Lipid Biomarker Records of Permian Methane Release Events from the Shangsi and Chaotian Sections of South China

Methane was believed to have played a significant role in the continuous warming during the Permian, following the deglaciation of Late Paleozoic Ice Age. This study sampled the well-exposed Shangsi and Chaotian sections in the northeastern region of Yangtze Platform, collecting 113 samples from the Lower Permian Qixia Formation to the lowermost Triassic Feixianguan Formation. Utilizing the biomarker 3-methylhopane of methane-oxidizing bacteria, high-resolution curves of methane activity was established. The results revealed that the 3-methylhopane content in the middle part of the Qixia Formation increased to approximately 0.08 (mean <0.05), with pristane/phytane <1indicating intensive methane aerobic oxidation and accompanying marine hypoxia during middle Permian. Enhancements of 3-methylhopane are also identified from the Maokou Formation to the Dalong Formation, providing important molecular evidence for understanding the microbial responses to climatic changes during Permian and the mass extinction.