四川盆地东南缘中上寒武统白云岩稀土元素特征及成因意义——以贵州毕节长树田剖面为例  

THE REE GEOCHEMICAL CHARACTERISTICS OF MIDDLE-UPPER CAMBRIAN DOLOMITE IN SOUTHEAST SICHUAN BASIN AND ITS SIGNIFICANCE——A CASE STUDY OF CHANGSHUTIAN PROFILE IN BIJIE,GUIZHOU

作　　者：刘建清[1] 林家善[1] 冯伟明[1] 赵瞻[1] 黄学平[1] 

机构地区：[1]成都地质矿产研究所沉积与能源地质研究室,四川成都610082

出　　处：《矿物岩石》2014年第1期87-94,共8页Mineralogy and Petrology

基　　金：成都理工大学"油气藏地质及开发工程"国家重点实验室开放研究基金(PLC200901)

摘　　要：以野外剖面测量及沉积相分析为基础,结合室内薄片鉴定,分析了贵州毕节长树田中上寒武统白云岩稀土元素特征,认为该区白云岩普遍具有交代残余结构和ΣREE较高的特点,且以下部含灰泥质白云岩ΣREE含量最高。该区白云岩下部REE高含量主要来自陆源碎屑注入和粘土矿物的吸附作用,而白云岩整体ΣREE含量较高,与沉积时高咸度卤水在早期埋藏作用中渗透回流交代有着密切的关系。δEu和δCe相比,δCe值较大,反映出弱氧化和高碱度沉积环境,Ce具弱富集特征,与其沉积时处于局限台地环境,水体较浅,易于氧化,且水体较咸,处于碱性沉积环境,沉积了石膏、岩盐等盐类矿物等地质事实相吻合。Based on the analysis of field survey, sedimentary facies and rock thin sections, the dolomite REE characteristics from the Changshutian profile in Bijie,Guizhou has been conducted. The dolomite has metasomatic relict texture with high amount of REE and with higher REE in bottom muddy calcite dolomite in comparison with upper dolomite. Higher amount of Y.REE in bottom is resulted from clasolite injection and clay adsorption The high amount of Y REE in dolo- mite is duo to high salinity brine seepage reflux replacement in early bury period. The index of Ce is larger in comparison with Eu, reflecting slight oxidizing environment, high alkalinity and weak concentration of Ce. The characteristics of Ce coincide with the conditions of restricted plat- form, shallow water, salty water, the alkaline sedimentary environment, plaster and halite in the strata.

关 键 词：白云岩成因 稀土元素 贵州毕节 

分 类 号：P588.245[天文地球—岩石学]