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

Orogenic gold mineralisation in the Archean North Atlantic craton, southern West and South-West Greenland. Jochen Kolb 1 , Denis M. Schlatter 1 , Annika Dziggel 2 , Alexander F.M. Kisters 3

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

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  1. 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 EconomicGeology, GeologicalSurvey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark 2Institute of Mineralogy and Economic Geology, RWTH Aachen University, Wüllnerstr. 2, 52064 Aachen, Germany 3Department of Earth Sciences, Stellenbosch University, Matieland 7602, South Africa

  2. increasing intensitiy of alteration Fluid/wallrock reactions Au deposition Diffusion CONDUIT Dispersion SOURCE ROCK hydrothermal alteration Mineralizing system of orogenic gold deposits Ridley et al. 1996 Main devolatilization 440 – 520°C Philipps and Powell 2010 Groves et al. 1993

  3. Gold production vs. gold ages Goldfarbet al. 2001 North Atlantic craton

  4. Schematicgeologocalmap of Greenland

  5. Geologicalmap of South-West Greenland Paamiut gold province Tartoq gold province

  6. Characteristics of gold mineralization Paamiut gold province • 5 occurrences; 40 km strike • Auriferousquartzveins in higher-orderstructures • Au-only + As, W, Mo, Bi • Ore mineralogy: Po-Apy-Ccp • Hydrothermal alteration mineralogy • ProximalHbl • DistalQtz-Hbl/Oam-Bt-Tur-Ank ± Grt, Ms, Cal • Sulfide-poor(< 5 vol.%) Tartoq gold province • ≥ 3 occurrences; 40 km strike • Auriferousquartzveins in higher-orderstructures • 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

  7. The Paamiut gold province: structure • Metamorphic dates • 2850 – 2830 Ma: Paamiut orogeny • 2760 – 2740 Ma: Tasiusarsuaq orogeny

  8. The Tartoq gold province: structure ±Au ±Au Au Au • Metamorphic dates • 2850 – 2830 Ma: Paamiut orogeny • 2760 – 2740 Ma: Tasiusarsuaq orogeny

  9. Geologicalmap of southern West Greenland Sermilik prospect Bjørnesund occurrence Ca. 2840 Ma

  10. Characteristics of gold mineralization Sermilik gold prospect • ≥ 2 locations; 4 km strike • Ca. 2740 Ma • Auriferousquartzveins 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.%)

  11. Tectonic model for the Sermilik prospect: Tasiusarsuaq orogeny N S

  12. Geologicalmap of southern West Greenland

  13. Characteristics of gold mineralization Godthåbsfjord gold province Tasiusarsuaq gold province ≥ 7 locations; terrane-scale Ca. 2675 Ma Quartzveins ± 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.%) • ≥ 5 prospects; 110 km strike • 2985 Ma, 2715 Ma, 2630 Ma • Gold-quartz±carbonateveins • 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.%)

  14. Structure of the Godthåbsfjord and Tasiusarsuaq gold provinces

  15. Model for 2670-2580 Ma orogenic gold

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

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