New material of microfossils from the Ediacaran Doushantuo Formation in the Zhangcunping area, Yichang, Hubei Province and its zircon SHRIMP U-Pb age

Abstract

The Zhangcunping area is located at the north limb of the Huangling anticline in Yichang, Hubei Province. Here, the sedimentary succession of the Ediacaran Doushantuo Formation is similar with that in the Weng’an area, Guizhou Province. A large number of new microfossils (mainly acanthoacritarchs) from the Doushantuo Formation in this area are reported in this paper. The fossil assemblage shows similarity as the phosphatized biota of the Doushantuo Formation at Weng’an, Guizhou Province and the silicified biota of the Doushantuo Formation at the Yangtze Gorges, which suggests that the Zhangcunping area is a key for correlation of the Doushantuo Formation between the Weng’an area, Guizhou Province and the Yangtze Gorges. Besides, a new zircon SHRIMP U-Pb age (614.0±7.6 Ma) is first obtained from a horizon underneath the exposed surface in the middle of the Doushantuo Formation in the Zhangcunping area. This age not only provides a new datum for subdivision of the Ediacaran Doushantuo Formation, but also indicates that the age of the exposed surface in the middle of the Doushantuo Formation in the Yangtze Platform should be posterior to 614.0±7.6 Ma. Due to the horizon of the Weng’an biota situated above the exposed surface, the age of the Weng’an biota should be posterior to 614.0±7.6 Ma as well.