古地理学报2025，Vol.27Issue(5)：1157-1172,16.DOI:10.7605/gdlxb.2025.066
南堡凹陷东营组三段页岩特征及其对古环境和有机质富集的启示
Characterization of shale in the Member 3 of Dongying Formation of Nanpu sag:implications for palaeoenvironment and organic matter accumulation mechanism
摘要
Abstract
To evaluate the shale oil exploration potential of the member 3 of the Paleogene Dongying Formation(Ed3)in the Nanpu sag,this study investigates paleoclimate and paleoenvironmental varia-tions and their impacts on organic matter accumulation through mineralogical and geochemical analyses of 21 shale samples.Results reveal strong heterogeneity in the Ed3 shale,with TOC ranging from 0.30％to 2.66％,S1+S2 from 0.44 to 11.41mg/g,and HI from 57 to 466 mg/g TOC,predominantly charac-terized by Type Ⅱ kerogen at low to mature thermal maturity stages.Multiple geochemical proxies indicate that a semi-humid to semi-arid paleoclimate during the Ed3 deposition influenced palaeoenvironmental fluctuations.From bottom to top,paleowater depth transitioned from shallow to deep and back to shallow,paleosalinity shifted from brackish to fresh and back to brackish,and redox conditions evolved from weakly oxidizing to weakly reducing and back to weakly oxidizing.These environmental fluctuations controlled differential organic matter accumulation.Under humid climates,high paleoproductivity and anoxic condi-tions in deeper waters promoted efficient organic matter burial and enrichment.Conversely,under arid climates,moderate paleoproductivity and oxic conditions in shallower waters resulted in lower organic matter burial and enrichment.The established model of organic-rich mudstone development provides a foundation for selecting favorable lacustrine shale oil exploration intervals.关键词
页岩油/古气候/古环境/有机质富集/东营组/南堡凹陷/渤海湾盆地Key words
shale oil/palaeoclimate/palaeoenvironment/organic matter accumulation/Dongying Formation/Nanpu sag/Bohai Bay Basin分类
天文与地球科学引用本文复制引用
孟令箭,雷闯,张云峰,邹娟,杨荣超,高永亮..南堡凹陷东营组三段页岩特征及其对古环境和有机质富集的启示[J].古地理学报,2025,27(5):1157-1172,16.基金项目
中国石油股份公司重大科技专项子课题(编号:2023YQX20107),唐山市科技计划项目(编号:22130213H)和辽宁省矿产资源绿色开发重点实验室开放课题(编号:LNTU/GDMR-2316)联合资助.[Co-funded by the Major Science and Technology Project of China Petroleum Corporation(No.2023YQX20107),the Science and Technology Planning Project of Tangshan City,China(No.22130213H),and the Liaoning Key Laboratory of Green Development of Mineral Resources,China(No.LNTU/GDMR-2316)] （编号:2023YQX20107）
