During the GEUS field season in summer 2009, a research team of two geologists visited the area north of Sermilik to study the potential for hydrothermal gold mineralisation. A narrow quartz vein system was studied at 51°00.1'W and 63°31.9'N. The veins are 10-20 cm wide and locally several parallel veins form a laminated texture. The veins are near-vertical, parallel to the main foliation trending northwest-southeast and can be followed over several hundred meters along strike.
Two veins were sampled and analysed for gold. An in situ rock sample of one of them yielded 6370 ppb Au, whereas the other vein recorded only 5 ppb Au. Gold was also detected by the Scanning Electron Microscope (SEM) in a polished thin section of the former vein. The veins are surrounded by 20-50 cm wide alteration halos containing biotite, quartz, garnet, pyrrhotite, pyrite, and chalcopyrite. A combined vein and alteration rock sample is slightly enriched showing 17 ppb Au. GEUS is currently undertaking more research work and more geochemical analyses in a joint project between GEUS and the Bureau of Minerals and Petroleum, Greenland.
Although only one of the veins shows high gold values, the area is regarded as promising for further gold exploration. A gold content of 6 g/t is high and the sampling technique by using 1-2 kg samples is selective, which may result in erratically low gold values due to the nugget effect of gold. Systematical sampling of veins and alteration zones is needed to evaluate the potential of this new lode gold occurrence.
Jochen Kolb, GEUS
Phone: +45 38 14 20 00