Ocellar-Porphyroblastic Granitoids of the Western Part of the Aldan Shield: Geochemistry, Age, and Mechanism of Formation

摘要

The western part of the Aldan Shield occupies the whole area of the Olekma-Vitim Highland. In this area the Charskaya ring structure with a diameter of 260-280 km (1, 2] includes almost all structural-material complexes of the Early Precambrian: from crystalline infra- and supracrustal rocks of Pale-oarchean and Mesoarchean metavolcanogenic-sedimentary formations of greenstone suture zones (troughs) to sedimentary rocks of the Udokan proto-platform trough. Different magmatic and palingene- metasomatic rocks of the Archean and Paleoprotero-zoic are widely abundant in the region (Fig. 1).