THE VENDIAN ACCRETIONARY EVENT IN THE SOUTHWESTERN MARGIN OF THE SIBERIAN CRATON

Abstract

The present-day southwestern margin of the Siberian Craton is represented by its Early Precambrian inliers (Angara–Kan and Sayan) and Mesoproterozoic-Neoproterozoic marginal continental region that includes the Yenisei Range and Sayan areas. The Early Precambrian evolution of structures of the Siberian Craton culminated with formation of the Early Proterozoic Angara continental-margin foldbelt, intense intrusion of granitoids (1.87–1.84 Ga ago), and its general consolidation. Mesoproterozoic–Neoproterozoic fold–thrust complexes in the trans-Angara part of the Yenisei Range and largely riftogenic complexes of the Sayan region demonstrate all features typical of the ensialic marginal continental and intracontinenal structures. Precambrian blocks and terranes in folded structures of the Central Asian foldbelt were united into the Sayan–Yenisei accretionary belt. The belt includes Early and Late Proterozoic island-arc and oceanic terranes (Central, Idar, and Shumikha–Kirel terranes in the Kan block; Arzybei, Isakovka, and Predivinsk) or terranes with substantially metasedimentary sections (Derba) and fragments of oceanic and island-arc structures (Kuvai Group) overlain by Vendian–Cambrian strata in the Man Trough.