安徽石台早寒武世黑色岩系稀土元素地球化学特征及其地质意义  

REE geochemical characteristics of the Lower Cambrian black shale series in Shitai area,Anhui Province,and their geological significance

作　　者：徐晓春[1] 王文俊[1] 熊亚平[1] 褚平利[1] 房海波[1] 赵丽丽[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《岩石矿物学杂志》2009年第2期118-128,共11页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金项目(40472052);安徽省国土资源勘查项目(AHGTT2006-4)

摘　　要：安徽石台地区发育早寒武世黑色岩系，岩石地层单元为下寒武统荷塘组和黄柏岭组。稀土元素地球化学研究表明，黑色岩系稀土总量不富集，轻稀土较重稀土富集；δEu=0．81～2．32，平均1．1；δCe=0．52～0．97，平均0．77。剖面自下而上δCe值和δEu值规律变化，δCe值由大渐小再增大，但总体逐渐增大，δEu值总体变化则与之相反。稀土元素地球化学特征反映该区早寒武世曾发生过一次明显的海侵-海退过程，黑色岩系为正常海水与热水混合沉积的产物，形成于缺氧还原状态过渡到半还原-弱氧化状态的过程中，沉积环境为干燥气候条件下相对较深的浅海斜坡环境。The black shale series in Early Cambrian Hetang Formation and Huangboling Formation are well developed in Shitai area, Anhui Province. They have distinguished REE geochemical characteristics, i. e. , total REE contents are very low; LREE are more abundant than HREE; δEu =0.81 -2.32 （1.1 on average）, δCe =0.52 -0.97 （0.77 on average）. The δEu and δCe values change regularly, i.e. , the δCe values decrease and then increase from bottom to top in the sedimentary section, but with an increasing tendency on the whole, whereas things are just the opposite for δEu values. REE geochemical characteristics and their systematic changes in the sedimentary section suggest that there existed a process of ingression-regression in this area in the early Cambrian period. The black shale series resulted from the mixing between normal seawater sediments and hot seawater sediments and were deposited under the transitional condition from reduction to semi-reduction and weak oxidation in a shallow-sea clinoform zone of a relatively deep sea environment with dry climate.

关 键 词：稀土元素 地球化学 黑色岩系 下寒武统 安徽石台 

分 类 号：P595[天文地球—地球化学] O614.33[天文地球—地质学]