关键词: 稳定碳同位素, 二叠-三叠系界线, 生物集群灭绝, 碳循环, 四川华蓥

Abstract: Detailed researches on the stable carbon isotopes at the Loufangwan Section, Huaying, Sichuan Province show the stable carbon isotopes has the similarities with many other Permian-Triassic records around the world. A larger mean value of Δ_B in earliest Triassic than that in latest Permian indicates increasing concentration of phosphate and bloom of primary producers in the ocean. Large volcanic eruption and enhanced weathering that began in the end of Permian were possible triggers for a slow decrease in δ¹³C_carb. Synchronously, quick decreases in δ¹³C_carb and δ¹³C_org in the earliest Triassic, indicating a global carbon cycle change, might be due to the main episode of the mass extinction and upwelling of anoxic deep-water masses during sea level rise. Therefore, the carbon isotopes profile around the Permian-Triassic boundary may reflect combined results of volcanic activity, sea level change, mass extinction of marine and land biomass decrease and anoxic water upwelling.

Key words: stable carbon isotope, Permian-Triassic boundary, mass extinction, biogeochemical cycle, Huaying, Sichuan Province