Conditions of Formation and Sources of Melts of Early Neoproterozoic Granites in Northern Kuznetsk Alatau

Abstract

Abstract —We present data on the geochronology, geochemistry, and Nd isotope composition of granitoids of the Gremyachikha and North Gremyachikha massifs (Kundusyul pluton) located in the Neoproterozoic metamorphosed island arc calc-alkalic volcanic rocks of the Talanovka–Bogorodka block in northern Kuznetsk Alatau (Martaiga uplift). The granitoids formed 890–880 Ma as a result of the accretion and collision of Neoproterozoic oceanic/island arc complexes with an unknown block formed by continent-marginal metasedimentary strata. The predominance of a metasedimentary source formed during the erosion of the early Precambrian and Neoproterozoic complexes is confirmed by the wide range of the ages of xenogenic zircons in the granitoids (2800 to 930 Ma) and by variations in the εNd values (−7.8 to −1.0) and model Nd age of the granites (2.20–1.64 Ga).