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‘Golden Opportunities’‘Golden Opportunities’
Twin LakesB-zoneTwin LakesB-zone
Rice Lake mineBissettRice Lake mineBissett
Manitoba Mining & Minerals Convention 2004Manitoba Mining & Minerals Convention 2004
San Gold# 2 zoneSan Gold# 2 zone
Archean orogenic lode gold in the Superior Province of Manitoba:
Recent results on structural controls, relative timing and orogenic context of mineralization
ArcheanArchean orogenicorogenic lode gold in the lode gold in the Superior Province of Manitoba:Superior Province of Manitoba:
Recent results on structural controls, relative timing Recent results on structural controls, relative timing and and orogenicorogenic context of mineralizationcontext of mineralization
Scott AndersonManitoba Geological Survey
Scott AndersonManitoba Geological Survey
‘Golden Opportunities’‘Golden Opportunities’
OutlineOutline
• Superior Province: geological overview• Superior Province: gold endowment• Orogenic lode gold deposits: characteristics• Recent results:
1) Stull Lake belt (Twin Lakes)
2) Rice Lake belt (San Antonio)
• structural controls• relative timing• orogenic context
• Preliminary conclusions;future plans
‘Golden Opportunities’‘Golden Opportunities’
Superior ProvinceSuperior Province
Goudalie
Minnesota River Valley
Wabigoon
Uchi
WawaAbitibi
Bienville
English R.Winnipeg R.
Pikwitonei
Quetico
Berens R.
Bird R.
Island L.
Molson L.
Oxford L. - Stull L.
Kapuskasing
Opatica
Opinaca
Minto
Ashuanipi
Quetico
Wawa
Douglas Harbour
Utsalik
La Grande
Northern Superior
Sugluk
Pontiac
500Kilometres
Goudalie
Minnesota River Valley
Wabigoon
Uchi
WawaAbitibi
Bienville
English R.Winnipeg R.
Pikwitonei
Quetico
Berens R.
Bird R.
Island L.
Molson L.
Oxford L. - Stull L.
Kapuskasing
Opatica
Opinaca
Minto
Ashuanipi
Quetico
Wawa
Douglas Harbour
Utsalik
La Grande
Northern Superior
Sugluk
Pontiac
500Kilometres
‘Golden Opportunities’‘Golden Opportunities’
Superior Province:Orogenic Lode Gold DepositsSuperior Province:Orogenic Lode Gold Deposits
HGZ, Red Lake mineHGZ, Red Lake mine
500Kilometres
North Caribou Lake
Pickle Lake
Red Lake
Rice Lake
Hollinger- McIntyre
HemloVal d’Or
Kirkland Lake
Chibougamau
Malartic
‘Golden Opportunities’‘Golden Opportunities’
Manito
baOntar
io
Wabigoon
Uchi
Winnipeg R.
Berens River
Oxford-Stull
LakeWinnipeg
Northern Superior
English R.
Quetico
WawaLake
pSu erior
Island L.
Munro
3.5- 2.81 Ga Northern Superior superterrane 3.0 - 2.87 Ga North Caribou terrane3.17 - 2.81 Ga Winnipeg River terrane
Mainly oceanic affinity
Mainly continental affinity
Meta-sedimentary belt
Granitoid rocks
> 2.8 Ga continental terranes and isotopic influence
Greenstone belts
200 km
NW Superior ProvinceNW Superior Province
OLG deposits>50,000 oz. Au
>1,000,000 oz. Au
OLG deposits>50,000 oz. Au
>1,000,000 oz. Au
(Percival et al., 2000)
‘Golden Opportunities’‘Golden Opportunities’
10,000
100,000
1,000,000
10,000,000
Red La
ke
Musse
lwhit
eMad
sen
San Anton
ioPick
le Cro
wCoc
henou
rMcK
enzie
Centra
l Patr
icia
Twin
Lakes
Howey
Lingman
Lake
Berens
Rive
rHas
aga
Little
StullDon
a Lak
e
Starrat
t Olse
nGod
s Lak
e
Oxford
Lake
Centra
l Mb.
High Rock
Is.
Gunnar
Packs
ack
Ogama
Sachigo
R.
NW Superior Province:Orogenic Lode Gold deposits
NW Superior Province:Orogenic Lode Gold deposits
(>50,000 oz. Au)
**Over 41 million ouncesdiscovered to date
‘Golden Opportunities’‘Golden Opportunities’
NW Superior Province:Manitoba OLG deposits
NW Superior Province:Manitoba OLG deposits
Lake Winnipeg
Thompson
Winnipeg
200 km Rice Lake
Gods Lake
Island Lake
Stull Lake
Oxford Lake
**Over 3.5 million ouncesdiscovered to date
(>50,000 ounces)
191560,000Rice LakeOgama
191790,000Rice LakePacksack
1921100,000Rice LakeGunnar
1934120,000Island LakeHigh Rock Is.
1915140,000Rice LakeCentral MB
1986150,000Oxford LakeOxford Lake
1932160,000Gods LakeGods Lake
1986220,000Stull LakeLittle Stull
1989530,000Stull LakeTwin Lakes
19111,970,000Rice LakeSan Antonio
Discovery year
Ounces Au
Greenstone belt
Deposit
‘Golden Opportunities’‘Golden Opportunities’
Orogenic Lode Gold Deposits:Characteristics
Orogenic Lode Gold Deposits:Characteristics
• High degree of structural control
• Accretionary plate margins• Granitoid - greenstone terranes• Spatially associated with regional-scale shear
zones marking major terrane boundaries• Regional greenschist-facies metamorphism• Fe-rich rock-types (chemical traps)
• Evidence for syn to late-kinematic emplacement
• Quartz-carbonate vein systems
‘Golden Opportunities’‘Golden Opportunities’
Orogenic lode gold deposits:Structural analysis
Orogenic lode gold deposits:Structural analysis
• Relative timing• Processes and controls
• Orogenic context
DEPOSIT GENESIS
FORMULATE EXPLORATION STRATEGIES
Detailed structure analysis provides constraints on:
‘Golden Opportunities’‘Golden Opportunities’
NW Superior Province:MGS structural mapping
NW Superior Province:MGS structural mappingMan
itoba
Ontario
Wabigoon
Uchi
Winnipeg R.
North Caribou
Oxford-Stull
LakeWinnipeg
Northern Superior
English R.
Quetico
WawaLake
pSu erior
3.5- 2.81 Ga Northern Superior superterrane 3.0 - 2.87 Ga North Caribou terrane3.17 - 2.81 Ga Winnipeg River terrane
Mainly oceanic affinity
Mainly continental affinity
Meta-sedimentary belt
Granitoid rocks
> 2.8 Ga continental terranes and isotopic influence
Greenstone belts
200 km(Percival et al., 2000)
(T13)
(GS-20)
‘Golden Opportunities’‘Golden Opportunities’
Gods Lake – Stull Lake regionGods Lake – Stull Lake region
Gods LakeGods Lake
Twin LakesTwin Lakes
Little Stull LakeLittle Stull Lake
‘Golden Opportunities’‘Golden Opportunities’
Sharpe Lake - Twin Lakes:Provisional summary of deformation
Sharpe Lake - Twin Lakes:Provisional summary of deformation
Late-orogenicshortening?Brittle > ductile faultsD4
Dextral transpression; terminal KenoranOrogeny
Crustal-scale, greenschist-faciesshear zones; SLWSZ and TLSZ (late)
NW-SE
Mylonitic S3 in east-trending, ductile > brittle, dextral shear zones; WSW-trending S3crenulation cleavage; F3 folds
D3
Collisional orogenesis; early KenoranOrogeny; sinistraltranspression?
Belt-scale isoclinalF2 folds; High-T shear zones on belt margins; SLWSZ and TLSZ
NE-SW
Regional S2 foliation; isoclinal, doubly-plunging F2 folds; steep L2stretching lineation; ductile shear zones (north over south shear)
D2
Onset of collisionalorogenesis?Early thrust faults??Bedding-parallel S1 foliation; rare
isoclinal F1 foldsD1
Tectonic significanceRegional structureShortening direction
Deformation structures
‘Golden Opportunities’‘Golden Opportunities’
0m
200m
400m
91-61
TL-03-117
TL-03-120
TL-03-118
TL-03-108
TL-03-107
TL-03-105
TL-03-103 “A” ZONE
“B” ZONE
“C” ZONE
Mafic volcanic rocks; gabbroGreywacke, mudstone; iron formationFelsic - intermediate tuffPlagioclase-phyric andesiteFeldspar-porphyry dike
LEGENDFluvial sedimentary rocks
Section Looking WestSECTION 14850 E
0m 50m 100m
Twin Lakes Deposit:Cross section
Twin Lakes Deposit:Cross section
‘Golden Opportunities’‘Golden Opportunities’
Twin Lakes Deposit:Longitudinal section
Twin Lakes Deposit:Longitudinal section
200m
400m
200m
400m
C Zone
Fall 2004 Drilling Area
200m
400m
200m
400m
B Zone1.0 km
Fall 2004 Drilling Area>10.00 g/t Au/m
2003 DrillingPre 2003 Drilling
Winter 2004 Drilling
Hole ID / metre g/t Au
5.00 - 10.00 g/t Au/mFall 2004 Drilling
Seeber West Zone Twin Lake ZoneSeeber Central/Twin West Zone
‘Golden Opportunities’‘Golden Opportunities’
Twin Lakes Deposit:mineralization style
Twin Lakes Deposit:mineralization style
TL04-190(C-zone)
• Later quartz-albite alteration(competent)
• Brittle failure• Structural permeability• Syn-kinematic veins
(qtz-aspy + Au)
• Early sericite-ankerite alteration(incompetent)
‘Golden Opportunities’‘Golden Opportunities’
GSC04-5B-zone
Twin Lakes Deposit:relative timing
Twin Lakes Deposit:relative timing
Syn - D2 mineralization
Syn - D2 mineralization
GSC04-5
(B-zone)
GSC04-5
(B-zone)S2 L2L2
‘Golden Opportunities’‘Golden Opportunities’
Rice Lake beltRice Lake belt
Platform-rift sequence ( )ca. 2.99 Ga
Volcanic rocks ( )ca. 2.72-2.73 Ga
Tonalitic intrusive rocks (2.7 to 3.0 Ga)
Siliciclastic rocks (ca. )2.7 Ga
English River terrane
Paleozoic
Uchi terrane
North Caribou terrane
Paragneiss, orthogneiss granite (ca. 2.66-2.69 Ga)
Limestone, quartzite
Tonalite, quartz diorite (ca. 2.73 Ga)
Volcanic rocks ( )ca. 2.87-2.90 Ga
Rice Lake belt
50°45'
95°15'
96°15'
51°00'
LakeWinnipeg
Ross River pluton
Wallace assemblage
Lewis-Storey assemblage
Man
itoba
Ont
arioManigotagan
Shear Zone
Wanipigow Shear Zone
Black Is.
0 10 20
kilometres
Geological contact
Shear zone
Gold occurrence; gold deposit51°15'
‘Golden Opportunities’‘Golden Opportunities’
Central Rice Lake belt:Provisional summary of deformation
Central Rice Lake belt:Provisional summary of deformation
?Open folds at Rice LakeOpen, north-trending F6crenulations
E-WD6
Orogen-scale dextral transpression; terminal collision?
Dextral transcurrentshear zones
WNW- to NNW-trending high-strain zones; L5 lineation; F5folds; S5 shear-band cleavage
NNW-SSED5
Early dextral transpression??
Regional SW- to WSW-trending S4; L3
4 intersection lineation; Z-asymmetric F4folds
NW-SED4
Crustal thickening; main-stage KenoranOrogeny
Macroscopic folds; Gold Creek syncline and Horseshoe Lake anticline
Regional NW- to WNW-trending S3; L3 stretching lineation; upright F3 folds
NNE-SSWD3
Basin inversion; early Kenoran Orogeny
Thrust faultsLocal, weak, layer-parallel S2foliation
?D2
Intraoceanic accretion?TiltingNone observed?D1
Tectonic significanceRegional structureDeformation structuresShortening direction
‘Golden Opportunities’‘Golden Opportunities’
San Antonio mine geologySan Antonio mine geology
Shaft
Projection of workings
Geological boundary(approx., extrapolated)
Townsite section
Round Lake section
San Antonio assemblage
Felsic volcanic sandstone and conglomerate
Gabbro
Pillowed basalt, minor volcaniclastic rocks
Dacite tuff breccia
Heterolithic conglomerate
Quartz arenite, polymictic conglomerate
Younging direction
Hares Is.
San Antonio sill‘Unit A’
A'
A
D
CB
A
(projected)
(projected)
(projected)
Hotel
Rice Lake
Angular unconformity
2000metres
San Antonio mine
Disconformity
(Modified from Poulsen et al., 1996)
MelagabbroLeucogabbro
‘Golden Opportunities’‘Golden Opportunities’
Level 15, San Antonio mineLevel 15, San Antonio mine
38-type
38-type
16-type16-type
‘Golden Opportunities’‘Golden Opportunities’
San Antonio-type vein systems:relative timing
San Antonio-type vein systems:relative timing
38-type
38-type16-ty
pe
16-type 16-type
16-type
S3-S4-S5
Syn to post-D5mineralization (?)Syn to post-D5
mineralization (?)
‘Golden Opportunities’‘Golden Opportunities’
Conclusions and future workConclusions and future work
• SLB and TLB - complex structural evolution
• Syn-tectonic vein (+Au) emplacement• TL and SA deposits - high degree of structural control
Twin Lakes deposit• syn-D2• early tectonic
San Antonio deposit• syn to post-D5 (?)• late tectonic
What is the absolute ageof mineralization?
What is the absolute ageof mineralization?
Re-Os (apy)Re-Os (apy) U-Pb (ti, mz)U-Pb (ti, mz)• How did the deposits form?
• Where should we look for more?
• How did the deposits form?
• Where should we look for more?