Identical carbon isotope trends of carbonate and organic carbon and their environmental significance from the Changhsingian (end-Permian), Meishan, South China  

作　　者：LI Yucheng LIU Wenhui WANG Wanchun ZHENG Jianjing 

机构地区：[1]Laboratory of Environmental Biogeochemlstry, School of Resources and Environmental Engeneering, Anhui University, Hefei 230039, China [2]Wuxi Institute of Petroleum Geology, SINOPEC, Wuxi 214151, China [3]Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China

出　　处：《Chinese Journal Of Geochemistry》2011年第4期496-506,共11页中国地球化学学报

基　　金：supported jointly by the National Natural Science Foundation of China (40972092);the Special Program for National Science and Technology (2008ZX05005-01-08);the United Foundation of NSFC and China's Petroleum Chemical Industry (40739902)

摘　　要：High resolution carbon isotope analyses of carbonate and organic carbon from Meishan, South China showed that the variation of δ13Ccarb is marked by three large positive excursions during the Changhsingian (end-Permian). Carbon isotope stratigraphy during this stage shows three cyclic intervals in δ13Ccarb, with two cycles corresponding to the lower (Paleofusulinid minima Zone) and one corresponding to the upper Changhsingian (P. sinensis Zone). The large positive δ13Ccarb excursions indicate episodes of enhanced burial of isotopically light or-ganic carbon, presumably in response to deep-water anoxia episodically extending into shallow water with the rise of sea level. The organic carbon during the Changhsingian is distinguished into two groups, and the δ13Corg of each group parallels (separately) the more detailed profile of δ13Ccarb, strongly showing that the values of fractionation Δ13Ccab-org remain relatively constant, with only two intervals with anomaly. The enhanced fractionation Δ13Ccab-org with large negative δ13Corg excursions apparently indicates significant inputs from sulfide-oxidizing bacteria and green sulfur bacteria, notably at bed 24 just predating mass extinction. Our evidence appears to support that the ex-tended euxinic water is possible for the main pulse of mass extinction at the end-Permian.High resolution carbon isotope analyses of carbonate and organic carbon from Meishan, South China showed that the variation of δ13Ccab is marked by three large positive excursions during the Changhsingian （end-Permian）. Carbon isotope stratigraphy during this stage shows three cyclic intervals in δ13Ccarb, with tWO cycles corresponding to the lower （Paleofusulinid minima Zone） and one corresponding to the upper Changhsingian （P. sinensis Zone）. The large positive δ13Ccarb excursions indicate episodes of enhanced burial of isotopically light or- ganic carbon, presumably in response to deep-water anoxia episodically extending into shallow water with the rise of sea level. The organic carbon during the Changhsingian is distinguished into two groups, and the δ13Corg of each group parallels （separately） the more detailed profile of δ13Ccarb, strongly showing that the values of fractionation Δ13fcab_org remain relatively constant, with only two intervals with anomaly. The enhanced fractionation A13fcab.org with large negative δ13Corg excursions apparently indicates significant inputs from sulfide-oxidizing bacteria and green sulfur bacteria, notably at bed 24 just predating mas extinction. Our evidence appears to support that the extended euxinic water is possible for the main pulse of mass extinction at the end-Permian.

关 键 词：有机碳同位素 二叠纪末 碳酸盐岩 中国南方 环境意义 硫化物氧化细菌 同位素地层学 同位素分析 

分 类 号：P532[天文地球—古生物学与地层学] P534.46[天文地球—地质学]