| 鄂尔多斯盆地早侏罗世富县期沉积演化: 大洋缺氧事件前后陆地气候变化的响应* |
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| 引用本文： | 李昌昊,葛禹,金鑫,时志强.鄂尔多斯盆地早侏罗世富县期沉积演化: 大洋缺氧事件前后陆地气候变化的响应*[J].古地理学报,1999,22(4):697-712. |
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| 作者姓名： | 李昌昊 葛禹 金鑫 时志强 |
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| 作者单位： | 1.成都理工大学沉积地质研究院,四川成都 610059;2.成都理工大学油气藏地质及开发工程国家重点实验室,四川成都 610059 |
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| 基金项目： | National Science and Technology Major Project(No.2017ZX05001) |
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| 摘 要： | 托阿尔期早期早侏罗世大洋缺氧事件(T-OAE,~183.8 Ma)是一次全球性的地质事件,鄂尔多斯盆地下侏罗统富县组记录了此次地质事件的陆地响应过程。主要基于盆地东缘野外地质调查、扫描电镜及薄片分析,本次研究描述了盆地东北部富县组岩性、颜色和沉积序列,利用前人研究成果总结了富县期岩相古地理变化规律及沉积模式,认为富县期经历了由干旱到湿润的古气候变化: 富县组下部含植物化石较为丰富的白色砂砾岩及黑色、灰色泥页岩沉积于湿润气候时期,对应着盆地下切河谷发育期和填平补齐期; 而上覆的罕见植物化石的杂色、红色泥页岩为(富县期晚期)相对平坦地形条件下的沉积,对应着早、中侏罗世湿润气候背景下的一次干旱气候脉动,为托阿尔期大洋缺氧事件在陆相环境的气候响应,可由此进行富县组区域等时性对比。研究认为“粗富县”为下切谷内河流充填沉积, “细富县”形成于湖泊环境或河漫环境, “黑富县”和“白富县”是湿润气候条件下沉积产物,而“红富县”和“杂富县”为T-OAE期后干旱条件下形成。
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| 关 键 词： | 侏罗纪古气候 富县组 托阿尔期海洋缺氧事件 岩相古地理 鄂尔多斯盆地 |
| 收稿时间： | 01 July 2019 |
Unconformities formed during the P-T transition in the northwestern Junggar Basin: Nature,evolution and implications |
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| Li Pan,Li Yong-Qiang,Jing Jian-Bo,Cao Zheng-Lin,Yuan Xuan-Jun.Unconformities formed during the P-T transition in the northwestern Junggar Basin: Nature,evolution and implications[J].Journal of Palaeogeography,1999,22(4):697-712. |
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| Authors: | Li Pan Li Yong-Qiang Jing Jian-Bo Cao Zheng-Lin Yuan Xuan-Jun |
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| Institution: | 1.Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;2.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China |
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| Abstract: | Late Permian to Early Triassic represents a significant transition period of the Junggar Basin,resulting in the formation of widespread characteristic unconformities. In this paper,the nature,evolution and implications of these unconformities in the northwestern Junggar Basin are explored,based on seismic and borehole data. This study shows that during the P-T transition two main phases of unconformities were present in the study area,including P3/P2 and T1/P3,with the former expressed mainly as a major angular unconformity and later as a minor parallel or sub-parallel unconformity. Noticeably,the two unconformities are amalgamated to form a superimposed one beneath the Lower Triassic in the north,whereas in the south they co-exist with the Upper Permian in between. Their evolution is characterized by four distinct stages: formation of the major unconformity,its partial onlapping by the Upper Permian,formation of the minor and superimposed unconformity,and their onlapping by the Triassic. The nature and evolution of these unconformities help elucidate the relative influence of the late-stage Hercynian and early-stage Indosinian orogenies,the wedge-shaped connotation of stratigraphic record,and the assignment of tectonic sequences to the Upper Permian and Lower Triassic. The results from this study also indicate that the unconformities and relevant stratigraphy during the P-T transition comprise favorable oil-gas migration pathways,reservoir-seal assemblages and various traps,and are thus of great significance for hydrocarbon exploration. |
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| Keywords: | Mahu sag Baikouquan Formation Wuerhe Formation unconformity P-T transition |
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