Astronomical time scale for the Doushantuo Formation ofEdiacaran in South China: Implications for the duration of the negative δ13C excursion

Reconstructing the high-resolution astrochronology framework for the Ediacaran is critical to fully understand the evolution of the sedimentary environment and the carbon cycle in South China. The Ediacaran was perhaps one of the most important intervals in the Earth's sedimentary environment and biological evolution history, which witnessed the carbon isotope perturbation frequently, the emergence and evolution of metazoans, and the extreme climate change. There are many controversies for the characteristics and origin of these geological, biological and extreme climate events due to the lack of continuous and high-resolution astronomical time scale in the Ediacaran. We here propose to study the systematic cyclostratigraphic analysis of the Doushantuo Formation based on the Jiulongwan section in South China, and then use the long-eccentricity (405-kyr) for astronomical tuning to establish continuous and high-resolution astrochronologic framework, which would provide chronological constraints on carbon isotope negative  excursions, biological evolution and the extreme climate change for the Ediacaran. In order to reveal the inner correlation of the onset age, sequence of these major geological events as well as biological evolution in the Doushantuo Formation on the Ediacaran. Moreover, we also try to discuss the astronomical orbits-forcing factor that may lead to the occurrence and evolution of these major geological events, which would provide scientific evidence for studying the global climate change in the future.