Anthophyllite-cordierite gneisses are found together with supracrustal rocks in an elevated "block" of supposed Precambrian age in the eastern part of the Haugesund Peninsula. Their formation seems to be due to regional metamorphism of sediments and/or volcanics. Metamorphic differentiation and partly internal metasomatism have probably taken place, mostly during the conditions of almandine-amphibolite facies. Later retrogressive metamorphism has affectcd most of the rocks. The gneisses and their accompanying rocks are partly analogous both to rocks of the Orijärvi Region, Finnland, and to rocks from Kongsberg-Bamble. Southern Norway. It is suggested that the rocks may represent a western outcrop of the Kongsberg-Bamble rocks. But definitc evidence cannot yet be given.
Anthophyllite-cordierite-gneisses in the basal rock complex of the Haugesund peninsula, western Norway.