贵州遵义牛蹄塘组黑色岩系有机质的稀土元素地球化学研究  

REE GEOCHEMISTRY OF ORGANIC MATTER FROM BLACK SHALES OF THE NIUTITANG FORMATION,ZUNYI,GUIZHOU PROVINCE

作　　者：皮道会[1,2] 刘丛强[1] 邓海琳[1] Graham Shields 

机构地区：[1]中国科学院地球化学研究所,贵州贵阳550002 [2]中国科学院研究生院,北京100039 [3]James Cook University,Townsville Q.4811

出　　处：《矿物学报》2008年第3期303-310,共8页Acta Mineralogica Sinica

基　　金：中国科学院院长特别基金项目(2002);国家科技部中捷国际合作项目(35-20)

摘　　要：以贵州遵义寒武纪初牛蹄塘组黑色岩系的有机质为分析对象，对22个样品的稀土元素（REE）组成进行了研究，结果表明：①有机质的ΣREE占全岩ΣREE的10%左右，且其REE标准化配分曲线不同于全岩的。由于有机质主要来自海洋上层水体中的微生物，因而可以认为其REE特征代表的是古海洋上层水体的稀土元素组成特征；②有机质的REE总量变化于11.6×10＆-6-548×10＆-6之间，Ce异常系数变化于0.40-0.92之间，Eu异常系数变化于0.59-1.14之间。有机质的Ce异常系数和LaN/CeN值在剖面上显示明显的变化，指示研究区经历了大陆斜坡到大洋盆地再到大陆边缘的环境，指示在寒武纪初存在一次海侵。REE geochemistry of organic matter from black shales of the Niutitang Formation, Zunyi, Guizhou Province, was investigated in this paper. Results showed that ： （ 1 ） REE in organic matter accounted for only ten percent of REE in the bulk rocks, and showed different PAAS-normalized distribution spectra from those of the bulk rocks. For the reason that organic matter in the rocks was derived mainly from microorganisms living in upper sea-water, it can be deduced that REE in organic matter might represent the REE characteristics of the upper sea-water. （2） The total concentrations of rare earth element in organic matter varied between 11.6 × 10^-6 - 548 × 10^-6, with Ce anomaly between 0. 40 - 0. 92, and Eu anomaly between 0. 59 - 1.14. The changing trend of δCe and LaN/CeN in the Zhong- nancun section indicated that the sedimentary environment changed from the continental slope in the base to the oceanic basin at the middle, and again back to the continental margin at the top, implying that there occurred a transgression event during the Early Cambrian.

关 键 词：稀土元素 有机质 黑色岩系 牛蹄塘组 遵义 

分 类 号：P581[天文地球—岩石学] P588.22[天文地球—地质学]