Stratigraphic Correlation of the Ediacaran Dengying Formation in the Yangtze Gorges Area, South China

The Ediacaran Dengying Formation in the Yangtze Gorges area of South China represents one of the most intensively investigated Ediacaran successions preceding the Cambrian explosion. Traditionally, the Dengying Formation in this area is subdivided into three lithostratigraphic members (Hamajing, Shibantan and Baimatuo members in ascending order). However, the following issues still need further clarification: (1) The lithology and thickness of these members show significant variation over short distances. (2) Different correlation schemes exist for the Miaohe Member (which hosts the Miaohe biota), equating it either with the lower part of the Shibantan Member of the Dengying Formation or with Member IV of the Doushantuo Formation. (3) The correlation of the Dengying Formation across different regions of South China remains unclear. Here we conducted a comparative investigation of the Dengying Formation in the Yangtze Gorges area. Based on lithostratigraphic characteristics, the stratigraphic succession of the Dengying Formation can be categorized into seven types. In different types of sections, five lithological members are developed to varying degrees; in ascending order, these are the Hamajing, Miaohe, Shibantan, Baimatuo and Tianzhushan members. Negative carbon isotope excursions occur at the top of the Hamajing Member, the top of the Shibantan Member, and the top of the Baimatuo Member, respectively. By integrating lithostratigraphy, carbon isotope chemostratigraphy, isotope geochronology, and the occurrence horizon of Shaanxilithes, we establish a stratigraphic correlation among the top of the Shibantan Member of the Dengying Formation in the Yangtze Gorges area, the upper part of the Jiucheng Member of the Dengying Formation in eastern Yunnan Province, and the lower part of the Gaojiashan Member of the Dengying Formation in southern Shaanxi Province. Consequently, this study provides significant insights into regional stratigraphic correlation of the Dengying Formation, and helps define the terminal Ediacaran stage.