A Study Group under the leadership of W. Wimmenauer was set up to look at the nomenclature of migmatites and related rocks. In addition to that small group, a number of worldwide specialists were consulted on their views on the more important terms being considered. Their answers were greatly appreciated and provided valuable contributions to the deliberations. This paper presents the definitions together with some notes explaining the reasoning.
The autochthonous basement in Norway shows progressively greater plastic deformation towards the NW, but the in situ Caledonian metamorphism has surpassed low - grade conditions only in the western part of the country. The nappes, however, represent a telescoped sequence. They provide a broader sample of the total orogenic belt and contain extensive zones of low - grade and medium - grade rocks of the intermediate pressure series. Lack of adequate information on zones of incipient metamorphism, the true nature of isograd boundaries, and especially the age of many mineral assemblages, make compilation of a metamorphic map of the Norwegian Caledonides very difficult at the present stage.
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