Relationship between magmatic, metamorphic and hydrothermal processes within the Baikal-Muya terrane (Eastern Siberia): constraints from a high-precision geochronological study of the Kedrovsky granitoid massif

Abstract

High-precision dating of granitoids is significant for identification the ages of the main stages of crust formation in various blocks of the continental crust. In this work, we dating the Kedrovskiy diorite-granodiorite massif localized within the South Muya block of the Baikal-Muya accretion terrane (BMT) (Eastern Siberia) among the Neoproterozoic gabbroids of the Kedrovskiy complex and metasedimentary rocks of the Kedrovskaya Formation. The results of U-Pb (ID TIMS) and 39Ar-40Ar geochronological studies of the Kedrovskiy massif are discussed. The formation of the massif (781 3 Ma) occurred at an early stage formation of the Proterozoic continental crust of BMT during accretion of Baikalids with the Siberian craton. A later thermal event (626 11 Ma) of the Ediacaran stage evolution BMT is reflected in the formation of of biotite-quartz-feldspar veins that cut through the granitoids of the Kedrovka massif. The obtained geochronological data show that the gold mineralization of the Kedrovskiy deposit (273 4 Ma) was not generated by the Kedrovskiy massif granitoids.