FRAGMENTS OF OCEANIC ISLANDS IN THE KURAI AND KATUN' ACCRETIONARY WEDGES OF GORNY ALTAI

Abstract

The paper presents new data on the structure and composition of the Vendian-Early Cambrian oceanic crust of the Paleo-Asian ocean, which has been fragmentally preserved in Early Cambrian accretionary prisms of Gorny Altai. Mid-oceanic ridge and oceanic island basalts are recognized on the basis of their geochemical characteristics and the composition and geological relationships of volcanogenic and sedimentary units. Our data indicate that hot-spot and mid-ocean ridge volcanism was active in the early stages of the Paleo-Asian oceanic evolution, from Vendian to Early Cambrian. The study of paleo-oceanic islands incorporated in accretionary-collisional belts is important for the reconstruction of ancient oceans and understanding of endogenic processes that resulted in the formation of the oceanic lithosphere. Vendian-Cambrian, oceanic crust, Paleo-Asian ocean, MORB, OIB