Magma Sources and Granitoid Formation Conditions in the Southern Part of the Main Batholith Belt (Kolyma)

The largest Late Jurassic–Early Cretaceous Main (Kolyma) Batholith Belt in Northeast Asia is composed mainly of Bt- and Amp-Bt granites and granodiorites with increased alumina content and potassium alkalinity. The granitoid plutons of the southern part of the belt are similar in structure and composition, but they are characterized by significant variations in Nd isotopic composition, corresponding to parameters of the Meso-Neoproterozoic continental crust. It is assumed that the formation of the granitoids is related to melting of metaterrigenous sediments of the passive margin, which were formed by the erosion of the Siberian paleocontinent in a post-collisional or suprasubduction geodynamic setting.