Orogenic gold mineralisation in the Archean North Atlantic craton, southern West and South-West

Greenland

Jochen Kolb1, Denis M. Schlatter1, Annika Dziggel2, Alexander F.M. Kisters3

¹Department of Petrology and Economic Geology, Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350

Copenhagen K, Denmark2Institute of Mineralogy and Economic Geology, RWTH Aachen

University, Wüllnerstr. 2, 52064 Aachen, Germany3Department of Earth Sciences, Stellenbosch University,

Matieland 7602, South Africa

Mineralizing system of orogenic gold deposits

Groves et al. 1993

Main devolatilization440 – 520°CPhilipps and Powell 2010

SOURCE ROCK

CONDUIT

Fluid/wallrock reactions

Au deposition

increasing intensitiy of alteration

Dispersion

Diffusion

hydrothermal alterationRidley et al. 1996

Gold production vs. gold ages

Gol

dfar

b et

al.

2001

North Atlantic craton

Schematic geologocal

map of Greenland

Geological map of South-West Greenland

Paamiut gold province

Tartoq gold province

Characteristics of gold mineralization

Paamiut gold province• 5 occurrences; 40 km

strike• Auriferous quartz veins in

higher-order structures• Au-only + As, W, Mo, Bi• Ore mineralogy: Po-Apy-

Ccp• Hydrothermal alteration

mineralogy– Proximal Hbl– Distal Qtz-Hbl/Oam-Bt-Tur-

Ank ± Grt, Ms, Cal– Sulfide-poor (< 5 vol.%)

Tartoq gold province• ≥ 3 occurrences; 40 km

strike• Auriferous quartz veins in

higher-order structures• Au-only + As, Ag, W, Sb, Bi• Ore mineralogy: Apy-Ccp-

Py• Hydrothermal alteration

mineralogy– Qtz-Ms-Chl-Ank– Sulfide-poor (< 5 vol.%);

except BIF

The Paamiut gold province: structure

NWAkuliaq

SEMellembydgen

Akulleq glacier

Au AuAuAu Au

mesozonalgold metamorphosedgold

• Metamorphic dates– 2850 – 2830

Ma: Paamiut orogeny

– 2760 – 2740 Ma: Tasiusarsuaq orogeny

The Tartoq gold province: structure

±Au

Au

Au

±Au

• Metamorphic dates– 2850 – 2830 Ma: Paamiut

orogeny– 2760 – 2740 Ma:

Tasiusarsuaq orogeny

Geological map of southern

West Greenland

Bjørnesund occurrenceCa. 2840 Ma

Sermilik prospect

Characteristics of gold mineralization

Sermilik gold prospect• ≥ 2 locations; 4 km strike• Ca. 2740 Ma• Auriferous quartz veins in

folds and shear zones• Gold-only + Ag, As• Ore mineralogy: Po-Ccp-Py-

Ilm-Mag• Hydrothermal alteration

mineralogy– Qtz-Grt-Bt-Kfs (660°C, 7.5-8

kbar)– Sulfide-poor (< 5 vol.%)

Tectonic model for the Sermilik prospect: Tasiusarsuaq orogeny

Grædefjord

Ilivertalik2800 Ma

Sermilik2740 Ma

AuAuTasiusarsuaq terrane2800 - 2740 Ma

Færingehavn &Tre Brødre terranesundiff.

Qarliit Nunatthrust2720 Ma

N S

Geological map of

southern West

Greenland

Characteristics of gold mineralization

Godthåbsfjord gold province

• ≥ 5 prospects; 110 km strike• 2985 Ma, 2715 Ma, 2630 Ma• Gold-quartz±carbonate

veins• Ore mineralogy: Po-Ccp-Apy-

Py-Ilm-Mag• Hydrothermal alteration

mineralogy– Inner Qtz-Hbl ± Bt– Proximal Qtz-Grt-Bt-Hbl-Sil

(530-630°C, 4-6 kbar)– Distal Bt ± Grt– Sulfide-poor (< 5 vol.%)

Tasiusarsuaq gold province

• ≥ 7 locations; terrane-scale

• Ca. 2675 Ma• Quartz veins ± Au• Ore mineralogy: Po-Ccp-Py-

Ilm-Mag• Hydrothermal alteration

mineralogy– Inner Qtz-Hbl ± Bt, Ep, Rt– Proximal Qtz-Grt-Bt-Hbl ±

Ms (650°C, 3.5-4 kbar)– Distal Bt ± Grt– Sulfide-poor (< 5 vol.%)

Str

uctu

re o

f th

e

God

thåb

sfj

ord

an

d

Tasiu

sars

uaq

gold

pro

vin

ces

Model for 2670-2580 Ma orogenic gold Akia terrane

Atane

q fa

ult

Ivin

ngui

t fau

ltQussuk

Storø2630 Ma

Qilanngaarsuit< 2715 Ma, > 2560 Ma

Bjørneøen

Store Malene

Isua

Kapisilik terrane

Tasiusarsuaq gold province

2670-2610 Ma

2660

-260

0 M

a

Tasiusarsuaq terrane

2650-2580

Ma

Qôr

qut

2560

Ma

Færingehavn &Tre Brødreterraneundiff.

2670 Ma

Godth

åbsfj

ord

gold

pro

vince

Conclusions

• Several stages of orogenic gold mineralization• ca. 2990 Ma Isukasia orogeny• 2850 – 2830 Ma Paamiut orogeny• 2800 – 2740 Ma Tasiusarsuaq orogeny• 2720 – 2700 Ma Tre Brødre orogeny• 2670 – 2580 Ma Kapisilik orogeny

• Hypozonal orogenic gold– Tasiusarsuaq gold province: single-stage – no potential– Godthåbsfjord gold province: multi-stage (?) – small deposits

• Mesozonal orogenic gold– Paamiut gold province – not explored, good potential– Tartoq gold province – not explored, good potential