Scheelite in Malene supracrustals of the Ivisârtoq area, southern West Greenland

Abstract

In 1982 the first traces of scheelite were found in the Godthåbsfjord area in heavy mineral concentrates from stream sediments. The same year the first in situ scheelite occurrences were found. In the folIowing year a stream-sediment sampling programme was carried out in the area and in the area to the south. This programme demonstrated that scheelite is a frequent constituent of the 3800 m.y. old Isua supracrustal rocks and in the 3300 to 3000 m.y. old Malene supracrustals, whereas the gneisses in the Nuuk/Godthåb area are barren. The Malene supracrustal rocks, which form extensive outcrops, are the larger of the two supracrustal belts, and outcrops are found scattered over an area of at least 35000 km2. During the field season of 1986 stream sediment samples were collected in the Ivisârtoq area of the inner Godthåbsfjord region, and they proved to contain high amounts of scheelite. It was thus decided to carry out field work with ultra-violet light, but early snow precipitation prevented any field work. During the field season the folIowing year, another attempt was made to carry out field work with ultra-violet light in the lvisârtoq area.