The chromite deposits of the Fiskenæsset region, West Greenland

Abstract

The chromite deposits of the Fiskenæsset region occur in anorthosites, which together with intercalated pyribolites (hypersthene amphibolites) and subsidiary pyroxenites and peridotites occur in the gneisses as horizons belonging to a folded and metamorphosed stratiform complex which has a maximum thickness of 2 km. The chromite occurs in horizons which average 0.5 - 3 m in width, reaching a maximum of 20 m, and consist of alternating anorthosite and chromitite layers, usually between 0.5 and 10 cm wide. Chromite horizons occur in almost all of the anorthosite horizons in the region which have a minimum exposed length of 125 km. 175 X-ray fluorescence analyses show that the Cr₂O₃ content of the chromite varies between 26% and 36%, averaging 32.7%. The total iron oxide content varies between 28% and 42%, averaging 31. 8% (as FeO), with the result that the Cr:Fe ratio varies between 0.66 and 1.05, averaging 0.93. The chromite has a high V₂O₅ content varying from 0.2% to 0.5% with an average value of 0.3%. The chromite horizons occur along the shores of the fjords or only a few kilometres from the coast in easily accessible terrain that rarely exceeds 500 m in altitude. Fiskenæsset harbour is ice-free for the whole year.