A preliminary report on the geology of the Koli area

Abstract

The bedrock of the Koli area originates from two separate orogenic cycles. Of these only the younger one, the Svecokarelian orogenic cycle, is dealt with in detail in this account. The sedimentary rock units of this cycle were deposited at the edges of the karelian geosynclinal basin. The origin of the sedimentary formations and that of the basic magmatism of the area is closely associated with the development of this basin which was characterized by the subsidence of its bottom, and by sudden releases of the thus generated strain field.