Sulfur-lead isotopic composition of the Wulagen Pb-Zn deposit in the northwestern margin of the Tarim Basin, Wuqia area, Xinjiang and its geological implications

Located in Wuqia area of western Xinjiang, the Wulagen lead-zinc deposit is hosted by Mesozoic-Cenozoic strata of Kashi depression in the northwestern margin of the Tarim Basin. Recent studies and prospecting have confirmed the favorable ore-forming conditions of this ore deposit, and the mineral potential should be very large. However, its genesis remains controversial for a long time. In this paper, S-Pb isotopic compositions of sulfides from ore bodies in the ore deposit were systematically determined so as to discuss the source of ore-forming material and the genesis or the ore deposit. The sulfur isotopic compositions δ34S in ore bodies are in a wide range of -26.09-+15.0‰. The sulfur-rich characteristics of two-terminal element indicated that the sulfur might have been derived from the marine sulfate thermal chemical reduction. The lead isotopic ratios are 206Pb/204Pb=17.771～18.6413, 207Pb/204Pb=15.402～15.6454, and 208Pb/204Pb=37.92～38.7507, respectively, varying very narrowly and plotted near the orogenic belt evolution curve. It can be inferred that the ore-forming metals were probably derived from the the old stratum. These results and previous data Wulagen lead-zinc deposit was one of the sediment-Hosted lead-zinc deposits, related to the thrust-nappe setting of South Tianshan-West Kunlun regional orogenic belt, large-scale migration of basin fluids and the reducing conditions from oil and gas.