湘西及邻区晚震旦世—早二叠世黑色岩系的沉积环境——Ce、Nd同位素制约  

Depositional Environments of the Late Sinian—Early Permian Black Rock Series——Ce,Nd Isotopic Constraint

作　　者：李志昌[1] 陈孝红[1] 刘文贵[1] 

机构地区：[1]宜昌地质矿产研究所

出　　处：《地球学报（中国地质科学院院报）》1999年第4期368-377,共10页Acta Geoscientia Sinica

基　　金：<湖北黄陵地区陆壳演化的Ce 同位素示踪>项目;国土资源部同位素地质研究开放实验室及部行业基金!( 编号959611) 资助

摘　　要：测定了湘西及邻区晚震旦世—早二叠世25 个黑色岩系样品的LaCe 和SmNd 同位素数据。它们的εCe(t) 和εNd(t) 值分别变化在- 1 .6 ～+ 2 .6 和- 1 .4 ～- 11 .0 范围内,δCe 值为0 .28 ～1 .68 ,T2 DM 年龄为1358 ～2207 Ma。在εCe(t) - εNd(t) 图上,全部数据点可以分成3 个区,不同的分区显示了黑色岩系的不同沉积环境与构造背景。在沉积环境研究中Ce 同位素是有用的地球化学示踪器。Ce isotopic data and Nd isotopic data were determined for 25 samples of late Sinian—early Permian black rock series from western Hunan and adjacent rigions. ε Ce ( t ) and ε Nd ( t ) values of 25 samples are -1.6～+2.6 and -1.4～-11.0, respectively,δ Ce are 0.28～1.68,and T 2DM ages are 1358～2207Ma. All data points in the ε Ce ( t ) vs.ε Nd ( t ) diagram could be divided into three different fields(A,B,C),which show different depositional environments and structural backgrounds of black rock series in ocean basins.These results indicate that the Ce isotope is a useful geochemical tracer in determining the depositional and structural environments of the studied marine sedimentary rocks such as black rock series.

关 键 词：沉积环境 黑色岩系 晚震旦世 早二叠世 铈同位素 

分 类 号：P584[天文地球—岩石学] P588.2[天文地球—地质学]