Sulfur and carbon isotopic variations in Neoproterozoic sedimentary rocks from southern China *

A new set of δ34Ssulfide δ34Ssulfate and δ13Ccarbonate values has been reported from Neoproterozoic sedimentary rocks in southern China. The interglacial blackshales of the Datangpo Fm. display higher δ34Ssulfied values with > + 20‰. average, but the postglacial black shales from the Doushantuo Fm. show negative δ34Ccarbonate values. However, the Jinjiadong Fm., the same post-glaciation 3 as the Doushantuo Fm., has positive δ34Ssulfide values, implying that the δ34S value of sedimentary sulfides wouldbe controlled by lithofacies and paleogeographic environments. The δ34Ssulfate values relative to δ13Ccarbonate were obtained by extraction of trace sulfate from the successive carbonate sequences in the Yangtze Gorges sections. A preliminary interpretation suggests that the oceanic environment may fluctuate dramatically at the post-glacial Doushantuo stage and, then, recover its stability at the Dengying stage on the basis of the high resolution δ34S and δ13C corves of seawater.