Isotope Geochemistry of the Shenshuitan Gold Deposit within the Wulonggou Gold Field in the Eastern Kunlun Orogen, Northwest China: Implications for Metallogeny

The Shenshuitan gold deposit is located within the Eastern Kunlun Orogen in northwest China. The gold mineralization here occurs primarily within the ductile fault XI. The sulfide mineral assemblage is dominated by pyrite and arsenopyrite, with minor pyrrhotite, chalcopyrite, galena, and sphalerite. Host rocks predominantly consist of Ordovician silicic slate and late Silurian granites, and their alterations include silicification and sericitization. The measured delta D and delta O-18 values of quartz and sericite range from -113.9 parts per thousand to -93.1 parts per thousand and from 4.6 parts per thousand to 12.0 parts per thousand, respectively. Bulk and in situ delta S-34 values of sulfides range from -7.3 parts per thousand to +9.6 parts per thousand and from -3.92 parts per thousand to 11.04 parts per thousand, respectively. Lead isotope compositions of sulfides show Pb-206/Pb-204 ratios from 18.071 to 19.341, Pb-207/Pb-204 ratios from 15.530 to 15.67, and Pb-208/Pb-204 ratios from 37.908 to 38.702. Collectively, the isotope (H, O, S, and Pb) geochemistry suggests that the ore-forming fluids were of a metamorphic origin mixed with meteoric water and that the sulfur and lead were sourced from a mixture of host rocks and original ore-forming metamorphic fluids. Lastly, this deposit can be classified as an orogenic gold deposit associated with the final collision between the Bayan Har-Songpanganzi Terrane and the Eastern Kunlun Orogen during the Later Triassic.