Carbon isotope variations and genetic analysis of the Doushantuo Formation of the Edia-caran system in Zhangcunping, Yichang

For the purpose of systematic analysis of the Ediacaran carbon stable isotope curve from the shallow marine facies Doushan-tuo Formation on the northern limbs of the Huangling anticline, the authors chose Zhangcunping and Bailuya sections in Yichang of Hubei Province as the study objects.The results indicate that four remarkable negative (ZN1~ZN4) and three positive carbon isotope anomalies (ZP1~ZP3) exist in the strata.As for negative excursions, the three negative carbon isotope excursions could be compared well with those from the other global typical sections; and the other one could be well recognized in eastern Yangtze Gorges.Further-more, it is held that ZN4 corresponds to DOUNCE event and the typical fourth member of Doushantuo Formation section has not been deposited in the area; ZN1 is a reflection of the global methane leakage incident; ZN2 was caused by regional lowered sea level, which was mich earlier than the Gaskeris glaciation and could be correlated with WANCE event; ZN3 resulted from the regional up-welling, which carried ¹³C depleted organic materials from deep ocean; ZN4 can be explained by the oxidation of organic carbon pool of the Ediacaran Ocean.