新疆吐鲁番盆地陆相白垩纪与古近纪界线的环境指标  

Environmental Proxies from the Terrestrial Cretaceous-Paleogene Boundary in the Turpan Basin,Xinjiang

作　　者：续晓璟[1] 昝立宏[1] 程捷[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室

出　　处：《现代地质》2006年第3期423-428,共6页Geoscience

基　　金：中国核工业总公司地质局项目(2-8-01-04)

摘　　要：通过对新疆吐鲁番盆地白垩纪和古近纪陆相地层的氧化物、碳酸钙、有机碳含量分析以及有机碳稳定同位素的测试,并通过w(Fe3+)/w(Fe2+)比值指示的古温度研究,探讨了该地区白垩系—古近系界线的特征以及古气候特点。研究表明在白垩系/古近系界线附近各项环境指标发生了明显的变化。在白垩纪末期,有机碳同位素1δ3Corg明显偏正,A l2O3、Fe2O3含量降低;而进入古新世,1δ3Corg明显偏负,A l2O3、Fe2O3含量升高。对w(Fe3+)/w(Fe2+)比值指示的古温度计算表明,在白垩纪末期大气温度比较低,而进入古新世气温回升,这与进入古新世有机碳稳定同位素明显偏负的特征一致。On the basis of the oxide, calcium carbonate and organic carbon contents, and organic carbon stable isotope of the continental strata in the Turpan Basin, Xinjiang, together with the ratio of Fe^3＋/Fe^2＋, the Cretaceous/Paleogene boundary and paleoclimate during this period have been studied. Our studies have revealed that an apparent oscillation of all environmental proxies occurred near the boundary. At the terminal Cretaceous, δ^13Corg increased significantly, organic carbon, calcium carbonate, SiO2 and Al2O3 contents decreased, while at the beginning of Paleocene, the increasing of SiO2 and Al2O3 contents was accompanied by the decreasing of δ^13Corg. These changes actually reflected a cool event in the latest Cretaceous. Study of ratio of Fe^3＋/Fe^2＋ further indicated that the temperature was low in the latest Cretaceous, which is consistent with the result derived from the organic carbon isotope.

关 键 词：白垩系/古近系 界线 有机碳 同位素 氧化物 吐鲁番盆地 新疆 

分 类 号：P534[天文地球—古生物学与地层学] P539[天文地球—地质学]