川东北地区二叠纪晚期古海洋环境与有机质富集  

Marine Redox Environment and Organic Accumulation in Northeastern Sichuan Basin During the Late Permian

作　　者：葛小瞳 汪远征 陈代钊[5,6,7] 张恭境 黄泰誉 李王鹏 GE XiaoTong;WANG YuanZheng;CHEN DaiZhao;ZHANG GongJing;HUANG TaiYu;LI WangPeng(State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development,Beijing 102206,China;SINOPEC Key Laboratory of Shale Oil/Gas Exploration and Production Technology,Beijing 102206,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China;Wuxi Research Institute of Petroleum Geology,Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi,Jiangsu 214126,China;Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China;General Prospecting Institute,China National Administration of Coal Geology,Beijing 100039,China)

机构地区：[1]页岩油气富集机理与高效开发全国重点实验室,北京102206 [2]中国石化页岩油气勘探开发重点实验室,北京102206 [3]中国石化石油勘探开发研究院,北京102206 [4]中国石化石油勘探开发研究院,无锡石油地质研究所,江苏无锡214126 [5]中国科学院地质与地球物理研究所,中国科学院新生代地质与环境重点实验室,北京100029 [6]中国科学院地球科学研究院,北京100029 [7]中国科学院大学地球与行星科学学院,北京100049 [8]太原理工大学矿业工程学院,太原030024 [9]中国煤炭地质总局勘查研究总院,北京100039

出　　处：《沉积学报》2024年第3期757-773,共17页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(91755210)。

摘　　要：【目的】二叠纪晚期是一个关键的地质历史时期,地球系统在构造、火山活动、气候、古海洋环境和生物群落等方面都发生了巨大变化。重建这一时期的古地理、古气候、古海洋环境有助于理解不同地质因素的相互作用机制,及其对该时期富有机质岩系及生物演化的重要影响。【方法】通过对四川盆地建峰剖面上二叠统深水序列的沉积学和地球化学(主微量元素含量、有机碳同位素、总有机碳含量)研究,明确了该时期的古地理环境,重建了海洋初级生产力和氧化还原环境的时空演化,探讨了多种因素对有机质富集的控制作用。【结果】建峰剖面的氧化还原环境依次经历了氧化—铁化—硫化—氧化四个阶段(Ⅰ~Ⅳ),初级生产力和陆源输入均在阶段Ⅱ_(2)和阶段Ⅲ较高,上升流在阶段Ⅱ_(2)、Ⅱ_(3)、Ⅲ和Ⅳ较为发育,火山活动仅在阶段IV较为频繁。因此,建峰剖面高初级生产力可能主要受陆源物质输入的影响,而上升流的影响次之,火山活动的贡献较小。【结论】结合西北乡剖面,推测该时期川东北地区硫化水团的形成受高生产力的控制,其上侵、下退则与海平面的波动有关;大隆组沉积期间盆地中部的初级生产力受上升流影响更大,而盆地边缘的初级生产力受陆源输入影响更大;初级生产力对大隆组的有机质富集起主导作用。[Objective]The Late Permian was a critical interval in geological history,with dramatic changes in tectonics,paleoclimate,paleo-oceanic environment,volcanic activities,and the biosphere.Reconstruction of the paleogeography,paleoclimate,and paleo-oceanic environment during this interval could provide a more complete picture of the interactions and relationships among different geological factors,as well as their influence on organic matter enrichment and the evolution of the biosphere.[Methods]Organic-rich rock series were widely deposited during this period in the Sichuan Basin of the Upper Yangtze Block,providing insights into the co-evolution of the geosphere and biosphere.To better address the coeval temporal and spatial changes in the paleogeographic settings,paleo-oceanic environment,primary productivity,and organic enrichment,we conducted a detailed sedimentological investigation integrated(major and trace)element contents,organic carbon isotopes and total organic carbon(TOC)contents in the Jianfeng section,located in an intrashelf basin in northeastern Sichuan Basin.[Results]The redox-sensitive trace element data(Mo_(XS),U_(XS),V_(XS) contents,Mo_(XS)/U_(XS) ratios,and Mo_(EF)-U_(EF) relationship)show that the redox environment of the Jianfeng section has experienced four intervals(I-Ⅳ).Interval Ⅰ(0-10.35 m,spanning from the upper part of the Wuchiaping Formation to the lower part of the Dalong Formation)was dominated by an oxic environment during deposition,Interval Ⅱ(10.35-23.35 m,the middle Dalong Formation)experienced a ferruginous-dominant anoxic condition,Interval Ⅲ(23.35-27.00 m,the upper Dalong Formation)was mainly a euxinic environment,and Interval Ⅳ(27.00-34.05 m,from the top of the Dalong Formation to the bottom of the Changhsing Formation)was dominated by an oxic or suboxic environment.Compared with the Xibeixiang section in the deeper water of the Kaijiang-Liangping trough,the redox environment in the intrashelf basin exhibits spatiotemporal heterogeneity.The nutrient-limiting elemen

关 键 词：二叠纪晚期 川东北地区 氧化还原环境 初级生产力 有机质富集 

分 类 号：P512.2[天文地球—地质学]