Molybdenite Re-Os dating of the Tugurige gold deposit, Urad Middle Banner, Inner Mongolia, and its geological significance

Tugurige is a middle-sized gold deposit in Buyant Block, Inner Mongolia. The NW-striking gold-bearing quartz veins penetrate the Late Paleozoic rock mass and Lower Proterozoic Buyant Group. The orebody stably extends along the strike and the dip. The metallic minerals mainly include pyrite, chalcopyrite and galena, whereas the gangue minerals are predominately quartz and calcite. The alteration in the wall rocks includes silicification, sericitization and epidotization. The Re-Os dating of molybdenite samples from gold ore yielded a Re-Os isochron age of (305.6±4.5) Ma with an average of (313.5±4.8) Ma. This implies that the Au and Mo mineralization occurred in Late Carboniferous. The Re content of molybdenites in the Tugurige gold deposit is 42.42×10^-6-307.7×10^-6, suggesting that the ore-forming material was derived mainly from a mixed source of crust and mantle.