Sulfur Isotopic Composition of Gypsum from Paleocene, Northwest China: Implications for the Evolution of Eastern Paratethys Seawater

The sulfate isotope record of marine sedimentary through time has been used successfully to determine global variations in the composition seawater sulfate. sulfur reflect changes cycle and are also closely related atmospheric oxygen cycles. However, data for Paleocene very sparse stratigraphic evolution is poorly constrained due small number samples analyzed. Yarkand Basin, as a northeastern part eastern Paratethys ocean with trumpet-shaped bay, which suite evaporitic sequences named Aertashen Formation was continuously developed principally composed massive gypsum interbedded fragmental rocks. values isotopic from 12.2‰ 20.6‰ (δ34 SCDT or δ34 SVCDT) mean 17.7‰ 97 basin. Three gradually increasing trends curves that enrichment S occurred sulfate, indicate oxidation sulfide. These may hint at least three events bacterial reduction sulfide Paleocene, oxygen-enriched biological might exist this epoch. about 15.0‰ 20.6‰, averaged 17.9‰ Paleocene. Combined previous seawater, final range be 21.0‰, 17.9‰–18.3‰ average so reconstructed supplemented.