Geochemistry and Re–Os geochronology of the organic-rich sedimentary rocks in the Jingtieshan Fe–Cu deposit, North Qilian Mountains, NW China

The Jingtieshan Group in the North Qilian Mountains, NW China, is dominantly composed of banded iron formations (BIFs), copper deposits and organic-rich sedimentary rocks (ORS, carbonaceous phyllite). X-ray diffraction analysis of the ORS shows the mineral assemblage to be quartz + clay minerals. The total organic carbon contents show a range of 0.44–1.72%. Here we present the results of the geochemistry and Re–Os geochronology of the ORS from...