15 l15

MINERALOGY & PETROGRAPHY QAB 1034

QUTZ 2z5'h ApRIL 2011

5.00-5.3Opm

NAME: ..{.Y.t Farohrn y!:P

ANSWER ALL QUESTIONS

1. To determine the' is used is the:

index of relraction at a rvavelength of 589

Lza'l-.s l\

/ o,-t]1,^* tlvc^i r*h o n rn <fi-c d

I/D: r 3 .979

nm, the method that

t 1l ti -.e eu'l' k t tt\bslca Ltl-q

Lit

L\>

LrI

l. tT

a) dross-oolar method

ffi errur'Line method-.j rnr methodd) XRD method

2. A group of rocks having the chain structure is the:

a)/tectosilicates Lec+,t r,-e 3

@ inosilicatest ,) sheet silicatesd) neosilicates

L \ ! 3 "T.3HJJAf#il3'lfffi[":frr.u

' Z*ttatii"". uuJ

"1il,'5ir',i{'J[ o -," t'(:

r'': a' )

a{ ;inru'md untliffiiG'' *

4i anF;il[!?, u"a orfg'frffs'6"

4. A carbonate which is mud-supporled and contains more thana\,/carbonate m rrdstone

6);;;b;;ui.,'u.t.rton" 7 ta\'t ,) packestone grw^ir s'pp" r te{ cal n"'d ) tt *'d-

d) grainstone 11 y^in e'fra"le'! c Kr.3 --d)

5. Tlp typical mineral assemblage present in a phyllite is:

ffi grrurt , biotite, plagioclase, garnet and kyaniteb) quartz, biotite, plagioclase, garnet and sillimanitec) quartz, chlorite, muscovite, plagioclased) qu.artz, chlorite, muscovite, plagioclase and olivine

10% grains is:

tru ec&,esdbne

Anrt oJ r hnc

-1-

?JevYtz

<"{ u2xe*,2{

,? - i,-l.l(*'1. -r*.*t ".. *'{,rP'

iqr/ 1 a;o Lcz5-_gy]

(:*' n p tU.

"*r-"# Lu *i {ft" < r\ 4i or ( c< - ?i )

{ciclic volcadic rocks tend to have more slass

L

L \LI ,ii:idic voliadic rocks tend to have more glass than badic volcanic rocks becausc:

ri i ir:,igrnas in acidic rocks are poor in silica and alkalies and they tend to be

ri,rrre fluid.,: -nlrgr]r&s in acidic rocks are poor in silica and they tend to be more viscous

P ,.rrgmas in acidic rocks are rich in silica and alkalies and they tend to be ttrorc

VlSCOLIS

.it magmas in acidic rocks are rich in silica and alkalies and they tend to be Irtorc

fluid

L11 7. When numerous grains of various minerals in random orientation are completell'' en tosed with large optically continuous crystals of different composition. it has a:

ffi poikililic texture c

'Y) graphic textttre '4e2c) myrmekitic textvre,//d) spherulitic texture r^liat of<A^l<

'; \q 8. A rudite that is composed of poorly sorted, mud to gravel-sized sediment,

commonly with angular clasts is:

a) an agglomerateb)/conglomerate

@ ^diamictite' d) a breccia

9. Individual crystals in a rock which are so small that they are not visible w-ithout

the aid of a microscope are described as having :

a)/a phaneritic texture ' I '

@ u"aphanitic textureI c) a PorPhYritic texture

Lr(

d) a cryptocrystalline texture

10. A sandstone which has 60oh quartz,30% feldspars and 10% rock fragments isa) a quarlz arenjteb) an orthoquartzitec1/alithic arenite^ it4 7' 6ea,1t ?a r- 1:* l4tpc,t tro i' n''tt fft^^&r

6j unarkosb arenite

I 1. A coarse-grained igneous rock having a composition of 30% quarltz, 45% K-{bldspar (alkali feldspar), 15o/oplagioclase, 8% biotite and2o/o hornblende is

classified as :

a) a basaltb) ay'unitec1 /diorrte

@ ^granite

L*t\edg - b\* / e\n-"lz

1ru tiF

t ,rf

)

-2-

LC 12. Atthe highest grade of metamorphisni ol .r basalt parent rock, amphiboles are

replaced by pyroxenes and the rock uhich i: indistinctly lbliated is called :

a) an amphibolite6XTu sranulite

6 u[.reissd) an eclogite

I f I 3. A spotted slate indicates that the rock is nretamorphosed thermally. The spots are:e Q incipient chlorite

' b) jncipient biotite

@ incipient ch iastol itet d) incipient gamet

( 141 A mineral which has a distinctive 'Berlin biue' interf-erence colour and fan-trr---l shaped aggregates is:

a) biotiteb) dementine

@ ciloited) sillimanite

,l-tt15. Crystals having a grain size beqleen 5mm and 3cm is described as:

ar.,fine-srained E.lw - 6.v{ hp^ffi ,ourrr-grained 0't' I

6 very coarse-grained 1-- I ii4rv)

d) *.di.,--g.uin.d o.?-f - o'f

---End of paper---

a--l -

L \t+

,:d, *"'.*"{r-

:-"j -id' rrr-.t'- {;'&f- !t..'ri;-,*:,r,Ei{. *ijrj

, r r:- ,, -.,- )s,a ,**,1*n .:r-*-+ i in..=--!J -'.i. . .t * r i+ **Fio'r."*-y',i-*;FS-+'* A rtu. drK,u"

.&<r"t/* {r., *.i *;\,, -< f\ €,o. C 6s - ?i) Srittiifi'' tr, I < 1;o Ltts--3 )i. i,l': volcaiiic rocks tend to have more glass than basic volcanic rocks becausc.

i i : , .imas in acidic rocks are poor in silica and alkalies and they tend to bc

. rre fl,rid, - r. rgnras in acidic rocks are poor in silica and they tend to be more viscous

ffi , Ltgmns in aciclic rocks are rich in silica and alkalies and they tend to be Ittorc

r'lSCOtlS

.,t; inagmas in acidic rocks are ricli in silica and alkalies and they tend to be tlorclluid

{.,1-.. 7. When nllmerous grains of various minerals in random orientation are completell'ery;losed lvith large optically continuons crystals of different composit:ion. it has a:

@l) poikilitic texttrre c'Y) graphic lexttrre '4A2

c) myrmekitic texture//d) spherulitic textttre r^!."1 ^6r<71<

. \9 S. A ruclite that is composed of poorly sorted, mnd to gravel-sized secliment,

commonly with angular clasts is:

a) an agglomerateb1 v{conglomerate

6 udiarnictitevJ''d) a breccia

9. Individual cr.vstals in a rock i,vhich are so small that they are not visible r.vithout

the aid of a microscope are described as having :

a) /a phanerit ic texture

@ u" aphanitic texturc7 c) a porphyritic textttre

d) a cryptocrystalline texture

L t ( 10. A sandstone which has 60% quartz,3O% feldspars and 10% rock fragments is :

a) a quaflz arenileb) an orthoquartziteC]2lalithiC areniten

;tA /' Qva,lt 3a i. F< (4tput t1Q 'r' ru'ck f'Vu-^+

,@ o"arkose arenite

' ' + 1 L A coarse-grained igneous rock having a composition of 30% quatlz,45ohK-' feldspar (alkali feldspar), 15% plagioclase, 8% biotite andZYo homblende is

classified as :

a) a basaltb) ay'unitec) ,zi diorite/.x

${) a grrnlte

Lr^h Vd €

tr-"r UiP

\ri lJ / r\"t'lz_1 -

., .\1 12. At. the highest grade of metamorphisnr ot'.r besalt parent rock, amphiboles areu replaced by pyroxenes and the rock uhich is indistinctly loiiated is called :

a) an amphibolite

W^granulitec) a gnelss

d) an eclogite

| {f 13. A spotted slate indicates that the rock is rretanrorphosed thermally. The spots are:

a) incipient chloriteb) incipient biotite

@rncipienr c h i a sto I i tet d) incipienl gamet

( tai A mineral which\--l shaped aggregates

a) biotiteb),{ementine

ffi "r,iorit_d) sillimanite

has a distinctive 'Berlin blue' interference colour and fan-is:

---End of paper---

,l-lt15. Crystals having a grain size bettryeen 5mm and 3cm is described as:

a).,fine-srained 3'tl,r - ,t'* &t\AA'|

ffi ,ourJr-grained (,)'t * |5 very coarse-grained 1- l h^rv1

d) medium-grained a.?-t - o'f

-J-