[B-CG07] Decoding the history of Earth: From Hadean to the present

[BCG07-08] High-temperature combustion event spanning the Guadalupian−Lopingian boundary terminated by soil erosion

*Kunio Kaiho¹, Stephen E. Grasby², Zhong-Qiang Chen³ (1.Tohoku University, 2.Geological Survey of Canada, 3.China University of Geosciences (Wuhan))

Keywords:combustion event, mass extinction, ocean redox, Permian, soil erosion, volcanism

A major bio-crisis in the Guadalupian−Lopingian transition (Capitanian−Wuchiapingian, middle−late Permian), possibly driven by the volatile eruption of the Emeishan large igneous province (LIP), was marked by the first-order collapse of global metazoan reefs and decline of fusulinid foraminifera, but with only minor impacts on other marine invertebrates (brachiopod, crustacea, other foraminifera). To assess the exact cause of this event, we conducted geochemical analyses of the shallow marine strata at the global stratotype section and point of the Guadalupian−Lopingian (G−L) boundary (GLB) in Laibin, South China, which corresponds to the last step of the Capitanian bio-crises during Emeishan volcanism. Here, we detect evidence for high temperature combustion of organic matter in air spanning the GLB (indicated by enriched coronene) that was terminated by a soil erosion event accompanied with terrestrial vegetation collapse at the mass extinction level (evidenced by enriched dibenzofuran) and a carbon isotope perturbation (a 2.5−3.5‰ negative shift of δ¹³C_carb). Molybdenum data indicates oxic seawater during the combustion event, likely reflecting regression. These findings imply that large volatile volcanic eruptions of the Emeishan LIP may have caused these environmental extreme events and mass extinctions, and that relatively lower magnitude of volcanism related to Emeishan LIP may have led to impacts on terrestrial−nearshore ecosystems.