Composition and classification of chromites in the Fiskenæsset anorthosite complex

Abstract

Chromite compositions from about 30 different localities throughout the whole of the Fiskenæsset region were studied in detail with the microprobe. The samples were selected on the basis of Cr-Fe X-ray fluorescence analyses on chromite concentrates of 183 samples (Ghisler, in press) and after examination of a large number of polished sections. They are considered as presenting the complete composition range within the area. For a detailed presentation of methods and results the reader is referred to Ghisler (in press). Here only the main results are given of the composition of chromite in terms of the elements Cr, Al, Fe and Mg, which are necessary for their classification. Ten grains were assayed within each polished section, based upon measurements at several points in each grain. The results presented below are thus based upon the composition of about 300 grains, with a total of about 1000 point analyses.