摘要
川东南—黔中及其周边地区自晚震旦世早期以来沉积环境受后期构造运动改造的影响很大,对该区下组合烃源岩沉积古环境进行恢复有重要的地质意义。对研究区样品的稀土元素地球化学分析结果表明,该区泥岩和页岩的稀土总量最高,(∑LREE/∑HREE)和(La/Yb)_N及(La/Sm)_N等显示,烃源岩具有轻稀土元素富集的配分型式,整体上随地层时代变新陆源影响增强;轻稀土元素之间分异中等,重稀土元素之间分异不明显。δCe均呈现负异常,并随地层变老和灰岩岩性异常增强,反映了研究区总体沉积环境为较深海水环境。Eu呈弱的负异常,只有寒武系渣拉沟群、都柳江组和牛蹄塘组样品的δEu呈正异常,印证了黔东南地区当时处在深水陆棚和远离陆源的沉积环境。
Great transformation of sedimentary environment caused by late tectonic movement occurred in South China especially in Chuandongnan-Qianzhong area since early period of late Sinian.It has important geological signification for this region to reveal the paleo-environment of lower assemblage source rocks. The geochemistry analysis indicates that the amount of REE of mudstone and shale are the highest.The ratios of LREE/HREE,(La/Yb) N and(La/Sm) N show the LREE enriched in the source rocks,the medium differentiation among LREE but not very evident among HREE,and the value elevated with the strata and terrigenous effect enhanced.δCe appears negative anomaly and enhances with the strata age and the appearance of limestone,which reflects deeper marine environment.δEu of the area appears weak negative anomaly except for Zhalagou group,Duliujiang and Niutitang formation of Cambrian.This phenomenon just proves the deep shelf and off continental environments in Chuandongnan.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2009年第3期41-43,共3页
Petroleum Geology and Recovery Efficiency
基金
国家自然科学基金重点项目(40730422)
