Archean orogenic lode gold in the Superior Province of ... · ‘Golden Opportunities’‘Golden...

‘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


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


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


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


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)


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


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


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


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:


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)


Gods Lake – Stull Lake regionGods Lake – Stull Lake region

Gods LakeGods Lake

Twin LakesTwin Lakes

Little Stull LakeLittle Stull Lake

SW Stull Lake beltSW Stull Lake belt

SWSZSWSZ

TLSZTLSZ

Twin Lakesdeposit

Twin Lakesdeposit


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


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


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


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)


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


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'

Central Rice Lake beltCentral Rice Lake belt


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


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


Level 15, San Antonio mineLevel 15, San Antonio mine

38-type

38-type

16-type16-type


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 (?)


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?

Archean orogenic lode gold in the Superior Province of ... · ‘Golden Opportunities’‘Golden...

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