鄂尔多斯盆地东缘太原组风暴沉积特征及环境模式  

Storm Deposit Characteristics and Their Environmental Model in the Taiyuan Formation on the Eastern Margin of the Ordos Basin

作　　者：宋慧波[1] 张彬 于振锋 金毅[1,3] 胡斌 牛永斌[1] 张立军[1] SONG HuiBo;ZHANG Bin;YU ZhenFeng;JIN Yi;HU Bin;NIU YongBin;ZHANG LiJun(School of Resources and Evironment,Henan Polytechnic University,Jiaozuo,Henan 454000,China;Shanxi Lanyan Coalbed Methane Engineering Research Co.,Ltd.,Jincheng,Shanxi 048000,China;Henan Key Laboratory of Unconventional Coal Measure Resources,Jiaozuo,Henan 454000,China)

机构地区：[1]河南理工大学资源环境学院,河南焦作454000 [2]山西蓝焰煤层气工程研究有限责任公司,山西晋城048000 [3]河南省煤系非常规资源成藏与开发重点实验室,河南焦作454000

出　　处：《沉积学报》2024年第4期1370-1383,共14页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(41972175);河南省高校科技创新团队项目(21IRTSTHN007);河南理工大学创新型科研团队项目(T2022-05);山西省重点研发计划项目(2022ZDYF050)。

摘　　要：【目的】鄂尔多斯盆地东缘乡宁地区甘草山一带下二叠统太原组灰岩中发育多层风暴沉积,主要分布在L2、L3、L4和L5灰岩层中。【方法】基于岩性、沉积构造、遗迹化石和沉积序列研究,对该区碳酸盐岩风暴事件沉积序列中的侵蚀基底构造与生物碎屑滞积层、粒序层、纹理层、生物成因构造(遗迹化石)和泥灰岩或灰质泥岩层的主要特征进行了较详细论述。【结果】根据不同灰岩层中风暴沉积序列的垂向组成特点,识别出5种风暴沉积类型:类型A沉积序列由波状侵蚀基底和粒序层两个沉积单元构成,发育于近岸正常天气浪基面之上的滨岸带;类型B沉积序列以波状侵蚀基底、粒序层和纹理层(丘状—洼状交错层理)三个层段为特征,产生于潮下带、正常天气浪基面与风暴浪基面之间的上部沉积环境;类型C由波状侵蚀基底、粒序层、纹理层(丘状—洼状交错层理及缓波状层理)和顶部泥灰岩层等4个沉积单元组成,形成于正常天气浪基面与风暴浪基面之间的下部沉积环境;类型D沉积序列由基底侵蚀及生物碎屑滞积层、粒序层、生物扰动层和泥灰岩层组成,出现于风暴浪基面附近的沉积环境;类型E则以微波状侵蚀基底、薄层粒序层、遗迹化石层和泥灰岩层构成为特点,发生在风暴浪基面附近及之下的浅海沉积环境。【结论】该研究不仅对鄂尔多斯盆地下二叠统太原组碳酸盐岩及其沉积环境提出了新的认识,而且可以对该地层中的油气资源勘探与开发提供沉积环境分析和古地理重建方面的事件沉积佐证。[Objective]Multiple layer storm deposits are distributed in the Lower Permian Taiyuan Formation car⁃bonate rocks located at the Gancaoshan zone of Xiangning county on the eastern margin of the Ordos Basin.[Methods]These are primarily distributed in limestone beds L2,L3,and L4.Based on the lithology,sedimentary structure,trace fossils and sedimentary sequence,the main characteristics of the deposit sequence consisting of the eroded basement structure and bioclastic lags,graded bedding,laminated unit,bioturbation structures(trace fossils),and marlstone or calcareous mudstone unit in carbonate rocks are discussed in detail.[Results]From the vertical component features of storm deposits sequence in different limestone beds,five types of tempestite deposit sequences were identified:Type A is comprised of a wavy bottom erosion surface and graded bedding,developing in the near shore zone above the fair weather wave base.Type B is characterized by a wavy bottom erosion surface,graded bedding,and laminated unit(Hummocky⁃swaley cross-bedding)and is generated in the subtidal zone,name⁃ly the upper zone between the fair weather and storm wave base.Type C is composed of a wavy bottom erosion sur⁃face,graded bedding,laminated unit(Hummocky⁃swaley cross-bedding and gently wavy bedding),and marlstone unit,forming in the lower zone between the fair weather and storm wave base.Type D consists of a wavy bottom ero⁃sion surface with bioclastic lags,graded bedding,bioturbation structure,and marlstone unit,appearing mainly near the storm wave base.Type E consists of a slight fluctuation bottom erosion surface,thin-bedded graded bedding,ichnofossil-bearing unit,and marlstone unit,occurring in the shallow marine environment near/below the storm wave base[.Conclusion]This result not only provides new understanding of the Lower Permian Taiyuan Formation carbon⁃ate rocks and their sedimentary environment in the Ordos Basin,but also can provide evidence of sedimentary envi⁃ronment analysis and palaeogeographic reconstruction

关 键 词：太原组 风暴沉积 沉积环境 下二叠统 鄂尔多斯盆地 

分 类 号：P512.2[天文地球—地质学]