Gold occurrences in supracrustal rocks of the Nuuk region, West Greenland

In the Nuuk region two generations of Archaean supracrustal rocks occur. The 3.760 Ga Isua supracrustal helt hosts quite extensive horizons of banded iron-formation. Grab samples of silicate facies iron-formation yield gold values of 1 ppm. Grab samples of ether facies of iron-formation yield grades of gold in the arder of 0.1 ppm.

In the younger Malene supracrustal rocks stratabound sulphide horizons are found. These horizons are locally tens of metres wide and can be traced intermittently for kilometres. Analysis of dril! cores yield gold contents up to 2.5 ppm over 0.2 m. In the Malene supracrustal rocks an assemblage is found consisting of ultramafic and mafic lavast metasedimentst tourmalinites and stratabound scheelite mineralizations. Anthophyllite-gedrite zones locally rich in sulphides are locally found. These zones are interpreted as hydrothermal alteration zones. Scattered gold anomalies have been found associated with scheelitet and heavy mineral concentrates of stream sediments from a regional sampling programme indicate a positive correlation between gold and scheelite.

The analytical data as well as some of the ether data presented in this open filereport have been extracted from the GREENLAND MINERALIZATION DATA BANK. This data base contains detailed information on mineral occurrences in the Nuuk region; and eventually all available information on mineral occurrences in Greenland will be stored in this data base.

It should be borne in mind that as yet no prospecting for gold has been carried out in the Nuuk region. All gold anomalies discussed in this report have been found as "spin off" from ether types of investigation.