Gold and platinum-group element anomalies in the Fiskenæsset stratiform anorthosite complex, West Greenland

Platinum group element (PGE) contents in the Fiskenæsset anorthosite complex show a distinct relation to specific lithologies. PGE appear in highest amounts in ultramafics, chromitites and in sulphide-rich parts of the anorthosite. Exploration by A/S Platinomino in 1969-71 revealed platinum grades in grab samples up to 2.4 ppm and up to 3.1 ppm gold. In addition up to 57 ppm silver was encountered in a grab sample of a chromite banded bronzitite.

During field season 1991 a team from the Geological Survey of Greenland (GGU) collected channel, chip and a few grab samples across those ultramafics which during the previous exploration had yielded gold and platinum anomalies. The samples were analysed by Activation laboratories Ltd. (Actlabs), Canada. Channe! sampling of a bronzitite which previously yielded values of 3 ppm Au, 0.6 ppm Pt, 3 ppm Pd and 57 ppm Ag in a grab sample, now yielded 59 ppb Au, 74 ppb Pt, 115 ppb Pd and <5 ppm Ag! The hest values obtained was a channel sample over two metres of ultrabasic rocks and basic rocks on a small island at the coast which ran 1.37 ppm gold, 4.6 ppm silver and 0.27 % copper over 2 metres. Check analyses were carried out on selected samples by Chemex Labs Ltd, Canada. The results are within the same order of magnitude.

Several of the chromitite horizons in the Fiskenæsset anorthosite complex are cut by up to metre wide fuchsite-chrome-epidote-bearing alteration zones associated with shear zones. A few zones were chip sampled and analysed for gold, platinum and palladium, but no values above detection limits were found.