Geochemistry and petrology of gold-bearing hydrothermal alteration zones on Qilanngaarsuit, southern West Greenland

Martin Koppelberg,Denis Martin Schlatter,Franz Michael Meyer,Jochen Kolb,Annika Dziggel

doi:10.34194/geusb.v28.4723

Abstract

During field work in 2008, the Geological Survey of Denmark and Greenland investigated the gold potential of hydrothermal vein systems in the Nuuk region of the Archaean North Atlantic craton. A new gold occurrence was discovered on the island of Qilanngaarsuit, 35 km south of Nuuk. Two cross sections through hydrothermal alteration zones, that locally contain up to 672 ppb Au, were mapped and sampled in detail. In this study, we present petrological and geochemical data in order to constrain the conditions for ore formation and transport of elements during fluid–rock interaction.

Highlights

Geological settingQilanngaarsuit in southern West Greenland (Fig. 1) is situated in the Godthåbsfjord gold province, a c. 20 km by 150 km wide, NE-trending sector along the Ivinnguit fault system
During field work in 2008, the Geological Survey of Denmark and Greenland investigated the gold potential of hydrothermal vein systems in the Nuuk region of the Archaean North Atlantic craton
The Ivinnguit fault, situated north of the island, is a deep-crustal shear zone, which formed during terrane amalgamation and it represents the border between the Færingehavn and Akia terranes (Nutman & Friend 2007)

Summary

Geological setting

Qilanngaarsuit in southern West Greenland (Fig. 1) is situated in the Godthåbsfjord gold province, a c. 20 km by 150 km wide, NE-trending sector along the Ivinnguit fault system. 20 km by 150 km wide, NE-trending sector along the Ivinnguit fault system. Several gold occurrences such as Storø, Qussuk, Bjørneøen and SW Isua have been described from this sector (Garde et al 2012; Scherstén et al 2012; Kolb et al 2013). The Ivinnguit fault, situated north of the island, is a deep-crustal shear zone, which formed during terrane amalgamation and it represents the border between the Færingehavn and Akia terranes (Nutman & Friend 2007). The gold-bearing quartz veins are hosted by amphibolites in the central part of the island and surrounded by approx. One sample from a hydrothermal alteration zone surrounding the veins contains up to 672 ppb Au and several other vein and alteration zone samples have elevated Au contents (> 20 ppb Au; Kolb et al 2009)

Profile A

Petrology and geochemistry

Ni Co Sc

Discussion and conclusion