the FeS-ZnH s01vu$
curve (lcnvcr curve in Pigure 3) is USE1l1 as Et t~W1IJBrctl1re
tndicgtor SimilarlY~t mHxil1lum tfFrperuture In obtnined by
usinthe curve which ShOWfJhE cmnposi t on of sphalerita
existing in elui1i brium wlth Ilyrite + li c1uld + vapour
( r~ J) fllt c4-pfll teITmiddotAromiddottmiddotlrmiddot WJ middotthmiddot l n 11ri+A JLu ~~lt J ~~1~i lt-t ti_I~ ~ ~~ll ~ bull 1_amp_- ~ tV-f)~ - ~I-- tttJ
at whi(~h ihe a1)hl11ex~itle-pyri to HSfHuItblage wtlsformed cHnnot
be specified vii tJwutfurther krwwlod~e re-~~tr(1il1t ttlG activity
of JJulphltI a 11( time of forTfation
l ~tcmiddotn (-f middotmiddotllmiddotimiddotmiddoti~nmiddot 1- - middotry middott- rnr Thnl_loll lJeQl Jbull~ e ~ l bullIX I De lJweeu iJ 1 bull1 SF
erite is clearly of cci t1 cl importance in [1lte apl)licnlion
of the oyf1tem Fe-Zn-S in gltHJlot~ical theJmome-tty Fgtm11ibriUIfi
in mrtV1lll n~JT11 afKmiddottTll)hlge~i iD difftCll1t to prove but
it is often afsumed for coeXisting rdllCIflls
B1middotmiddotrmiddott- 70 ~~v~ rmiddotmiddotmiddotmiddotmiddot~t middot~)t 1 1gt11f80middot11 fkmiddot-d tltHl (1 0 1) 1lt3 e -I c f S1i bullbull 13UgteuroIe~l ylqlr~I
I 1 e n e j middott- 0 1middot jmiddotl~r middotjtQA~I if n -~middotjmiddotmiddotImiddoti ( bull rJmiddot n(middotr~middot) ~ (11 041 0 gt1 -t ~J ~ -1 IJ -il )~ __ tmiddot f~lt G(ltmiddot_ ~ J ~~ - bull ~~ J ~ gtt
yrttc then the kJphiimiddoterlte is in equjlibrium witJt the
surface cf the p~1rj tee ItH term Ifsurface errilihrium ~la
us ed 1) SimrJ n(l lkltol1 to describe~hc cxten t of equi 1 i br1um
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
2~16
hetween the minerals in sueh n 1~j tut1tioll Since it 1a the
J~~~-~lmiddotImiddotmiddot Imiddotmiddotmiddot i~middottt- 11llmiddoti-t1 j1 jVl1 bull 1 i tJmiddotmiddot nmiddotmiddot~fqAf~tJ lfImiddot h 11 emiddot1))11bmiddotr-I101 y~ u_ ~lf~ ~hVV~A~ _ ~JO
middotmiddotjmiddot 1middotmiddotmiddot ~ eftuim11tmiddots for Ih lt11 -1middotmiddot oJgt y 1_ t~k - t1 lt Ibull~j ~ampCi(~_ V c (QtlJS _vc~l_lvlt t 11 J~-ut
system in gE~olc ioa1 thermorne try would be s~t5-sfied
ThQ convel1tlon~11 Intarl1Jetation of the textureJ relationshy
sillp between prri te uld sphDJeri te in th(0 Zeehan nrea
j ndicate~that the sphaler1 teoCcardes a laLer posi tlon -than
pyr5 to in thf paraiE~netic seluenee If th1El in BOt then the
ltCt-h middotj--middot bullbull ~oul a 1bullbullbull 1 rmiddotmiddot Jlb middot1 Tt middotthmiddot 1rdC cL c 1 I) e ( [hC 1 middotlA Lb middot1 EL11 bull1 bull Tl lt1nl 1 1 J 0 JJ r~
It in eanenMnl tl119t euJfici(Hlt pyrite Wf1Sireoeni for
tho sp~t3eritG to hav~) become srfLtr~1cdmiddotith iron at the
tenermiddot~t~ure a~J YiIrioh it NiS depost ted Pyrlte is not ahnml-
Hnt in ftll mines 1n the Zeehal1 area but care was token to
Ineasrtre the 1 rem conlC~flt of only hOSeurolrlp1 i --middot ermiddottte snmples
cuntdning ufJJocie(-c pyrite
TTH) sp1Lmiddotterjte Sillii)les ljsto~ 1n Table 13 omlalso
zhovm in Pigurc 4 have iron contetlts I3neing fro~) 006 mole
~llor~l~lt~jt 1 C~-) laquomiddot~TmiddotIltgt~stIJv- 1U ~ 11 to 22 6 1P01lt middot CCgtitmiddot~i -(bull Gli)t~Q V 1lt gtQ1~ ~Oin) f ~ ) NV jJt J
t~lm( lt~4J-_1 vmiddot middot ~middotlltmiddotmiddotI1Mmiddot~1middotmiddotl ~vv ) o1bull tJi 1 l_~~~L~ 1 (4()t1 11 I oF
hV4tv~ J ~P bull v lJ tt ~ _i liP~ T~~IV+ 7-1 J~
4 23(1) IQ
loporteHl tht the pnaxirrrum i3IJ10unt of iron Cound in sJhnleei te
j - h v imiddot middotT 1- ~lmiddot~ r 1lt) 5 tmiddot 0 C )n cmiddot middottVI lt rmiddot cmiddot 1 1 1) ~ l( ranG ~11Ei8 - 0 r_ Lcl) e tmiddotor euroH
1ie(~ + )(degC rijn ~JlC) yr gt2 6 mol (~TlArCf~nj jIC frmiddotI +1J J1wi cl- 1tmiddot - bull middot01 Vff vv 01_ - ~ ~ _ J- ~lt _ ) cl V1f~
Flmp1e frrF the S11er ~)trc~mDJline is ihersforo hLrher
thfHl)iho mUXiml1fJ fiGure p)s~Jtble fox a pyrf tE~-tTphnJ eri te
~tsclrtblHimiddote but t i thinth rmwcof ~1llnlJmiddottieal u1ce~(irdnty
CL 11 r1r l~ ~ middot middot1 cmiddot 0 4 lr t- nl ) 1middot 1 01 - e~c v i- 0 ( t~ort)~i bull 1~J ) tlV~ _iji~ ~~ ~ bullbull) ~ ( l~ r~ JL JlVIJ 1middot~RJ J J
J ~middotmiddot1~pm ~~ 11 lt +_ rCgt bullbullbullbull1-1 emiddot ~_V(pi I~) pmiddotHraquo_ v _ 1- gt1ld Wtllo pv Q I -J nll~~ 1iiJl~ tJ ~~lJiJI slihtly I
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
- ~4 0Ilimiddot
hi her than WGuld expected bUt are aeain 1i t in the range
of HYwlSjtcal u1cert dnty Themiddottjemernt1Jres of formation of
f~It1t ~_ I +t-e ltlt1111 liG~1 1ltgt f~hw~ V~In ~~ 13 ~~- 620OC~ ~1bullbull1- t lt U _ in ffohlltgt Q 0(~ L --gtj 1 ~
templfJtur)~ ob~0i n~ fmiddotom 11o~re 3 for o1~heIlhe ~ ~ ~ yenJ ~1 I bullbullbull 4- ~ ~ - ~~
S-~17l ~-es ar~ leGEJ GrH~(ifiCt anl Dhowr cono1(]ercble n~e
between the maximum and Dil1imnm tertlperatureuroA for each fipl1al-
erito s1l1ple- eg eph3leri te frornthe Brita1Hlia Mine eon-
t~dning 151 mole JereeriTli Jie~1 cOlld have fOlI101 at ~~ny
-t(middot~~ middotmiddotmiddotjul1 bmiddot-t91~ Jl(100 n~ 740degC l~ninO n middotthn -v4-yu ~ tf 0 f t IJ ~~ ~ tl ~~ i1 il ~ J (lmiddotdtl ~3 c roJ -fr-J ( j ~ J- tJJl ~
~~ 611-~-r rlt1f~e8()toOr- th o -ii tJiltAmiddot bull ) Tbe pCsuible temperanre for thH
variO~lS sampl(poundl are listeil in 1a-ble 13 It mun1 how(3ve
be remiddot~)liaedthr~t -these tempElrfmiddotureo ore ho~Hed (Hlth-e measured
val~es of FeS and 1 f allowance were raad 0 forhe rn~1rgin of
fU1f-11rttcal uncertainty t the possible rGnes ()f temperflnlc
on]Ji be incceuroFIsQl even fur~her for each ~mmple The unshy
corLrlnly of the temperntruE a~a Is again fllrt-YH~r incresed
hyi_ c 1l~tIl+middott h ll1middotrlt -f4 m)1lrflnJw t 1 1 l~rmiddottmiddotmiddotmiddotlgt1lt1 cmiddot nmiddot6middot6middotSmiddot)- hmiddotmiddottf-poundl~ J~r~ 11rct ct_t (19-4middot J V JI middot
the feS-ZnS solvus curve cd ltullel1lJl (1953) eouJl he in error
i2tnr1 ls in need of further tnvet3tiJ~atione If this in f~Qt
ljhen 1~h(i) Ilm1lltrnum tBrniperat1lri~s 11 ated in Table 13 could be
-llib j eetto revision when further eXIi(-rimen tf11 work i 8
enrriec1 oU nn t1w Fef-Zn~ solvuH
)
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
- - -
248
TTiB~~1 ~- uJ~~ 13rd bull
Iron conienta fH1ltleatimated tenrperaturea of f01fltttiion of sptIBorita Yeehan
~~ 11 IS_ I lWW rm--
Mine
J_ ~tbilf
Oceana Oonah AUf~tral
ValleyZeehan Bell SUl1rlf3e Sunrise Silver iing Montana 81bullbull faemantan Crown JUYlctlon No 4 ArgentStormsdown 811ver Strerotl Cornatoeli Swansea T LJj SprayDoric Syb1ester Soas Britannia StonohengaGrobbs Coloml N01~th
(Irramway Formation)
Polisher section
FeS CCllent (mole pelcont)
nurnb~r
tllllilllr~j JiI a 4 w 1 ~ AlII
254middot 255
)043
256 09 258 85 259 006 21 26 260 19 261 19
~62 4 263 14 264 134 265 140 266 226middot 267 191 26B 27 269 91 270 333
1)2178
320 206 325 16 332 151 352 46 335 79
345 50 Despatch 310 90 woeney f s )68 21 1 ~
it- Not corrected forpresrncre
~~tirmtec1 tmrpE~ratlJre
of forrm1t5on CC l )11 f1iurtlum iltflaximurn lIlli~IIllllTT 1 _ d l~_
190 605 245 630
lt100 560 355 6g0
lt100 400 190 595 155 590 155 590
220 640 125 10 460 730 475 735 620 620 )80 660 180 600 370 685 455 130 550 685 620 620 50 730 490 740 255 630 340 675
265 635 370 685 620 620
~
~
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
(5A) TASMANIAN CROWN (lA)JUNCTlON bull
(178) DORIC bull(Amiddot3)00NAH bull (90)bullDESPATCHbull
(14middot1) STORMSDOWN -~ ~r
-~~~~ ZEEHAN bull(13A)NdegA ARGENT
(226)5ILVER 5TREAM
bull ~i1 )COM5TOCK E (19)SILVER KING (15middot6)B055 bull
~
(151)BRITANNIA bullou (13middot2) SPRAY bully(~p bull(9middot1 gtT L E
~6 h bull (O9)AU~TRAL VALLEY
to bull (5middot0)COL NORTH ( 8middot 5) Z BEL L (A 6)STONEHENGE
(O06)UNRISE
bull (26 ) (79)GRUBBS
(2middot7) SWANSEAbull )
SCALE (3O)OCEANAo 12 1 MILE
I ~ bull
Figure 4 Map of ZEEHAN AREA showing location of mines and iron contents (in mole percent Fe 5 ) of sphalerite samples
~
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
250
1110 lron cnntents of the 8p1~~iJerl~Ge exhihi t 11 pattern
wlJich is g0nerGily systematic 11 th respect to the gcogrilph1c
lac-uti on of the rniJEHJ (see Figllre 4) t although there are
some local t rregulari tj O~middot Spha erl middotte SJ1l) C~1 frOIi1 mi nes
in thf~ woa~prYl ~ oJ oJ ihe middotfieldL ~ J hJSlmiddotl~~omiddotn w~ _ COlflmiddotto(fll~- I ~ J i9r( 11 ~ (~i] ~ri(j bull ~lntl ooQk
Mines ) rtre hi(~h if iron content while 13pha srite snmplas
from mines in tho northeSfJterrgt cJstern and nouthern marshy
ins of he ftcld ~1re low in iron content TIIG mtnlB with
3ph8~ erica confjdit int()rr-gtedtate vrdues t3re locHted in a
region occupylng the cen)rl part of the fiold and egtetending
east to include mines in 1ho~ueen Htll-ArgeuroHr1i rlx area
The vallatj on within this i-egion of ilter1nedlate values also
ahows a patt~)1middotmiddotn which is generally syamiddott(~malic The only
Slhn1G1i te sample reprenentinp a mine wiihi11 the HeemHldrk
Grtnitc in J -rOJ m ~ 1~Tlmiddot~1middotmiddote (100middot+1uc~t rJmiddotOlrA lj-telyrhnt ~t imiddotenemiddotyc f S ~ (~ AJJ~A ol~L _ I~
2 milea nOlth-e~s of Trtal Hnrlwur) The iron c()ntent of
thts sam gle was measured at 211 mole percont FeS
BeClause each iron eOtJent does not in m08t cnses inshy
dicat() a specifte teernt11re of fOmation but iu cad
provi(le~3 a range lHtween mndmwlJ an a milll1mun values it is
diffic-ul t to intGr[Yt~e-l the recn11ts from the point of v1elI of
temp~)rrrlute gr9Jl)onts The totel p(l~mible rriincr of tetpshy
erg GUTS of forJllatj on for spha eri to in th(~ Zeexul area is
1000 ( or less) up to 740degC Wlitho)t some ImcrwlecVe ofpreshy
Vt~ili ng sulhur vapour irretsures 1 ( 1B no t poaoible to make
aJreC1S~ler(]Ieta~ion of the thenYU11 11uttern of 1lH) ores
I~ is useful at this atege to CODEddcrthe Norl of
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
251
filc~ I1stry anrl Kennecly (1957) t Sirns and Bartorl (1961) and
Jmiddotgtrkh (19middot(~3)Lftt gt t~L1 Vi bull
i middotIiitr ~ v 1 (0middotmiddotmiddotmiddot ltj) 0 1 t 1 r rlJ 05 bullr nt lenney 1middot ~~vo ebull na L--L1 l ne
aSfr1bl~)ges in the aystems Cu-ITe-S Fe-O-S Cu~As-SPb-As-S
(l 11) ~b 11 lr Omiddotlrmiddot nmiddot~middotmiddot(middot1 l~ltgt8e fliO rnmiddot on middot11 b1l cmiddotmiddotfr1J~ J -r) -u Ct1 q th) Pl VIoJI uJ It 11 t(~middot ~ bull ~~I~)J ~_) lomiddot tl 0 r~~t l t I
ObEHu~velt1 seqtumces of miner 1 a8~lemblngcs in vnrtou8 mineral
dep)oi ts The phE~ae dienrams of McK-instry and Kennedy
demonstrnted middotthEtl the trend of crrstallizatton of the mineral
rlf56pr~b18gZS WitS inr1ictive of nn increDfH~ in tho Chemical
1potentl~31 omiddotr sulphur 111 ho systems mcKirH1try and Kermedy
~OJggo~tc1that the most le~I~)omlble oxplanatiorJ for this
would be a simultaneotlf1 decline in bo1h teTiA3r~) uxe cinCl
partial pram-3ure of the sulphur
j q nl ~rton (0 1 taJ J C (~ - _l)~~ - J t in a dctDiletl EIWly of~T V
S~plDlerltlelvmiddotarin asscmblc~ges in ores from the GEHltral
Clts district of ColGrao f sxwwed t1e l)rSSnee of a correlshy
atiC))1 t)(~tW3Em trol content ofth(~ phaleri tf3 and (he zonal
arr~Ul7(~ment of 1110 ores intlw area Although Simsand
Harton vere aleo de~ltU ng vjth sph~Jerimiddotte-pyritB tlSfOffiblages
givirv a consljernbl rnge of middottcijyerr1tiure for 0GCl1 81)hl1shy
eri te SrWlLle t11ey 1erc~ ahIe to 111rwe moro ro~Ttrj(~tiVG
lip11to on these ranpes by concidertion of other rnirH~rnls
irel1H3nt in (ho afjs~mbltlges 8t1r1 aIDegt by BCr meBSUrefiC(mts of
tOEllNl C1re13 of formti on fr01 fluId inclufdorH1 in 1i1
middot-1) t l~-l -l- ~ Tll 0 middotmiddot~middotlC I l~ ~ 1Y ~ 1 1 0gt0 C f bull r j rj-t -i + ~ i hQfr(ampJc~~~~ u~- ~ ~jJvt~_middot ( J f ampH() ~J(lI~L~ fLt) lJOlr i ~middot ~IC vit
j-gt-c ~ [r] ~ -lj t Tt 6lrOOC Iqc Upel to nlmiddot3clP on Ucr~t-i~J CjJ bullbullbull 1 bullbull _ ~ - bullbull 1 r ~- ~ - bull C~oJ bull i -lk~
li r~~~ t t If 640deg0 )1 lbull tfn P lr1 J_ if~ _ fmiddot(_ijtlCJ-_tio L1 0-4J ~- +lif ~ tl l ~~ +-~middotl~Ubull l J ~_ -0 ~~
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
252
sphalerite in fhese f3amples By consideratlon of thE d18shy
fJiJ(iaticm curve for the enargite~tennantiie +8 reaction2
3111117 and Barton were able to place fUrthor rm~middottrietive lirnits
~lJ riilGlf1e of the tempexature lang~s and WtJre also able to obshy
ttill information on IrevailingsulphllT activimiddotty This di8shy
socjntton CUlVEl provides middotthe approximate relationships
between temrerature and ae 11vi ty of sulphur for the enargiteshy
tennantita reaction Where the pyImiddoti te-spbaleri te alselJibllgea
were accompanied by enargite or tenryanttte the possible
temperature range provideOby the pyrtte-sphnler1 te assemblage
was reduced by cone11c~ration of lw enargi tiG-tennantj te curve
As a reaul t of lttheir investigati ons Sims ~lnc1H~1Xmiddotton concluder)
that the l1pmiddotu31erite in ttie Central City distrJct WHS deposited
over a terklerature range of approximately 620degC t in the inner
zone to approxirnately 150degC at the margins of the onter
zone and they also tnferrecl a decrease in activity of sulphur
from the central to outer zones
I1arkhartJ (1963) studied sulph5de mirwral assemblages in
the ores at Jlount Lyell riasmania and suggestecl thtlt the
trend of CIjstaltization of tho assemblages was one of deshy
elini-t1g sulphur vapour pressure andteFlperaijUrih
The work of jVle(in~r(ry an(l Kennedy Sims 8n-d 1lrton and
Markharn shOllld be cO~leidEGed when making an interrret)tiol
of -the v[ltr1ation 1n compof3i tion ofaphftleri te in the ZeehRu
d1strie r11e most reasonable int~middot~rpretation ifj that the
decrease in iron content of the sihalerilo from west to
east was controlled by a gimultaneous decline 1n both
tetnperature and Dctivity of flvlphur ---
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
253shy
A much Ji1middot0re Ieiailedmiddot h1vest~ig~~t1on of the varl8ttons
y Armiddotm)omiddotmiddot~middott) 0 middot~middot1Tmiddotimiddott rrnrt _lmiddott- JnmiddotYln middotrgt middot1 tL_~( ~middot middot~middot~)t j-J Jf~ i4 J~ igt~(3~VJ_ ~ t _1 1iy JJ~middotJL-4 t Cf Af) (li
-Tea~m1 b(d carrled out by rJr K Ih Ydlliams of the
AUBiiralhul National Uni VErsi ty tlr WLlliams is employing
u ClI J tuthe electron-probo ann stortdc absorption ~~ bull hmi OP c rind is
applytng (wrrectjiof Jrocerh 3roB to obtain reoultfJ of grerJter
ElC(Ul[(W ihetl those quotelt~ b tti0preseu furtor Al-Morlgh
lVII Wlllit1xns f study to not yei complemiddotte the reoiJlta to
(h~to have apPBrently cordierilod t~10 mTeroJl patGern domonshy
~ 4 bull 4- (middott 1 ~ ) bull1 VI ( bullbull~ ~~s c (~f~middotl i7 ] )u lJCb 0 11 t~J L u E- jV_~ Imiddotjf bull Iigt~ bull It is anttcipf4ted tIlpoundrt
i1 ~Yjl1middotmiddotf ~middotmiddotmiddotltmiddotlt ill ovl dmiddot r11 4 + lllmiddot~ middott rnhtI lrmiddot roIA iJ middot- e lt i e uC vlJ tU gtlt IImiddot
nnd 0ould leS1(i to inioxJeuroJstlnn goooholrIieal COlflsderatj one
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
iq
il~ ~(11n~Jbull k r~ -W middotogtl~ ~ middot~t~Umiddotemiddott - bull j )nr]-11 ~h ett t~t~
bull bull r iMP I I
~rhere is no r-I)parent corralatlon between -the iron
COl1tent 2_n(1 cadmium or mani~)nese corlt~entJ ofihe ophalarite
lnthe Zeehan BrOflmiddot
fl~he aoluJgtiity of (~admiltln and mL1nBGnese tTl flphalerite
bo-ih inereaseVll th tnerea(dn~ temperemiddottlllelf antI approximnte
cOlTfjlatiolis beiween irlm and 1ntngane-se hnve bNHl demonshy
rrtrated by Flyklund and Jlletcher (1956 StrtJ Wine in Oocur
Cl1leoe di1rbrict Idaho) ard Sints and Darton (1961 Central
ltr t1tr-4--middot~t middotolo~lIomiddot)middot middotlt ltgt (1qf1t=) -IIO middotmiddotthfCl- thl(loC __ tJ _l~tltbamp1 t middott ~tu _y~Ct- LiJ _ J t Imiddot_~lt-middotmiddot ~ bull ) fj
~~(gtl~middot ( fmiddot~lI Af gt1-- Ij ~ -frli1 tltmiddot01-__ ~ 11--111 l1 C nr~~l ULlt-ut li middotftmiddottJL Y ( ~ i~_leh~-1~~ lx~ L~ ~trl ~T~ -t nA~ t )10 bull
deCreaH(H with incret1JBing ztne eontent
rhe cadmium oont~~nt t~f the Zeehan aphnJerite is
essentially uniform (see Figure 5) tpound10 mangnnese contont
is generally low anB 01lowa 11 t-~l( var5ftio-n- vii th the
eXC(~Tjtlon oX splHl1eri middotte frOlti -the Silver SkiLoam and T 11 E
)lt111
y 10lt (MAa01iQ too r~51 18 6) It cU1t therefore (HJrl(~lu(]e(l thfltlr-i) ~ pound v h(~
wUh thepo3nible oxcelrlion ~t manganese 1n thn Silver Stream
ano rLg- sp1181erUe oadmium and manganJle cH_d_ not
rcaeh eqDilihritull conc4-~ntretions snd the (lintrib-l1tion of
thefJe elememts in s~er1te itl the Hrea vn~) 001 c0F1trol1ed
by~teIp0r[rttue_
shy
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
1) +gt O ~~
Qgt shyt)
~ shyQgt Po 06shy
-4-J cbD 04-middot
r- (])
~ O t 0 U oP
20
18
16
14shy+gt ~
(]) t) 12 ~
(I)
P
-4-J 10 c bD
oM (I) 08 ~
-
06 ~
~
040
02 0
o bull 0O o 00
bull
bull 1+ h ~ 10 12 14shy
Fe (weight percent) FIGURE 5 Cd content v Fe content of sphalerite Zeehan
-
2 4- 6 8 10 12 14shyFe (weirht percent)
E~QunE 6 Mn content Y
Fe content of sphalerite Zeehan
255
~
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
256
Other snlnh11 Cl mine~41 arHJemblaiSif bull
As descrtbed above 31ms (lr)(l Bar-ton (1961) used the
rTIoltirw point 01 tJlU1Flntite (640deg0) to pIaca an upper limit
(~- J~lI t(rrmiddotT~r~ltmiddotu~ of port fl 01 orc hllttgt ~ )It ~p] bull t1J d AinS dl~ t gt middottigt~L~tampG tmiddot Ht~~ amp1 CJampo~ bull~l ~rjmiddotQ tl 1gtJA JI~ ro
mjrH~ra18 cOiltinillg tennanti tee The rnel1i1ng point of
t middotmiddotdmiddotmiddotjjlmiddotmiddotmiddotit ll 7vc-n by 11r ~ gt nnr1 middotBmiddotmiddotll(middoton (1917) 5te-degC Cc IclCu ~_ Igt eJ bull hmiddot nl -1 e] 1 gt1 t
but it is not rnown to Vthat extent thi a f1gure W3rJ)) as a
re~nJ t of snbsti tutionof elements such HS iren zi ne ann
silver i n the tetrohedrite lsttice
lt iNould fwrmn11y be difficult tio rule OutlhEI pOGs1bshy
111 tythat tctreJH9drt ie or tennJlnt5 te could have crY~3tal1ized
froT a sulph1cle melt Slms gntlBartc-n regnrrled the occur-
rmlce of tonnantJ te in 1ihe form of Nel1-d )vel01)e(~ crystnl0
project1ng into vuc~hs ~lJ3 evidence that the tennrfnUte tn
$ bullyen ColOn11 0 blrrI 64(1degCfmiddottl )0) Cmiddot l~4r middot hL~] Cl -T ftu~l-l ~~dtAt __ rOgtrn~l~llrl~jl Ut f bull( tI 9lt
letrlt1hedrite is common as alMlnor co DHtt tuent 1 n ore u3)JTples
from the majority cd the rJ1~ in th(lt Zeehan are but it
is not posslble to irecll1de the posstbUJty of soljd~fjclltion
from a ITI()J-j Dr HO I i~1arkhamof the Unlvcrsi ty of New
South-Hales has infoliYledthe futhor (]Jars COIPf~) that
Dtgtn13 r l lttil 1n ~~ 8 0lt QJ corn nmiddotmiddot k 11111 CIf Smiddot tv JJ ~-_Jtn ~ 0 J1JfL~ Q L bull id 1t U ~ ~) middot 1 Cilj 1 l ~r
Show) no textural ov13 once oiUlelting yet those ores are
rrmiddotumiddot~f)] Jy jcetd f1~_-t ~~ ut~ -iJlOmiddotV(J 600oe ~~i3~bullbulll 11 llvimiddot(r oVWYd~ L ~c (middot[J1Imiddotmiddotmiddotigtr q~)~~li z t JkUlr~
1956 Kvl1CTlld 1959)
It would therefcre bf dangerous to attempt toplace
limits on the p0581b10 tmi1Jeralu1ea of formation 01 Zeehan
orBf3 on the h~tis of the tYlelt~ing Joinmiddott of t0tr[hedrit~
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
-------
257
rremperatUle data for other sulphide mineral asaembl8ges
have also been (wnsiqeroti to sea if t t is posdble to
df311ne more prectsely the temperntures of tltOIlOtl 011 of the
Zeehan oreuromMost of these comdltlerntlons have not proshy
i1ided satisfactory tnformation for rensonn which are disshy
cussed below
Clork (1959 1960) reportefi that experimentnl wartmiddot in
the Pe - As - S sY~item nas shown that ihe maximum tempernture
for atabflity of theuro tlsseJ1iblrig(~ araenop~trifje-pyrite is
491deg 12deg0 Above thistemperature pyrrhotite to produced
according to tho roao1don arfH~l1olVXtte + pyri te pTrrhottte
+ liquid The assemblage arsenopyFi te - pyrt ta hs o(en I
obeorvea in ~i9jnlgtles froI~ several of the rrdnes represented
in T~ll)lc~ 13 and Firrure 4- t viz Ciiflfltock Sylltes ter
13rUlt-lfll1ia Sprfly Oonfth StoIffi8ltlowll and Zeehull Bell rrdneB
Com~-r4l1 ~middothn t)er~tlTe ~IVmiddotI b-_ (1-1 middot~ljt-l th P~ L I -~1 C~ 0-_ ~rl lt )Y c_4 bull l~ bull
r)oS$1hlt~ teJlIporalure rflng(~i in Table 13 forthi1 pyriteshy
tltmiddotr)imiddotc~lmiddotetmiddott~ al middotmiddotCI ~r~middotdJ nn utmiddot li-i~t of~14Q 1deg t 20 CJ ~ 1d1~ rnbJgtl70ltJ C1io J)~C t Ju middote lC~oSr Jd bull
be pomdhle for i~ill oxcept the Comitock and Dylvester orHs
for Nhleh there i a tJeriolu-i confltct The pyrt te-sptnJerlte
)l~Lrbl 1011 J ~H~ lCgtDmiddott OJ Iole tmiddotmiddot-rA- I llg rf c(oOo(~ v ~ raquo~ _ ~ampJ ~ - fmiddot tl r~ -r tV ij 7 ~bull - ~l lt J C-~ i~~~ v -i Ol ) v JT )
- 660degC foy Ihe Comstocki5ne aphrJ1 cri tie (19 1 mo e percent
l ~) 11 n tctIgtQ1ur 0(1 ~ollQtol v 62CoC p()r Hllrot-i t t~t4 ( YVikJrlt bull4 V ~ ~ ~t 1l)~Io ~~ t__ Cl eJ l J v
jl1middot11middot1-e (QC h mOl e lgt bull)SyJveJter Mine o -letI ~ lirJmiddotmiddot t v ~ Ai J V ~~ C ~ d 11- b - iJ) bull There ~ ~
J$ no te~-(turnl evJdenae of lmrtabl1 i ty in tlHHH~ BNJElrwl)yriteshy
PyrltG 3HserribJages (eg no reflation )iEJS of psrrhotlte were
O h~~a) Jlccrlin ~o -ll nvt i omiddotrl middotrtrmiddot) re1middotmiddottl~0f1 0 ui1l rIL y eurohl El ~ 1 1 Cl tl I c j to ~~ tf4 t pound ~J- tJ JI~~ J
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
25tl bull
the textllral relationships between the minerals arsenoshy
pyri te and pyrite formed approXima~ely contemporaneou~dyt
gtVtth sph~lert to be1ng later in the paragenetic seuence
llhe reasons for the confl1c t between the temperature
data provided byt~he Fe-Zn-S and Fe - AtJmiddot - 3 systems are
not clear The experirnentnl work of ClJrllt (Oilei t) showecl
that increfJsod corfining prefHmre resulted in onlY a
relnMvely sniall riso tn the upper temcerature of stability
of the arsenopyri te - pyri te assemblnqe The effect of
other elementstBuch as cobalt njclfelhismuth or antimony
haa not been inv8atigated and could posibly provide a
partial explanation for theuro Hfference in the temperatures
I~~
The eXIalytical unctlta1nty 1n the iron anaJyaes of the
Zeehan si1~n~lerite samples may aecount for at least ) part of
the observed difference to middottem~erntures_ If allowance is
c 1-) (A 0~-304 in t~llt~II- lec~ro-o~to t-hltmiddot cqtti un)rt- 1)1middot nmiddottymiddot v 11JJ Ilt-~~f WiI ~ -
----- (~hen possible temperatureprobe Inicro-analJses the minimum
for the Comatoek spha1erite is 480degC for B vrilue of 14-4
nola cereent FeSBut in view of the ClOtHl agreement btween
the lectron- L robe result and the uni t-0011 meaurerrunt
(see Table 12) it is unlikely that the t~le iron content is
as low flath s
It is alBo pos ible thot the Conflj c t of tepiera ura
finta is pflrtly explained by the observation of Toulm111 an 1
Barton (1964 p668 )lhat the JleS - ZnS solvus curve may be
in error 8110 in nee i of furthlr ca1lbratj on
Attempts have bean made by some Wor~n3rs to use nunmixing
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
259
temperRtU1eS of solid ~lOlutims to set Imver I1mi ts f~o the
temperatures 01 forma1t1on of the miner~l aGsemblsgos conshy
cerned The assemblage s1haleri te-chalcopyri te hiS often
been used ion +IH~l~e estirn~3tes of mirlimum temperrltures of
formation~ Buer0eImiddot (1934)corrled OUt henting experlmrmts
wjth samples of sph[lerite from Binghnffi CanyonUtah and
reported that the temperature of ullmixing of chaleopyrlte
from the sphaJ art Ia for these samples W~lt~3 in thf rmge
3500 400deg0 The presence of egtrsOltltion bol1es of chalcoshy
pyrite in sphelerite is sometimes used to ill(H0n~Ge that the
aphalerite was depoa1ted nt tl ternperlule of at lea8t 350oC
(eg ~c~Wt1rdBf1954)
lilthvards (1954) t Lyon (1959) and J~dwardG andL~lon (1957)
have repormiddotted on heatin~g expcriments rm ore frof Pine V~le
Queensland and the Aberfoyle Pldne Hossarden 1nsIDenla In
---shythe experimfmts on the ore from Plne Vide w1ere ehJlcoshy
pyrite horni te tmd temiddottTnhedrimiddotte occur in or5ented elIsolution
interfsrowtfUl sarnpl Em ofthc ore were homogenized hy heating
for nhoIJt tOO houTs at 4[-50 - -QOOC F(~war(lr-j) wd IJyon fountl
-that the orLin~l 1~j~el1Ilr textlrm~ could be reproduced
only bycoolinl tmiddothe homog0n-izefl ore rflpidly If slower
cooling was ~llowed t an eTu1rrfll)lar mosaIc of cf-lcopyri te
0(1 tetrtili1euro1rl ~e resulted The ori~~inaltextureB were obshy
tiairHpoundJd oo1s by quenchi ng fIom 4nOOC to helow 250degC and
Iidwljrdr~ and lyon concluded middotthat the m1nernlizing flvi(1S
were intrDdu(~ed at a tElmlEzrature of at le~H3t500oC and cooled
to about 250degC in ~~ matter of minutes SimlJal h08ting
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
260
experiments were performf-)o by lOvJ~ rdH and 1von (1957) on
ore front the AbEIIfoyle Mine Thi s ore contains exsolut1on
intergro 118 ofchlcopyri -te st~1mli te and t~phaler1te and
the reaul ts of heat~ing expfriments were interpreted as
inn I catingth~it thlt~3e st~lphjdes w~ire dapord te(l at a tempershy
atuce of ~lbout 500degC and cooled raptdly to less than 400deg0
Accordine to T~dw~rhl and rlyon tihlrl rapld chilling caused
t1e unmfxine of the uolid solutions to be arrested
T10 cooelnstorlS of ~dV111r(la nd Lyon for the Pi neV91e
rmd f~b8rfoyle ore h~3ve recently been 1isi~t1ted by Brett( 1964
who has carried oui extel1fd le con Irolled cooling eXIHrtrll0nts
lton solld solutions in th~ Flystem Cu - Fe v Brett has
(lelllOnfJtrated in middotthene expoI1mente th~qmiddott ex-solution lameJlae
ean fornl t1 31014 (3S well Ha by repin cooling Accordtnp to
Brelt cXe sllould bE~ taken jn~he interpretiation of tempshy
eratures of forro1ti on of minerll a~3semblng8 on he hmiddotsis of
rcbomog0nizetion exporimenfs Brett (p1268) states that
nconsi1tuinH the di fficultiea in in terrret~ttlon of results t
the only gt)o~hermometric information trt3t cBneefmlt from
such rehomogenizetion experiments iB n minirflUnl ten1perature
)f middotrArlll~middot middotlon qlmiddottnmiddotlmiddot~middotd bmiddot 11~1lO(ferdrlnQ 1~lrrgt11 jmiddotmiddotl-h-middot~ ttmiddot J ~middotlbullbullmiddot _ 01gt Av lJ 1)1 j) _~~ _ ~~~ ~Jr lo f IV A V~i it
stnrJe grlli ris It
The cnlV rdrwrFll rtssemblHcsa present 1n the Zeeht=ill ores
-1 nbull ~ J t oni Y - _onelt h f lch lmiixtng tempshygtQ eYbOl 1 tlC 13 bull or
erflture ddte exist 8r(~~ the a)SHIHnblages chmiddot-lcopSr1 Ie- sphalshy
eli te anti ch lcopyri te - stfwni te The foruler j El [1 wideshy
fJpr~vld BaH1tmblr~ge and the Ifltter occurs n I the OOflfih Wane
--------
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
261
and inthe nearby Clarkes Lode of the Zeehan ~JueenMine
As mentl once] ltJbove Buer~Gr (1934) reported the unmixing
terrturmiddote 11 Clj 1 purmiddot 1- f middot1 pmiddothmiddot~-l p + 8 310 lOCeblJJlI Amiddot IJ~ ~Pt tl lJt~~ ~ lti iI (1 L ~~J ~ lJ~ c tT~~)
AeaoIUng to Ndwrds (1954) the unmixing tfHnptHdture of
chBlcopyri te from stannite is 500deg0 These flgures eoulcl
represent minimum temfu-fitures of fonnqtJ on for the HElSernshy
bhtges conc=rned t am1 as such they woul(l not conflict with
ths tern pcratur~Hr3 obt ined from the pyri te-Bpnmiddot leri te UfHHunshy
hIn 0 ri-- t n v-l r omiddotp the ~ ~ ri nt-i-ll middotNO middotK of ~rot~middot (0~ (~ G 1- bull l 0t c 1 ~ ~ ~I 1-0 lj~middotC C 1 f -l~ t~_ tJ i t bull
eft) it would be unwise to attempt to pIece restrictive
lirr1 tiS on the pyrite - sphaleri to tempernture dnta by use
of lhese unixinEr tem erFtures
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
262
Gonc~lusions concerning temperat~ures of formatlone
It is appar~Hlt trvlt there is no suitalile freologjcGd
thermometer to enable dcterlination oftemperrrtures of
fOTroation of th(~ 2eehltM~ oreo llthou~h amlyses of the
nplolerl te hve sholm nJgniftcont variations in 1he iron
ennent temp(ratuXes inrli ~a ed by the pyri te-Dpholeri te
nsllemblfgej are no t of any quantt trtti ve use in estlblishing
terl)ertture trends
The (mly oth~~r BulJltde afjsemblH~e to provjdeluH~ful
tnform8-ti on on thf teJiferatureu of forrrntion is the ar~1EnO-
IJyri te-fyri te af~sembl~gemiddot Tide mincrJtll pair places Hl)
U (T l-imi- or Omiddoto iwtel-y 1)middotOOoCmiddot qv t-11~ trfleVmiddotmiddotl+IUImiddotmiddot~ o-Ptt- U fmiddotJtJlmiddotmiddotJmiddot- middotmiddotmiddotmiddotIbullbull ~-I ~J bull L lIlIi i4J1-IV ~
fOTTrll tl Ofl of rnony omiddotf the ore-bo(ij ~~s in tih Zeehal1 Ft (dd
I_JL h1~ worr oflvlmiddot~lomiddot1 ntlV~ -tJ nndJ J~lrrne~1~1_~( (9J7)r J ~)0ltbullUl ~~l--t ~ o~ ~r1
Barton (1961) and iWarkham (1963) h (on~)idered whu in j(~r-
Iretj_nt~rH condjtj118 und er which theH~ oroe were forrnerl
it j1 possible to mrAhr) le fol1owtng BUH~~l~]tions concoxuing
the OrE~[l-
1 Sphnlerite in h i wee ternpart of the Zeehall area--
formed at tempt1ratures in the ficin ty of 5COoC
and r)t moderate snllptmr vapour ])resfure
2 rh~1f1 eCrHHH~ in trOll content oftheflphaleri tE~
frof tEwt to enst was eotltrolJed by Pt oec1lne in
hoth ternol8talre of fOrmtition Rad sulphur ictiVit~f
3 ThE deponj ts in tlHJ Zeehanfi elc1 were formed from
801) tier wdch move1 eHltvvardrJ froJthe grani t1o
body
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
263
It should he emphnsized that this interpretation a1shy
though ltJonsidered to be geolGrtcaJly and chemically r(lfH~jOnshy
able must be reg1rdec1 as -tentatlve liurlh8r exrerirnentnl
informte1ition reg3roilJghe var~l DUS mineral 1u1solTbltges is
rcepdred befoee a more smiddot~ttsfaetor~middot intf]rpretat on 1 a pO9Sshy
1ble ]IJrther knowlt~dge of the f[~nla1inite-tetrahedrite
d 1 lEWctoition curve could be prirttcularly useful Sjms and
f)arton (1961) were ~lble middotto use the enargite-tctltlsntite
rel)tiorlshtp succeGsfully and it ts possible thlt a similar
treatroent of the correspondj ne famatifli te-tetrrlhedJite
relationshj p Would amiddots1st in a better approximation of the
temperfltures amI aetivi ty of sulphtU duri ng forrntt5on of
the ZeehtUl ores Barton and Toulmin (1964) havlt~ reported
that preliminarj work on the v8r1etton of the fugac1ty of
the su-lphur with ternperatiures for 1112 SYLitem tetrHhedrl teshy
faIlatinite by rne~1ns of the electrum-middottar~nlsh method has
yielded pr(jmisin~ Yesults The relotloflshis have not yet
beurolenpublit3hed as Ba-Mon and 1oulmtn considered that further
inve3tigation was re llired before pub15 catmiddot] on
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
264
~3lnJPHUR ISOreO ~E COvPOnTION bull r
Intrmluction
In recenl~ yenrs the applications of isotope f31uclies tn
orf~ genesis have received cons] cl arable attention In pGrtshy
icular sulphur isotope~1 nBYe been widely used as a tnol in
the investigatlon of the origin of many sulphide Iliineral
deposj ta and in ~H~veral CUJHS sulihur isoto1 G studies have
proved ulsful ln differentiating between opposing tl1eoriss
cm the origln Qf the cl aposi t8 cOl1cerned
ProfeSf1Or M L JenBem of Yale Ufdversity has kindly
C-Urie1 OUt analyst~s of the sulphur iaotopje composi tiOL of
sevoral lHfTplefJ or ore fr011ihc Zeehan districi
BefcnethE 1681)1t8 of these analyses aTe (lic~eusset1t a
brief sUTnJllnry of 1he bnaic prj ncipl~1s of Julphur lnotoL e
etufHen is prosenter1 bull
The j~~otopes of interest in the study of ore Cl tJposi t6
534nre 532 and t since the~H~ are the most abUYli1ant iaotopes
of sul~hur Variations in the relative almndanceB of these
two isotopes can be dil30ussed jn terms of 332534 ratio
values t or in terms of S834 per mil ([D) valltes The SS34
vnlnee represent variations frOlH a standard v81ue occording
to the followiD~ relationship_
SS34(5o) = lts34Ls32~ sample - (S34LS32 standercJX 103
(S34S32 ) stawlard
Tle stanchrd used in almost all sulphur tsotope ~3tUd1es
is troilite from the Cnyol1 Diablo meteori ta witl1 a ratio
vt~lue of 332
534 22220 9nd bS34 OOO~lbD (Ault and Jensen11 OIl
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
265
1962) 1~he value of bS34 000019 c1J130 genercJ11y 9Jcepted
t)tS representlng the average compos) tion of terJCGtrii1J
1 1 (I~C onm middotyiIl Th~d 1950)LJ~l bull xt 4 VA f ltl ~w ~tc ~ilmiddot ~~ -C ~ 11 - v t bull
The obfHuVed variationpound tn relative l)roportiono of 332
and 334 in various sourees in nature are 6 1017n in Figure 7
The most useful crj terta in Bulprur isotope stuc1ies of
IntlH(ral dep)sits are (a) the total s~read of SS34 values
shovn bythe sulphide minerrla i11(1 gtven rlep stt of Airotlll
of reInted de[JOBi ts t and (b) the difference between these
bS34 values and the ~terJm-1trial average of S334 010l
If the suliicide mlnertd(j from H deposi t exhibit a
narrow rJrlge of bS34 values witb an average close to
SS34 fI O)~o this is norm~111y regarded as good evidence of a
magma-ttc hy~lr)theXmal orjgin for the deposit1e the deposit
is regar(led amps having been deposj tef from hydrott--ermal
oolutions of magmatic origin (Jellsen 1959) Such an origin
would irnrolve a homogeneous source of suljhur and avail-
able evidence sugE~smiddotta that the processes lauUng up to the
formetion of theCle or-eB (to nomiddott crruse Bignifican-t frnctionshy
ation of sulphur isotoI)ea brtlr(~en t~iO sUlphide mi-nerals
(Ault anet [ulp 1(60) bull
bull
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
Sulphur of H~drothermal origin
Sulphates from Evaporite Deposits
Sulphates from Volcanoes amp Hotsprings
-r- Sulphates from Sea Water
Sulphides from Meteoritesr I I I
r- Sulphides from Mafic Igneous Rocks
Sulphides from Acid Igneous Rocks
Hydrogen sulphide of Volcanic Origin
Sulphur dioxide of Volcanic Origin Native sulphur of Volcanic Origin
Native sulphur of Biogenic Origin
Hydrogen sulphide of Biogenic Origin
I t
A = Average Value
Sedimentary sulphides
Sulphide of Hydrothermal Origin I
I
bull
2100 bull bull
20 bull bull
40 I bull
60 f I
80 I I bull I bull I
2200 20 40 SHS1tshy
bull I
60 bull I
gO bull bull I I
2300~
I
40
FIGURE 7 Sulphur isotope variations in nature Compiled by Tupper (1960)
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
~O
A brol~td 9ire~d of 5334 vn]1)eS jiB often indicntive of
a biogenic origin withthe sulphides having been deposi ted
as the re~3ult of reduction of iloluble sulphate~ to insal
ubIe sulphides by the action oe sulp1~a1e - reduc~l ng brileteria
11 ~ ) - cmiddot ntmiddot 1 wor b v ) lr- Cl ( 1Illt - ill 1 fOIlI l~ erlJIHI j de er ~ ft~ 1) ~ 1gt fS J lt0 Cl e bull lt
1951 JoneB et cI 1956 FJely ax~d Kulp 1957 Harriaon
and Thode 1958) has demol1stre teuroHl that frct1onaticm of the
aulphPT tsotopes takes l11ace luring relvction o~r 8ulphwG9s
b -the bac tfri6deg)1 llovihrio dfs)l~)hulj c~nC lJnrin 7 f-h1 SiJ - - - ) ~ - pJ4 ~ ampd bull bull- ~ middotmiddotmiddotmiddotfgt U ~ bulllt
relf1ucmiddottjon which involves a changf tn vnlrmce of sulphur
from + 6 to - 2 the lighter ipoundwtope (832 ) is cOf1cent1tecl
In -the snlphilje phase leaving th~~ sulpha te enriched in 334 bull
The literaure on su1IJ)ur isotopes is eift(Hlt~ive and
for cornprehensjve accounts of the causes of fract1 rmat5 on
of sulphur isotopes r1f1fi thfl1nterpx-etntion of SVlIHlr 160shy
topic compos) tion of mi WJril depord t8 the rElul] er is r(~ferred
to Jensen (19591962) Ault (1959) AiJlt 9nd (vIp (1960)
an2 Stanton (1960)
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
268
l~esults
Of the fourteen aampleli analy~~el for the rilthor by
Professor Jensen twelve were selected from mines in the
Zeehan field imd two from mines in nearby rillf~ted are~1s
One of these two eamplE1fJ wriscollected from Sveneyt s Mine
within the Heemskirk GrI1nimiddotte and the other from ti1ayne t g
tUne which ia sttuctted south-west of the Zeehan field nnd
is fa sJ10rt dhtanee south of the nouthorn mirgin of the
rIeerldkirk GI13Jlite T11e twelve samples fron the Zee11an f1eHI
were _H~lected to provide Et resonable geographic coveroge
of the field t and 01pound10 to povifle analyses of the sulphur
isotores tn saveral diffRrent rmlphiCle minerals
The rStmlts or thenalYHes are ahown in Tn1)le 14 )ml
Ire presented diagrlmrlf~tic11y In Figure 8
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
2051
miTT~ 1i JfbullttLI$
Sulphur inotopJc composition of
I_ttls tfIIJ MO middot 1
SMple No fill t bull
r21J9A J
5 541vF +~r
X2587
I ~A 4011
X5251
it5236
X5198
K5205
X5210
x52in
X226
Xmiddot252
X3162
X 5283
11I 11
n r- iIl HI
rl1ine -COI113tock
TeLE
SW8lU31 ea
Oonah
S~rDmiddotUmiddot middotr
I~t)rl trlnt~t S L
Occane
Z~ehanBell
Silver King
No2 ArgGnt
Btormf3i~1 own
Grubba
I1itlyne t IS
Slvee11cy f S
lt Ili~ PIal lP
ore minernln
_ c i 11I11
Ttineral
Sphalert 1~
It
St-1tnnite
Boulnngerite
Gnlene
n
Pyrite
Gl1tlena
n
Prrite
Galna
Iyrite
Sphtllerite
Zeehan
S$34(0)-
+69
-07
+65
+15
+4 9
-36
+12
+17
+22
+15
+13
+71
+58
+151
I IloU $
IeotoIHl euroJlccljses hyML Jonsen Yale Unilersl1y
t TnsEJanianNluaaum aceeseion numbers
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
170
I) I) LV o
Vontana S L (gn)
I J1
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
211 bull
ierEretrttiqp bullof re~J1ts
The fUlalji2len do not show any correl~1tton betweert
sulphnr isotopic oontent 8nd minernJ species nor is there
any al)~arent relaiiouship with tbe host roclm for the mines
concernc(l SimllRrly theee in no conaIftent reJat 1onuhlp
as fH as C1rl bo juclgod Nith probable terneIatucspoundJ of
formAtion The analyses wi~h SS34 values of the or~ter of
-+ 50 or greater represent mines locate(l in the fe)1en
Flucl 1l0uth-western part of the nrea bllt thi~ is not fit conshy
sistezlt feature since the lLE t1tlIH1 (b334 -070) is
also located in this region
rhe total sprend of bS34 vlt11ues for the SamIl(w is
36 to + 1~i1iof with an average value of + 310 Thta
range i~ crmsidElrlbly gre~lter then would be expectHr1 for
G~~pomiddots~ tltgt of lJ~~tO---l~t~7poundltl +1middotto hT(tcmiddotmiddottmiddot~erIl1 A Jfl ~ orio1rt 1 CO-)~jgt r r1nlt-Cl n Vf --11I-~j- ~ ilJ ltbullr $ H ~ ol li ~ v7J 1 tl-l
the ldels discussed by Jenen (1959)
If thl ina-lysis for 3w(~eneys liLine 1 8 excluded the
range be(H)IDIJS - 36 to + 7 11Go for whIch th~ average is
+ 28 Tlda range is etll1 sor~e1fImt greater tmiddothll Nou1d be
expected for depo13i1gt13 iornM~i1 by sulphur derived from a homoshy
geneoUf~ Bource as rEFiulrerl for 11 m~grfJatic hyctro Lheurormal
origin Deposits formed by such a proeens are not eurolXljf~eted
h +il T r tmiddot hmiddot bull T i t ] lttr 5~1 f +0 ~ ow vmiddot~rlf l ons bre~tnmiddot n apli_oX rna lt ~ 10 XO ~1e
acro value
Nkany of the Zeehc1U nnalyE1ee are well wi tlll n thE) rlSmge
of OOO 5)1( rInO it 11J sugrnsted that~he OJ(H1 represented
by ihEHH~~ analyr3es were forrrH3~ by norm~ll ffiagmatic hydrothermal
---- _--shy
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
272
processes wi th the sulphur haviIlg been der1ved from a homoshy
ge~JUs 80lxrce fluch as the vppar mantle byaelective volashy
1ilzation The analYfH~H QutHide this nlnge are enllcfled in
s34 wiich strongly EIlitggests contamination by a source rich
in suJphate
rhe sulphur tsotope fHulyt~es can therefore bG inter-
prated as indicating that tlHj sulphur in tlH~ge OrEH71 W~lS
tierlved from two f10UrC8a Ifhia is so the rnos likely
e~phUlati(H) VCHlld be tltJlt Hed imuotsJ eontainini eedlmentnry
sUlphate were nssimilated by the magma durinn emplacement
of the Heemskirk Graui te andlhat the sulphote was rerluced
to sulphide during the aS81mila tion proeem~
rhs dat~ of fudge tll1d lhode (1950) and Sa-kai (197) bJ18
damonatrHted t118i l~eductS()n of sulphote to sulphtd0 at
ter1peraiures in e1t(~epoundH3 of OltPC will cause very Iit1le fl$Cshy
middoth ~-middottImiddot 3(po 19t7)t middotlmiddot middott1middoton of bull~lQ smiddotl]middotmiddothlrA --eT l) l4middot ~V1G-~I P-lr~lJl ~ 1- Ui tpoundol(Jw(~ini f I bull V(IQmiddotmiddot ~j
il1u3tratentha deere~1se in the fra~ttonation factor wi th
inoretlE~lng temperaure
AecorfJing to the above hypotheais the 8ulcbur of mag-
matte QTtg1n would have becorne contsroJnated by auJphur from
a sul1111atu-rich s01lrce giving I-hle to th~ obHerved v~lriilt-
t bull (34 1shy~OnB 1nd~ va uss
There ore h01Nev~~r ~~1middotlermt1v) interprfYiations which
et)uld be rn~i(le for the ~nalY~Hs Tt could for exarrrple be
flrgued thfJt thes -lualyses lndieate middotthat the ores in the
Zeehan field are unrell1e~l to the Heemskirl( Grani tat in
vi(~w of the analYHi~) of + 15 10 from Sweeney 8 lVline cortpared
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
213middot
1080H 0 + C)
CO 1060IX
s 0 r- + 1040 CI1 s 0
-r-l + C)
1020 CI1 H ~~~
1000 0 500 1000
Temperature (GC)
lmiddot~fmiddotltlflmiddott 2 JL bull Variation of frgcttonation factor wi t 11 tempshy
erature for =S04-= (Ilrom Sakal 1957)
with 710 aB the high t3lirtbS34 value from middotthe Zeohan field
Another ~tlterlativa iilerpretation would be t~hat most of the
orea inthC wertern anrl l21outh-western part of the Zmhan
ftcl(l are relatampdto the Heemskirk GrllHli te whereas those in
1TH eaBtern part ofth) field sne related to some O--tH~J 30urce
Irhe firs t ()f dlese interpretati 011S is nr)t favoured by
the author he(nune severaJ eaJIiples sholtJ an enrichm0mt il1 834
by more than 5f1Qa- This HuggEstBthat theee ores contain some
E1ulphur derived as explmiddotined above frorJ el ~3nlphnte-rich
fJOUtce
It is not possible to conclus1velr reject trw second
al tEnnamiddottlv(~ bUt i t~ is conrddered to be lese liely tihrm
the hypothesi ovtlinet1 ahove One factor not in favour of
two oomrletely ~epgretie sources for -the ore dpoei ts ir1 the
mlm)rC10l~ical zoning of L11c ore~1 11 middottl~1 resp-ct to the
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
274
Heemskirk Grani tat as described in la subsecuent section
~~he systematic pattern s~tOwn in the iron conttmts of the
Bphalerite (as Riscussed in the previous section) also
sUfgests a relat1onshi IJ wi th the grnite body
Inflepend Emi eviclence which asr~ll sts In middot1he in1erpretashy
tio1 of middotthe origin of the sulphur it provided b~r recent
work of membltius a-f th$J)epsrtment of Geophysics Austr-11ian
Natiorull Unlversily 11118 work has been concerned w1Ch the
compos)i tion 8nd orLin ()f the TIeemskirk Granite tind will
be outltnaf~ in t~o forthcoming papers l)y Brooks anCl Compshy
StQ11 (in preBs) and Heter arid Brooks (in I) e) Q ) Thebulli~i ~
inves jgation~ of the grant te have tnvolved fiel(l mapping I
petrolng1cal stud i es t ~nd measureW(H1ts of the Rh Sr Th
and lJ eOInposi ttonm Mr C Brooks ht)s infoI1ne1 thts author
t t11~ d-t ll~nltO lif ~)~( middottgtroQ orrITtJ ) haII~middot
l - t cotObint JJit f j tiio 1)lJ J ~-Lo-t~1J1-middot 1 -~ 1 ~
strongly suggest middotthmttwo period CJ of Glctlvi ty were involved
in the forrrJatlon of thr- grrmite According to the theories
prOpCiHj(l by the above authors t~he ftrst phase of the mtlrna
was accomianied by i n-carpe Trol tiOll of Precftmbrian sedtmen$o
bUt the second pJiase was a more nOrJTI1 magmattc i n-trlWiOfl
lit th far less accomptluyfng Volr-diilea trnlr3 the fie~Jt ph3se
and difl not trlvolve significant assimtlatlon of crlu3tal
rtt9t ert le1
Th1s trleory for tllc orLgin of Lh grful1te UU1HS is eomshy
patiblevdth the fFllp11ur isotope data grlfd proljJ~es a
mechanimn for lhe dcrivation of sulphur from two sourees
If th1stbeory Lo correct then it irvH cJtes thnt the ores
--___-_~
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
Ip)
of the Zechan middotfiold are genetically reJttted to the fiest
phase of thc gran te maryua
Another flpproach whjch provide8 some further evidence
on the or1gin of the sulphur i~J the selenium content of 1he
sulphides rr~hj e if discussed Jn the following section
A dlSCl15SiOll of~h8 sulphur laotopio compoBi tier of
the Zeehan ores lOuld not be complmiddot)te witwut DOInc roferenae
to isf)topic ~)nalYgeH of other ores from the west eoflS~
~iooil Iii n montl1middot~-gtO~~~lmiddotLl_ ft SolJmon omiddot lJ-l~~ Umiddotr 4middot11 w _ o~Jmiddotr1middotl1
Tyen3Sm8uia h8J1 kiniHy s1pplj ad the author w1ih unrmblished
stJlptnJr isotope anrtlyses of ores Iromthc Niount I~yel~
Henj~son Bell and Hosebery depofdts these ~XlHly)as were
c~ried out by Professor J ensen and ranges ofSS34values
tlnd thl~ resp~ct1 va averag(J1 values are i3hown in lIable 1~
The r~Hlge aOJl average of the Zeehnn ftnallses are included
for comparlsorh
W1d le lt ts not posf31ble to discuss thEHe results in
ae-fttil wl thout goinlz~ well beyond the scope of this thes1s f
it is nevertheless interesting to 110te ttat there Is an
aplaremt middottondency for all sulphide deposits in western
Ot_ 4- ~t1 I)r ~if_~ 1l 1~ ta J g 11
1middot jt u IH~ricre+~_J of ~34 1t~ ~s ()lt~rtmiddotjlnrnLrtotJ mntmiddotCAr to hOlrJ Cl uk1 ~l U Ti~ vnf0_ lCC llitr l~~jI lL bull ~amp _
interest in view of the posnihility that more thon one type
of or-tgin ili representel bytH~aG deposita lirberefH3 the
Ren1~)on Bell easel terite-p~1rrh()titc 01(~a are aceepted amiddots
magnlCttie hydrothermal tht orlgins of middotthe M~)tlnt Lyell copper
ores and the Hoaebfry gaJcna-sphaerl te OlefJ fare lot clear
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
- -
7r2 )
ThBLJl r 8 bull 1_ 15
Summary of sulp1lllr isotopi c composi tion of orCfS from
western T~lrsant8
It amp bullbull 1 ~4il
Localitjr V1ineraJs Range )fbS34 No of Avelage
anafolBEl(1_ vaJtes(o) fmalyseB ~s34~7fol
bull I if RI bull bull
Mount Pyrite - 28 to 18 46
Lyell Sp11Etleri ta + 86
ehalcopyrlte
bornlte
Henison Psrrhotlte + 22 to 10 +- 63
Bell pyrltegEtlewa + 81
rh n 1rl middot1middot ROldebery U fUC~~ Wi BU + 92 to 11 +11 7
cha1aotyri te 138
gfiilen9 pyri te
Zeehan- See rable 14 - 3 6 to 14 37
Heemsk1rk +151
_ill 1_ _ _ pr
R(middot middot 111middot] 11 middottormiddotlC l~F 111 ~~ CtolIDon (Utl-t~middoterSlmiddot tT nf t lt-wll t Lt 0 U C)rmiddotmiddot ld vd JJ bull d~J v - _ ~t If 1 c iiIJ iJ
ffir l ) rlVrtT ~~~j1~ ~middotlttul r C~ J Dr N L Markhmn (Untversi ti of Net South
Wlctlee)suggest- tiled these orepound~ may 021 1lt lerwmiddott in j()It
rel~=iier~ to CGmbrhln voloanic activity (Solmnoll 1964- Soloshy
m011111(1 Elms 1965 Nlarkham pRrEh comm)
Purther work is near1ad to explain th~ appurently conshy24
lidstent enrtchroent in SJ in th( ores i11 western Tnsmnnia
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
271
S U L P R U R S Y L R N I U M RAT I 0 3 WMe=cI _bullbull bullbullbull1109 P -t lIP t
filWJJ t S n il rbullbull ~ (1qr4) r inUAg ~-utj+l middottmiddot1~~(i-t 0 WHo(~J~]C)- J to J tJ vmiddot~ ln~lc~ bullbull ) ~k _ ~-l ~~~ J
eonienmiddott of ores from many mineral provi-nces tnllstralili
rmf included in their results amplIe fnn nnalyBsa fromthe
Zeehan and Heemsldrk areas It is of itrtf~reBt to brh~fly
review some aspects ofthEr work t)f Edward~t Ul0 GnrloJ1 )nd
to r11scuss the nelenium (H)1tjen t of the Zeehan oretj Hinc~e
the S3e ratios offer a poastble correlation with the
eul Intr i eotol)E~ flnallSefiJ
IrhG p1Jrr18r-j objective of the Mork by Edwcrds and Cirlos
waa to test 1he use of S Se ratj os as a method for d18shy
+- gtpound1 -lng 011111 1 0 mimiddot 11 ap -I middotc of h1y-l r tho 11 lA6) I Q ~l s d v 11 Umiddot tgt bull os 3 111 0 gtrma
origin froE those of i~e(Hmentary origtn Golr1achmidt and
Strock (1935) had -ound tlwt pyri to of 8edirrHntary origin
had SSe ralos of hc order of 200OCO or more wl1ile
pyrjtt of h~ldIothermal origin had Cl SSn ratio of 10000
to 20000
lrl I ct-ilt ~n(t middot+rmiddotAM1 ( 93E)~) 1 Gi)ll Imiddot~t+ 10t8)Av ~ U If l t~ I 1) u -w h (ii-J~ 1 i- rL$~jtU J 1 J
have expldned th t lhc low selenium cC1tent of sefltmentary
pyrite is middothte to the breakdown tn thep~rtnerf21hip between ~
sulphur and selenium i~uring the weatharing avele the
selenium content of ~1eurot) Vdeter is very low since rnost of
tho delentum 18 prEie1L1l tated wi L~~ bottom oediFHinGs iiiineralf1
11 h lt rr lt1 1 -ln~ 14 to e i n 41gtVlt) i1 1 ~ (~C - bull t C ffltq1middot n~~) llt _ ~J ~JriJ~ il ~1iJ 11 I u1 1~i ltto _ ~l U t-i- l U ri ~Igt igt~ ~JJ I tr Ill bull
very It t-tle )elenium
l~lward~j and eHrloe (opmiddot clt) measured the sulphur and
selenium cOl1tento PUllf calculated he SSe r(ilins of
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
27r~ ~~
BulphJde minerals from vsriOuf1 Australian min~ral depordts
As a Ieuro1l3ul of thai-r investigations~ Edvvards i1wl Carlot
eoueluc1ed thJi [it high selenium content with a SSe ratl0
of middottiheocder of 10000 is positive evidence of hydrothermal
origin A low selenium content givlng high SSe rRtios
was cOlsidered byFiwards and CarIos tabe indicative of
3cd5mentllry origin but accordlng to EchvardpoundJ and CarIos
h-snroothermal sulphide depcl si1iS could be low in selenium
content if formed in I~ aelenimn-lJoor province_ Tbe resuJts
of Williams ana Byers (1934) are in essential agreement wlth
these conclusions_
It should be no1a~d that the pyrimiddotte depostta at Nairne
Soulih Austiralia were found to have SSe rtJtios raneing from
9910 to 13400 for pyrite sampes ltUld from 20600 middotto 37400
for samples of pyrl-le-pyrrhoti te concentrate On the hasis
of these resulusEdwaras and CarIos concluded thmiddott the Nairne
depoai ts are of hyclrotherrnal origin hut it is generally
C011sidered that 1ihese depoeito are of sGctimentary origin
(Skinner 1958 MirafllS 1965)
T119 four analyses reported by Ec1warda an~ Carlo for
the Zeehan - Heemekirk region tre listed in Table 16 T~ree
of the ~ulalyses represent sulphide min(~rahJ from mines in
the Zechan field and the ~ourth refers tio a earrple of plri to
from the Heemskirk Granite
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
lt I t
TABLE 16 11 bull Oil IllJIl bull
Sulphur rind seleni urD con ent of orcm1nerals
Zeehan and Heernskirk (J~dwards and Carlos 1954)
Mineral Locali ty bull11I
S(~l Se~0~ SSe
Sphalerite Swansea Mlne 2977 0000 59940
Stanntte Oonah M1ne 2776 00019 14600
Bot-dangerite Spray Mi ne 1782 aooee 22275
Pyrite Heemski rl Grant te
(precise locality
not stated) 3175 -The S Se ratiogt3 of tJw 13tannite from Oonah Yii ne and
bo~18n~erite ~rom Spray Mine are compatible w1t~ the
eXpected values for ltyc1rothermal ores but the ratio for
spheJert te from ~)wanse8 Mine iE not conclu13i VB The sel shy
enium con tent of the pyrite srlmple from the Heemskirk
Grani te was below the level of detection for the me t1lOd emshy
ployef by 8hvard8-wd CarIos bull This ~Fmple V8S relcrtc 1i to
COl1t3iBt of Ita number of loose cubes of prri te encrusfed with
minute cryJ tale of cosai tcrl1e tnd hr~d ~3uch oblJioU8 mag-
matte associ ations th t Edwards and CarIcs concludecl that
the Heemskirk 8_rea represented a selenium-poor provinne
It is int(~re~tin1j to COmpl1re the SSe ratio in Ttlble 16
with ltlw stllphur isotope araltseti in Table 14 Alt~middotough
the number of sampl ea i81 lirited thsYeuro is H cle~1r correlation
between the two sets of data The SSe ratjo of the pyrite
c 34from he HeemskirkGr~Hlite and sthe 0 vC11ue of sphaJerite
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
2~j-0 bull
from Sweeney s ll1i ne t Ni tht n the grani te are both incomshy
patible with the respective expected values for snlphur
of mtlpm~ tic origin
WhereBlS gi~wardn tsnli Cnrlos i ntcrpreted the low neleniwl1
(H1ntent of this pyrite HS indicat1ng an asooe tiimiddoton with 8
selenium-poor province the 5 S34 Vf~lue of the Sphll (~ri -ta
lt ~ r J lt-middottr r] y lt Tn + re th t middot-hmiddotmiddot su1 1 r imiddot t k y rlmiddotmiddot lshy3lt1e vui- gtUbigtegtb~~1 u~ lrO i-1ulJ n 1110 li _ a
iwd the spltalerite hOJ3 been derive(lhirgely frotn seiiifllentary
sulphale byrhn proeese3 oUlline(l in the 1JreVOlls seotion
) b 1 th ( S t gt t St~34 1 ~ ~~f - ~ bull bull - - _ bull c~~ 1 bull _ -1 n H) Ekbullme~ e ) e r~ lu nfJ i) VB ue
of 1he sphHleri t~e from ~iamH~ riline both mggest ~i mixture
of lntlgnatic and sedirflentlry sulphur
l tJ h~n ~1eremiddotfo~~It bull L~ b~ +~1~v 1 Clgt b th~ s~hr- t3 ~ soi~ If J - f-~ 4Q~to)eI J rJ li lt --1 A ~t
analyes and the sulphur - fJelenium analYfHm of ores ta the
Zeehan and Heemskirk 3ceas are ir good agrEH3rtlampnl ~tld provide
supporting evidence for theories on the origin of the
sulpmr int-hEJ aces
11hese results indlcate thnt S8e I[~tt(Hl of ore minerals
may bf~ of p~ore value in s tufliea on the origin of ore deposits
than has b~Em Iireviously acknowledTed However i1e above
results ahw emphsiae thlllt Ci1re is needed in the intershy
pretntion of SSe ratlos It would obvlously be interesting
to hnve both sulpnlr tsotope rmfl eulphur-seleniwn analyses
carried all L for lt1 e(mlprl~hensive rHlo repre8ent~ti ve sui te
of sul~Jdde a~unples from the Heemskirlr Grrmlte Such a
project caull providr further jnformati on of the validity of
thE~ tdeas expresfeJ in this Bnd the previouf~ section
![eprints.utas.edu.au · 2014-11-18 · Dr- Turnbull. there are inge that perp]sex me Am I to Chat the aspceions he makes whieh you do not cont,radiet are ty.ue it that groke before](https://img.pdfslide.us/doc/110x75/5ea5c35e79b2cc3150389bd4/2014-11-18-dr-turnbull-there-are-inge-that-perpsex-me-am-i-to-chat-the-aspceions.jpg)