四川华蓥二叠-三叠系界线剖面稳定碳同位素变化特征及其生物地球化学循环成因

对四川华蓥楼房湾剖面稳定碳同位素进行的研究表明，该地区二叠-三叠系界线附近碳同位素变化趋势与全球变化基本一致。早三叠世早期Δ_B平均值高于晚二叠世晚期，指示海水中磷酸盐浓度的增大和初级生产力的繁盛。从晚二叠世末期开始δ¹³C_carb的缓慢降低是由大规模火山作用以及陆地风化作用加强造成的；早三叠世最早期δ¹³C_carb和δ¹³C_org的快速同步降低所代表的全球碳循环变化主要受控于生物集群绝灭的主幕及海平面上升引起的底部缺氧水上涌。总之，二叠-三叠纪之交碳同位素变化是火山作用、海平面变化、海洋和陆地生物集群绝灭以及缺氧水上涌等因素综合作用的结果。

Fluctuations of Stable Carbon Isotopes around the Permian-Triassic Boundary in Huaying of Sichuan,South China:Its Characteristics and Biogeochemical Origin

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.