GEOCHEMISTRY OF GRANATE-BIOTITE AND BIOTI TE-PLAGIOCLASE GNEISSES OF THE OLKHON ICELAND AND OLKHON AREA (WEST BAIKAL REGION)

The granate-biotite and biotite-plagioclase gneisses of the Ol'khon ar ea are reported as metaterrigenous graywacke type rocks in concern wit h their geochemical peculiarities and geological position. The reveale d geochemical evolutionary trends of the Ol'khon and Angin series of t he Baikal metamorphic complex is in correlation with the change of che mical composition of basic volcanic rocks up to the tholeiitic and alk aline-basaltic types. This tendency is reflecting the change of geodyn amical conditions of sedimentation at the time of protolite formation.