The Sulfur Isotopic Characteristics of Evaporites in the Yarkand Basin of Xinjiang Province in the Paleocene and Its Paleoenvironmental Evolution

The Yarkand Basin, located in the southwest of Tarim is a northeastern part eastern Paratethys ocean Paleocene, and significant amount evaporites, with gypsum, anhydrite, halite as main types, were developed this area. These evaporites record sedimentary environment at that time. A study was conducted on sulfur isotopic composition gypsum Paleocene Basin to explore origin interpret environment. experimentally measured isotope δ34SCDT values 187 samples ranged from 6.69‰ 25.92‰ an average value 18.64‰. overall trend curve consistent global seawater curve, which shows decreasing trend. In early middle four stages increase, indicating during time mainly influenced by bacterial reduction relatively open environment, while late period trend, suggesting may be primarily terrigenous freshwater. addition, has characteristics northwest southeast basin, indicate also related paleotopography distance estuary, resulting differences environments. original should range 18‰–20‰, supplement paleoseawater great significance for reconstruction marine transgressive–regressive cycle period.