Major geological events in the late Guadalupian and carbon–strontium isotope responses in the Yangtze platform, South China

Two sections of marine carbonate strata, Podu and Lengshuixi, from the Yangtze platform, South China, are investigated in terms of major geological events and carbon–strontium isotope responses. The results show a large-scale regression and a Large Igneous Province (LIP) event occurred in succession in the short interval of the late Guadalupian, inducing a biodiversity crisis. The regression event, marked by an increase in the 87Sr/86Sr ratio, is observed in the Jinogondolella postserrata Zone. It contributed significantly to the reduction in species habitat, leading to notable losses within the shallow-water species assemblage. A subsequent LIP event occurred after the appearance of Jinogondolella altudaensis, releasing CO2 and numerous other deleterious gases that further amplified the crisis in shallow-water to deep-sea environments. The corresponding decline in Sr and C isotopes could have been a response to the basaltic eruption (relative increase from mantle-derived Sr) and release of 12C-enriched CO2. During the process of creation of the LIP, the decline in δ13Ccarb was mainly associated with 12C-enriched CO2 release from organic matter in sedimentary strata, and high-temperature isotope fractionation during the volcanic eruption stage (exceeding 1200 °C). This study could further provide valuable clues regarding the development process of the major geological events and the causes of the biodiversity crisis.