江西东岭剖面P-T界线碳同位素变化与沉积物输入的关系  

The Relationship between Carbon Isotopic Changes and the Sediments Supply at the P-T Boundary in Dongling Section,Jiangxi Province

作　　者：白玛曲宗 韦恒叶[1,2] 江增光[2] 邱振[3] BAI MaQuZong;WEI HengYe;JIANG ZengGuang;QIU Zhen(Laboratory Atmospheric Environment,Key Laboratory of Nuclear Resources and Environment(Ministry of Education),East China University of Technology,Nanchang 330013,China;School of Earth Science,East China University of Technology,Nanchang 330013,China;Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China)

机构地区：[1]东华理工大学核资源与环境教育部重点实验室大气环境实验室,南昌330013 [2]东华理工大学地球科学学院,南昌330013 [3]中国石油勘探开发研究院,北京100083

出　　处：《沉积学报》2018年第2期267-279,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金(41302021);东华理工大学核资源与环境教育部重点实验室大气环境实验室开放基金(AE1604)~~

摘　　要：二叠纪末期发生了显生宙以来规模最大的生物灭绝事件,利用江西修水东岭剖面二叠—三叠系界线的碳同位素、主量元素及微量元素分别研究全球碳循环的变化及其相对应的物源的变化进而分析环境变化与生物灭绝的关系。研究结果表明,东岭剖面二叠—三叠系界线存在阶梯式碳同位素负偏,第一阶段阶梯式负偏幅度为2‰,第二阶段阶梯式负偏幅度为2.5‰,总的负偏幅度高达4.5‰。在阶段阶梯式碳同位素负偏过程,碳酸盐岩中的硅酸盐组分物源由基性火成岩转变为岛弧性质的酸性火成岩。后者可能与我国华南周围岛弧火山喷发有关。这些碳同位素负偏在时间上与物源的转变及火山灰层基本一致,推测其与我国华南岛弧火山及西伯利亚大火成岩省喷发有关。大规模火山作用喷出或诱发出的二氧化碳及甲烷温室气体有可能是造成二叠—三叠系阶梯式碳同位素负偏的主要原因。火山喷发造成的环境恶化如全球变暖、海洋缺氧、海洋酸化、植被破坏形成的大量沉积物输入海洋致使生物生存压力增大,从而造成二叠末期生物的大灭绝。The largest mass extinction event in the Phanerozoic took place at the end of Permian.The cause of this biological crisis is still remaining controversial.This work uses the carbon isotope,major and minor elements across the Permian-Triassic boundary at the Dongling section in the Xiushui city of the Jiangxi Province to study the relationship between the global carbon cycle perturbation and consistent provenance changes and the mass extinction.The results show that the carbonate carbon isotope profile displays stepwise negative excursion.The magnitudes of first and secondary stepwise are 2‰and 2.5‰,respectively,with a total magnitude of 4.5‰.In the process of stepwise negative excursion of carbon isotope,the provenance of silicate composition in the carbonate rock changes from mafic igneous rocks to island arc intermediate-acid igneous rocks.The later probably concern with the volcanic eruption of Southern China Island.According to negative excursion of carbon isotope has the same time with the change of provenance and ash layer,conjecture it may relate to South China island arc volcanism and volcanism eruption of Siberian large igneous provinces.Large-scale volcanism eruption released or triggered carbon dioxides and methane.These greenhouse gases and the global regression probably are the main causes for this stepwise carbon isotopic excursion across the Permian-Triassic boundary.The deteriorated environments resulted from the volcanism,e.g.,global warming,marine anoxia,marine acidification,large sediment influx resulted from vegetation deterioration,lead to the increased pressure of organism existence and thus the mass extinction.

关 键 词：碳同位素 二叠-三叠系界线 物源 生物灭绝 东岭剖面 

分 类 号：P597[天文地球—地球化学] P512.2[天文地球—地质学]