Ytre Rendal og Stor-Elvdal. Beskrivelse til de geologiske rektangel- kart.

Abstract

The solid rocks of the map sheet Ytre Rendal and Stor-Elvdal have been mapped by per Holmsen and Chr. Oftedahl. The rock types belong to the following groups: Precambrian, essentially granitic rocks. Sparagmite Group, comprising a sequence of sedimentary formations. The term sparagmite was applied to a feldspar-rich sandstone by J. Esmark (1829). This rock type, which has been classified as arkose, is characteristic for the group. The age is eocambrian, a term used by W.C. Brøgger, describing the group as being deposited just before fossiliferous lower Cambrian. Cambrian and Ordovician formations very subordinate in quantity but of stratigraphic importance. Thrust crystalline rocks of various kinds. One group, comprising anorthosite, pyroxenite, gabbro and dolerite, may be classified as igneous. Another group, comprising augengneiss and granitic gneiss, is transformed by metasomatism. A third group, comprising green schists and quartz-mica schists, are true sediments. It is possible to distinguish between a number of tectonic units within the described area, depending on difference in rock types or difference in degree of metamorphism.