NEOPROTEROZOIC POSTCOLLISIONAL GRANITOIDS OF THE GLUSHIKHA COMPLEX, YENISEI RANGE

Abstract

The paper reports data on the petrology and geochemistry of granitoids of the Glushikha Complex in the Transangara area of the Yenisei Range and presents U-Pb, Sm-Nd, Rb-Sr, and Ar-Ar isotopic geochemical data on these rocks. Geochemically, the rocks represented generally by subalkaline and normal-alkalinity leucogranites correspond to A-type granites. The U-Pb zircon age of granites of the Glushikha and Strelka complexes corresponds to 730.6 ± 4.6 and 718 ± 9 Ma, respectively. Sm-Nd isotopic data indicate that the parental melts were derived from continental a crustal source, Milch mostly had a Paleoproterozoic age. The leucogranites were most probably produced by the differentiation of subalkaline magmas that had been derived from a continental crustal source in a postcollisional environment. The relations between the Late Precambrian collisional and postcollisional granitoids are discussed with reference to the genesis of the rocks as a consequence of collision of the Central and Western Angara terranes with Siberian continent. The collisional and postcollisional events identified in the area took place prior to the accretion and obduction of the island arcs and ophiolites of the Yenisei belt over the Siberian continent.