渤海湾盆地车西洼陷沙三-沙四段古环境演化特征  

Characteristics of Palaeoenvironmental Evolution in the Shasan-Shasi Section of the Chexi Depression in the Bohai Bay Basin

作　　者：刘杰 李敏[1] 陈盼盼[1] 李存磊[1] 段长江 王宝春 夏晓朵 孟龙起 LIU Jie;LI Min;CHEN Pan-Pan;LI Cun-Lei;DUAN Chang-Jiang;WANG Bao-Chun;XIA Xiao-Duo;MENG Long-Qi(Liaoning University of Petroleum and Chemical Technology,Fushun 113005,Liaoning,China;Xi'an Engineering Investigation&Design Research Institute of China National Nonferrous Metals Industry Co.,Ltd.,Xi'an 710054,Shanxi,China;CNOOC EnerTech-Drilling&Production Co.,Tianjin 300452,China)

机构地区：[1]辽宁石油化工大学,辽宁抚顺113005 [2]中国有色金属工业西安勘察设计研究院有限公司,陕西西安710054 [3]中海油能源发展股份有限公司工程技术分公司,天津300452

出　　处：《华南地质》2025年第1期136-147,共12页South China Geology

基　　金：陕西省能源化工研究院地质科研项目(2016YFE0102500-08)。

摘　　要：由于浅海陆架区重力流沉积具有特征不典型和规模较小等特点,以往的研究多仅限于对其进行简单的描述,目前对其沉积特征与成因机理的认识还不够充分,对影响其发展的主控因素和作用机理尚不清楚。本文以渤海湾盆地车西洼陷沙三-沙四段的重力流沉积为研究对象,分析形成车西洼陷沙三-沙四段重力流发育特征的古环境条件,总结沉积模式,并探讨其地质意义。车西洼陷沙三-沙四段的古气候指数C以及Fe/Mn指标均指示沙四段沉积期气候干燥,沙三段沉积期整体较沙四段沉积期湿度更高,主要为半湿润-湿润气候。Sr/Ba指标指示沙四段沉积期处于咸水环境中,沙三段沉积期处于淡水-半咸水环境中。依据研究区沉积物分布规律以及沉积构造特征等计算出该区沙三段和沙四段的平均最大古水深分别为60.07 m和20.32 m。根据车西洼陷沙三段及沙四段的岩心特征分析,结合该区沉积环境及地形研究认为沙三段发育滑塌沉积、碎屑流沉积、浊流沉积,沙四段发育泥石流沉积。Due to the untypical features and comparatively smaller scale,previous studies on gravity flow deposits in shallow marine shelf areas are mostly limited to simple descriptions,so the understanding of their sedimentary characteristics and genesis mechanisms is not sufficient,and the main controlling factors and mechanisms affecting their development are not known.In this paper,the gravity flow deposits of the Shasan-Shasi section in Chexi Depression,Bohai Bay Basin have been studied,the palaeoenvironmental conditions and depositional patterns affecting the developmental characteristics of gravity currents in the Shasan-Shasan section of the Chexi Depression has been analyzed,and geological significance has been further discussed.The palaeoclimate index C and the Fe/Mn index of the Shasan-Shasi section sediments in Chexi Depressionindicate that during the sedimentation period of Shasi section the climate has been dry, and slightly morehumid during the sedimentation period of the Shasan section, mainly semihumid to humid. The Sr/Ba indexindicates that the Shasi section sediments has been deposited in a brackish water environment, while theShasan section sediments has been deposited in a fresh-brackish water environment. Based on the sedimentdistribution pattern and the sedimentary structural characteristics in the study area, it could be calculated thatthe average maximum paleowater depths of the Shasan and Shasi section would be 60.07 m and 20.32 m,respectively. Based on the characteristics of the core samples of the Shasan-Shasi section in ChexiDepression, combined with the sedimentary environment and topography study in the area, it can be deducedthat the Shasan section has developed slump deposits, sediment flow deposits, turbidity currents deposits,while the Shasi section has developed mudstone flow deposits.

关 键 词：渤海湾盆地 车西洼陷 沙三-沙四段 重力流沉积 古环境演化 

分 类 号：P53[天文地球—古生物学与地层学]