EVOLUTION OF THE PALEOZOIC GORNY ALTAI ST RUCTURE - CORRELATION OF PALEOMAGNETIC AND GEOLOGICAL DATA

Correlation of paleomagnetic and geological data on the terrains of th e Caledonian accretion-collision structure of the western part of the Altai-Sayan folding region (Gorny Altai) has been carried out. Vendian -Early Cambrian oceanic uplifts, Late Riphean(?)-Early Cambrian oceani c ophiolites occurring in the Early Cambrian accretion prism, and form ations of the Vendian primitive island are and Cambrian backarc basin have been studied. The laboratory investigations permitted us to disti nguish three magnetization components of different age: A prefolding ( close to the primary magnetization), B-cofolding (related to the very early folding stage), and C-postfolding. Comparison of the paleomagnet ic poles calculated along these directions with the trajectory of the apparent wobbling of the paleomagnetic pole (AWPP) of the Siberian Pla tform as well as the geodynamic and structural peculiar features of th e studied region and new geochronological data suggest that component A (Early Cambrian) corresponds to the period of the collision of the B iya-Katun' and Baratala oceanic elevations with the Uimen-Lebed' primi tive island arc; component B (Late Cambrian-Early Ordovician) is a met achron magnetization formed as a result of the attachment of the Kuzne tsk-Altai island are to the Siberian continent; component C resulted f rom the great shift-thrusted dislocations of the region in the end of the Paleozoic. Since the beginning of the Cambrian the studied fragmen ts of the structure of Gorny Altai were the elements of the Kuznetsk-A ltai island-are system, which was located within 14-36 degrees S and c ontoured the northeastern (in the ancient coordinates) margin of the S iberian continent. By the beginning of the Ordovician, the island-are system was attached to the continent. For this period, the system move d northward to 7-18 degrees S, having turned through 30-40 degrees cou nterclockwise.