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对煤山P/Tr界线地层进行了分子及碳同位素地球化学研究,给出了长兴组至殷坑组底部的异戊二烯烷烃分子及有机碳同位素地球化学剖面,揭示了事件界线层附近存在着δ13Ckero与δ13Cmole的强烈变化及姥鲛烷相对富集的异常特征.对界线附近姥鲛烷相对富集的成因提出一可能机制:由相对富集姥鲛烷的海洋动物脂类及其代谢产物在某些特殊条件下(如动物集群快速绝灭及/或缺氧条件发育)得到保存并在有利相带聚集而形成.对地质历史时期其它重要海洋缺氧沉积(与晚奥陶纪、泥盆纪末、早侏罗世及晚白垩世重要生物绝灭事件相关)富集异戊二烯烷烃及高Pr/Ph值的发现在一定程度上支持了上述关于P/Tr界线姥鲛烷富集机理的解释.煤山剖面由24~26层δ13Cmole,δ13Ckero及δ13Ccarb的一致性强烈负漂移,指示了二叠纪末大气-海洋系统碳源在低幅快速变化的过程中存在一个陡然而强烈的变化阶段;姥鲛烷相对富集与δ13Cmole及δ13Ckero负偏的耦合,可能指示了甲烷水合物释放和海洋缺氧过程在二叠纪末生物大绝灭过程中的重要作用.
The molecular and carbon isotopic geochemistry of P / Tr boundary strata in Meishan has been studied. The isoprenoid molecular and organic carbon isotopic geochemical profiles at the bottom of Changxing Formation to the Yinkeng Formation are given, and the existence of the vicinity of the event boundary layer The strong changes of δ13Ckero and δ13Cmole and the anomalous characteristics of relative enrichment of pristane.A possible mechanism of the relative enrichment of pristane near the boundary is proposed.From the relative enrichment of pristane marine lipids and their metabolites Under some special conditions (such as rapid extinction of animal assemblages and / or development of hypoxic conditions), they are preserved and accumulated in the favorable facies belt. For other important marine hypoxic sediments in the geological history (compared with late Ordovician, mud The discovery of enrichment of isoprenoid and high Pr / Ph values at the end of the basin, the Early Jurassic, and the Late Cretaceous correlated with the above-mentioned findings regarding the P / Tr boundary basaltic anemia Set mechanism.The strong negative drift of the consistency of δ13Cmole, δ13Ckero and δ13Ccarb from 24 to 26 layers in the Meishan section indicates that there is a steep and sudden change in the carbon source of the Permian end-atmosphere marine system during the low-amplitude rapid change Strong phase change; pristane coupled to opposite δ13Cmole δ13Ckero negative bias and enrichment, may indicate the release of methane hydrate at the end of the process and anoxic marine Permian extinction important role in biological processes.