REE geochemistry of ore zones in the Archean auriferous schist belts of the eastern Dharwar craton, south India

摘要

The eastern Dharwar Craton of southern India includes at least three a??2700Ma supracrustal belts (schist belts) which have mesothermal, quartz-carbonate vein gold mineralization emplaced within the sheared metabasalts. In the Hutti and the Kolar schist belts, the host rocks are amphibolites and the ore veins have been anked by only a thin zone of biotitic alteration; in the Ramagiri belt, however, the host rocks to the veins have been a ected by more extensive but lower temperature alteration by uids. The rare earth element (REE) geochemistry of the host metabasalts, alteration zones, ore veins and the bulk sulfides separated from the ore veins and the alteration zones suggest thatthe REE chemistry of the immediate host rocks has been modified by uids which added LREE,