石油实验地质2024，Vol.46Issue(3)：522-531,10.DOI:10.11781/sysydz202403522
渤海湾盆地东营凹陷古近系富碳酸盐页岩沉积微相组合及沉积环境分析
Sedimentary microfacies and environment of Paleogene carbonate-rich shale in Dongying Sag,Bohai Bay Basin
摘要
Abstract
The identification,classification,and integration of microfacies characteristics of carbonate-rich shale in the Dongying Sag of the Bohai Bay Basin are fundamental for understanding the sedimentary origin and spatial structure of related sediments.Leveraging core and rock thin section data,along with analytical techniques such as X-ray diffraction and scanning electron microscopy,high-resolution core sampling and testing were conducted to analyze the rock mineralogy and paleontology of the carbonate-rich shale in the slope zone of the Dongying Sag.The research findings identified the presence of 10 types of microfacies within the carbonate-rich shale,including algal mat microfacies and shell shale microfacies.These microfacies combined in various ways to form a spectrum of microfacies combinations,exhibiting shale phase transition characteristics on a meter scale.Corresponding to the different stages of saline lake evolution in the Dongying Sag,three types of rock microfacies combinations emerged:shallow water evaporite microfacies combination,oscillatory semi-deep water shale microfacies combina-tion,and oscillatory deep water shale microfacies combination.These combinations were typically controlled by the cyclical rise and fall of lake levels against a backdrop of high-frequency oscillations.In the upper submember of the fourth member of the Shahejie Formation,from bottom to top,as the climate became more humid and hot,weathering intensified,lake levels rose and lake salinity decreased,the proportion of oscillatory deep water shale microfacies combinations gradually increased,while that of shallow water evaporite microfacies combinations decreased.This series of upward-deepening depositional cycles recorded the continuous subsidence and co-evolu-tion of biology and environment during the middle Eocene in the Dongying Sag.关键词
沉积微相组合/沉积环境/成因机理/页岩/沙河街组/东营凹陷/渤海湾盆地Key words
sedimentary microfacies combination/sedimentary environment/genetic mechanism/shale/Shahe-jie Formation/Dongying Sag/Bohai Bay Basin分类
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王伟庆,李朋波,李博,方正伟,王玉环..渤海湾盆地东营凹陷古近系富碳酸盐页岩沉积微相组合及沉积环境分析[J].石油实验地质,2024,46(3):522-531,10.基金项目
中国石化股份公司重点实验室项目"济阳坳陷古近系细粒沉积特征与古湖泊演化"(KJ21042)资助. （KJ21042）
