Metalogenia dos Greenstone-Belts Canadenses: Ênfase nos Depόsitos

de OURO

Gema R. Olivo

SIMEXMIN 2012

Ouro Preto

Metallogeny of the Archean Canadian Greenstone Belts:

Emphasis on GOLD DEPOSITS

Gema R. Olivo

SIMEXMIN 2012

Ouro Preto

AGRADECIMENTOS/ ACKNOWLEDGMENTS

• PROF. ONILDO J. MARINI, ADIMB AND SIMEXMIN

ORGANIZING COMMITTEE

• Benoit Dubé and Patrick Mercier-Langevin for

great discussions on Canadian Archean Gold

Deposits

CANADIAN MAJOR DEPOSITS TYPES

Lydon, 2007

/ Archean

Lydon, 2007

GOLD: greenstone-hosted Cu-Zn (Au): VMS Cr, Ni, PGE, Ti in mafic- Ultramafic rocks Diamonds in Kimberlites

J. Mungall talk

GOLD PRODUCTION + RESERVES Canada : 9 280 t ( 7% global) Lode Gold: 5 510 t (59%) Superior province: 4 760 t Abitibi sub-province : 4 470 t

Lydon, 2007 Dube and Gosselin 2007

THE LARGEST ARCHEAN GOLD DISTRICTS

Robert et al., 2005

YE

LL

OW

NIF

E

423

LU

PIN

Slave Craton

+ 3

54 t

:

MAIN TYPES OF GOLD DEPOSITS IN SUPERIOR AND SLAVE PROVINCES

• Gold-rich VMS deposits (2699-2694 Ma) – La Ronde-Penna, Horne

• Intrusion-related Gold Deposits: Dan Kontak and S. Catallani talks – Gold disseminated in sub-alkaline to alkaline rocks (2686 or younger):

Holloway, Holt-McDermott, KK, Upper Beaver – Porphyry-related: Cote Lake, Canadian Malartic

• Gold in veins and disseminations in volcanic, intrusive and sedimentary rocks (>< 2860 Ma: various ages, types) – Hollinger-McIntyre (overprinting early porphyry-style) – Sigma-Lamaque, Siscoe, Red Lake, Con-Giant – Musselwhite, Lupin, Eleonore (M. Gauthier Talk), (BIF-hosted)

• Hemlo-type

MAIN TYPES OF GOLD DEPOSITS IN THE ABITIBI SUPROVINCE

Dubé et al, 2007: Modified from Poulsen et al., 2000

SUPERIOR PROVINCE GOLD DEPOSITS

Robert et al., 2005

Benville

La Grande

Ashuanipi

Opinica

Opatica

ABITIBI

WAWA

UCHI

Hemlo

Red Lake

Percival, 2007 Percival, 2007

? ?

LODE GOLD DEPOSISTS IN ARCHEAN GREENSTON BELTS: REGIONAL CONTROLS

• In granite-greenstone belts: with juvenile and/or continental arc sequences

• Close to major regional structures – Suture zones, major breaks

• Close to unconformity and sedimentary units – Flysch-type or Molassa-type (Lode, Intrusion-related)

• Spatial associated with intrusive centers • In belts with ultramafic flows (komatiite) • Most in greenschists facies rocks but some in

amphibolite grade rocks

SUPERIOR PROVINCE GOLD DEPOSITS

Robert et al., 2005

Benville

La Grande

Ashuanipi

Opinica

Opatica

ABITIBI

SOUTHERN ABITIBI GOLD DISTRICTS

Modified from Dube and Gosselin, 2007

Poulsen et al. 2000

QC-QT VEINS

Porphyry + QC VEINS

AU-VMS

INTRUSION- RELATED + VEINS

Porphyry INTRUSION- RELATED: VEINS

INTRUSION- RELATED

EVOLUTION OF SOUTHERN ABITIBI

Monzonite and S-type granite

GOLD

MANTLE PLUMES

VOLCANISM:

PLUTONISM

D1 D2 D3

TIMISKAMING EVENT

SEDIMENTATION

2720 2700 2680 2660 Age (Ma)

Flysch Fluvial

Tonalite, diorite

Ultramafic to felsic

Granodiorite, syenite

2620 2580

?

VOLCANIC ARCS

VMS DS

? DS/St QC/QT LATE

SOUTHERN ABITIBI GOLD DISTRICTS

Modified from Dube and Gosselin, 2007

Poulsen et al. 2000

AU-VMS: La Ronde Horne

GOLD-RICH VMS DEPOSITS

Dubé et al., 2007

LA RONDE PENNA 43.45 Mt @ 4.23g/t Au, 52g/t Ag, 2.72% Zn, 0.32% Cu

SOUTHERN ABITIBI GEOLOGY

Thurston et al., 2008

LA RONDE-PENNA HORNE

LA RONDE-PENNA

• 43.45 Mt @ 4.23g/t Au, 52g/t Ag, 2.72% Zn, 0.32% Cu

• Hosted in felsic volcanic rocks of the Blake River Group (ToCA: youngest in the Southern Abitibi)

• Associated with massive sulfide lenses

• Alteration: aluminous- silicate Mn Garnet-biotite-muscovite

• Intensively deformed and metamorphosed to up amphibolite facies

• Associated elements: Au-Ag-Zn-Cu-Pb-As-Sb-Sn-B-Bi

La Ronde-Penna: Host-Rocks and

Alteration

Mercier-Langevin et al. 2007

• UPPER LEVELS (20N LENSES)

– FOOTWALL: Quartz-Mn-rich garnet-biotite-chlorite

– HANGINGWALL: Biotite-rutile/titanite-pyhhrotite-pyrite

• DEEPER LEVELS (20N LENSES)

– INNER: Quartz-kyanite-pyrite-(Au-bearing chalcopyrite)

– OUTER: Quartz-Zn-rich staurolite-sericite-garnet-biotite-pyrite

La Ronde: alteration and mineralization

Auriferous pyrite

Dubé et al., 2007 Mercier-Langevin, 2007

Stringer and disseminated

Massive pyrite, sphalerite, chalcopyrite, pyrrhotite, bornite, galena, gold

La Ronde GENETIC MODEL

Mercier-Langevin

et al., 2007

Associated metals: Au-Ag-Zn-Cu-Pb-As-Sb-Sn-B-Bi

Exhalative VMS + magmatic (epithermal)

SOUTHERN ABITIBI GOLD DISTRICTS

Modified from Dube and Gosselin, 2007

Poulsen et al. 2000

Timmins Porphyry + QC VEINS

• Size: 978 t Au

• Setting: Archean tholeiitic basalts intruded by pre-ore porphyry and albite-rich dikes.

• Form of gold mineralization: quartz-ankerite veins and pyrite-rich host rock (arrays, sheeted and sigmoidal veins) overprinting early Cu-porphyry mineralization

• Alteration: albite-carbonate-muscovite-pyrite

• Elemental Association: Au, Ag, W (Bi, Te, Cu); Au:Ag ~ 9

Hollinger-McIntyre

A = Aunor Delnite

B = Buffalo Ankerite

D = Dome

H = Hollinger

HP = Hoyle Pond

M = McIntyre

P = Pamour

V = Vedron

Timmins Camp

Bateman et al., 2008

Hollinger- McIntyre

Hollinger-McIntyre Geology

Modified from Smith et al., 1984

2708 Ma

McIntyre: Cu Mineralization

Disseminated copper mineralization in the

in albitized feldspar porphryry and

associated with sericite (phyllic alteration)

Melnik-Proud, 1985

• Early stage: porphyry-

style Cu-Au-Ag-Mo

mineralization

• 2672 Ma (Re-Os in

molybdenite)

• Coeval to albitite dikes

• Stockworks of quartz-

anhydrite-chalcopyrite-

pyrite-galena-

molybdenite overprinting

early phyllic alteration

(sericite + pyrite)

• Main stage of Au mineralization (veins)

– Quartz carbonate-pyrite (-tourmaline-albite-

hematite-scheelite-tetrahedrite) veins

• Mainly extensional veins

– Alteration:

• Proximal: iron carbonate-quartz (-sericite)

• Distal: chlorite-carbonate alteration

– Age: 2670 Ma : Re-Os in main stage

molybdenite

Hollinger-McIntyre: paragenesis

Hollinger

Mine

Burrows et al., 1993

0.5 m

Albitite dike

Choritized

2672 Ma

Ankerite

-albite-

qz vein

2670 Ma

McIntyre

Mine

Seritized

felspar-qz

porphyry

2689 Ma

Melnik-Proud, 1985

Hollinger-McIntyre Fluids

• Gold mineralization is associated with aqueous-carbonic fluids (3 to 24 mole % CO2)

• Mineralization occurred at T=400-470 C and at 5-12 Km

• Fluids with this composition could be derived either from metamorphic rocks or deep magmatic sources

(Smith et al., 1984, Economic Geology V.79, p. 1265-1285)

Superior Province Gold Deposits

Robert et al., 2005

Benville

La Grande

Ashuanipi

Opinica

Opatica

WAWA

HELMO

Hemlo Deposit • 760 t of Au: 95 million tones of ore averaging 8.0 g/t Au,

1.5 g/t Ag, 0.10% Mo and 13% barite

• Extends for 3.7 Km along strike and 1.5 Km down dip

• Hosted in felsic (~2695 Ma) sequences, porphrytic intrusion (2680 Ma) and sedimentary rocks (older)

• Unusual hydrothermal alteration: aluminosilicate (silimanite-kyanite) – potassic (K-feldspar-V-muscovite-biotite)

• Ore: disseminated, dismembered quartz bodins

• Elemental association: Au, Ag, As, Sb, Mo, Ba, V, Hg

• Very complex formation and deformation history

• Age of mineralization: ? 2680-2675 Ma

Muir, 2003

Hemlo

Deposit

Helmo Deposit

Muir, 2003

HOST ROCKS:

• Metasedimentary rocks

• Baritic metasedimentary rocks

• Quartz feldspar porphyry

• Mafic fragmental unit

ALTERATION:

• K-feldspar-quartz-muscovite-biotite (Kyanite-Sillimanite)

Hemlo Ore:

Thomkins et al. 2004

• Group I (5-20% in rock): • pyrite and molybdenite

(>95%), minor pyrrhotite, sphalerite, cinnabar and gold – Gold (up to 26.9% Hg and

19.1 % Ag)

• Group II (< 2% in rock): • mainly stibnite and

realgar with rare sulfosalts, tellurides and native gold and other mative minerals – Gold (up to 1 mm);

rimmed by native As and aurostibite (AuSb2)

Group 1

Hemlo: Genetic Model

1. Main gold mineralization is coeval with mantle-derived magmatism, which occurred during the major second deformation event, metamorphism and formation of sedimentary basin Magmatic fluids are source of fluids and some metals

Shear zones were the conduits for the fluids

Gold and other metals precipitated in compressional demains

2. Gold, Sb, Te, As were late remobilized as sulfide melts and were concentrated within extensional zones and veinlets during the progressive deformation

SUPERIOR PROVINCE GOLD DEPOSITS

Robert et al., 2005

Benville

La Grande

Ashuanipi

Opinica

Opatica

ABITIBI

WAWA

UCHI

Hemlo

Red Lake

Red Lake Gold Mine

• Red Lake and Campbell mines (RED LAKE) – a total of ~ 840 t of gold (past Production +reserves) – average grade of 21 g/t

• Hosted in the basalts of Balmer Assemblage (2999-2996 Ma)

• Various styles of alteration and mineralization • Two major auriferous events:

– 2723-2712 Ma: synchronous with major intrusions and D2 deformation

– < 2702 Ma: late coeval with intrusions or late thermal event

Red Lake: Geology of level 15-deposit

Dube et al., 2004

Dubé et al., 2004

Red Lake: Gold Mineralization

• Barren to low-grade banded colloform-crustiform Qz-Cb veins and conckade breccias

• Sulfide-rich veins and replacement style

• Carbonate ± quartz veins

• Magnetite-rich ore

• High-grade arsenopyrite-rich silicification (high-grade zone)

• Abundant visible gold coating and filling late fractures

Red Lake: Styles of Gold Mineralization

Twomey and McGibbon, 2001 and Dubé et al., 2004

Barren to low grade Replacement: Silicification with arsenopyrite and Qz-Cc veins

4508 oz/t Au

gold

MAIN TYPES OF GOLD DEPOSITS IN SUPERIOR AND SLAVE PROVINCES

• Gold-rich VMS deposits (2699-2694 Ma) – La Ronde-Penna, Horne

• Intrusion-related Gold Deposits: Dan Kontak and S. Catallani talks – Gold disseminated in sub-alkaline to alkaline rocks (2686 or younger):

Holloway, Holt-McDermott, KK, Upper Beaver – Porphyry-related: Cote Lake, Canadian Malartic (talk)

• Gold in veins and disseminations in volcanic, intrusive and sedimentary rocks (>< 2860 Ma: various ages, types) – Hollinger-McIntyre (overprinting early porphyry-style) – Sigma-Lamaque, Siscoe, Red Lake, Con-Giant – Musselwhite, Lupin, Eleonore (M. Gauthier Talk), (BIF-hosted)

• Hemlo-type

Percival, 2007 Percival, 2007

?

CONCLUSIONS

• There are MAIN STYLES of gold mineralization hosted in Archean Greenstone-belts

• They formed in distinct geological settings and by distinct processes during the evolution of the belt – Coeval with volcanism and related intrusions or

– Synchronously with various events of magmatism and/or

– Synchronous with regional metamorphism and deformation

• Successful exploration will required thoroughly understanding of the VARIOUS geological settings and processes by which they formed identify footprint

GOLD PRODUCTION BRAZIL VS CANADA 2006-2010

0

20000

40000

60000

80000

100000

120000

2005 2006 2007 2008 2009 2010 2011

Brazil

Canada

Data source: http://www.bgs.ac.uk/

Au (Kg)

World 2011: 2 540 000 Kg

8 th

12 th

GREAT POTENTIAL: VARIOUS TYPES OF

GOLD DEPOSITS

Thank you!

Red Lake High Grade Ore