Petrography of gneisses south of Bjørnesund in the Fiskenæsset region

Abstract

The mapping of the area south of Bjørnesund, begun in 1970, was completed during the summer field season of 1971. During the routine mapping special attention was paid to the gneiss complex. The detailed petrography and chemistry of the gneisses will be the topic of a further paper, but this report gives a brief description of the distinguishing petrographicai characters of the gneiss types. Several types and sub-types of gneisses have been distinguished according to their varying mineral composition, structure, texture and grade of migmatisation. Only those gneiss types and sub-types that occur in units which can be followed for more than 200-500 m are described; xenoliths and small patches of different rock types, however lithologically different, are not.