The Revision of the Meso-Neoproterozoic Stratigraphic Chart in China

The study of the “Sinian System” in China spans over a century and has undergone several major revisions and modifications. Prior to the reform and opening-up policy, research remained at an initial, exploratory stage. Following the reform and opening-up, it entered a phase of rapid and refined investigation. Throughout this research process, the chronostratigraphic subdivision of the Meso-Neoproterozoic in China has increasingly aligned with revisions to the international geologic timescale. Entering the 21st century, systematic progress has been made in the study of lithostratigraphy, chemostratigraphy, and chronostratigraphy of the Chinese Meso-Neoproterozoic, providing reliable data and candidate stratotypes for further optimizing the chronostratigraphic framework of the Chinese Meso-Neoproterozoic. An increasing number of “Sinian System” successions have been repositioned. Based on the integration of international and domestic research over the past two decades, this paper draws the following conclusions and recommendations: (1) Subdivide the “Unnamed System” into the Xishan System (1.4–1.2 Ga) and the Yuxi System (1.2–1.0 Ga). The Xishan System takes the Xiamaling, Luotuoling, and Jing'eryu formations as its stratotype sections. The Yuxi System takes the Laowushan Formation and the lower part of the Kunyang Group as its stratotype sections. (2) Subdivide the former “Qingbaikou System” into the Qingbaikou System (1.0–0.82 Ga) and the Yangtze System (820–720 Ma). The Qingbaikou System takes the upper part of the Kunyang Group and the Bajie Group as its stratotype sections, while the Yangtze System takes the Banxi Group, Xiajiang Group, etc. as its stratotype sections. (3) The revised “Sinian System” comprises, in ascending order: Changcheng System (1.8–1.6 Ga), Jixian System (1.6–1.4 Ga), Xishan System (1.4–1.2 Ga), Yuxi System (1.2–1.0 Ga), Qingbaikou System (1.0–0.82 Ga), Yangtze System (820–720 Ma), Nanhua System (720–635 Ma), and Sinian System (635–538 Ma).