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    河南登封晚古生代层序地层及聚煤特征研究

    Sequence stratigraphic analysis and characteristics of Late Paleozoic coal accumulation in Dengfeng, Henan Province

    • 摘要: 提要:运用露头、钻井岩心层序地层学的有关理论方法,对蹬槽剖面的晚古生代地层进行了详细的沉积学和层序地层学研究,共识别出8个三级层序界面,把本研究区域晚古生代地层划分为7个三级层序。S1大致相当于本溪组;S2大致相当于太原组;S3大致相当于山西组;S4和S5分别对应下石盒子组的上下部分;S6对应上石盒子组;S7对应石千峰组。在这些层序中,低位体系域往往以发育三角洲平原分流河道相砂砾岩、或残积相风化壳、或滨湖相中细砂岩为特征,而水进体系域多障壁岛-潟湖相泥岩和粉砂岩、三角洲前缘相砂泥层以及浅湖相细砂岩为主,高位体系域则主要为浅海相碳酸盐岩、前三角洲相泥岩及富泥质的浅湖相沉积序列。层序S1~层序S2物源不丰富,聚煤作用主要发生在海侵初期或海退时期;层序S3~层序S6物源相对丰富,聚煤作用主要出现在最大海泛附近。

       

      Abstract: Abstract:Principles and methods of sequence stratigraphy for outcrops and drilling cores were used to reconstruct the Upper Paleozoic sequence stratigraphic framework in Dengcao profile. Extensive investigation into outcrop and borehole data reveals that a total of 8 third-order sequence boundaries and 7 third-order sequences are developed in the Upper Paleozoic strata in the Henan part of southern North China Basin. S1 is equivalent to the Benxi Formation, S2 to the Taiyuan Formation, S3 to the Shanxi Formation; S4 and S5 to the Xiashihezi Formation, S6 to the Shanshihezi Formation, and S7 to the Shiqianfeng Formation. Within these sequences, the lowstand systems tracts are represented by conglomerates and sandstones of the delta plain distributary channel and lakeshore and the weathered crust of eluvial facies. The transgressive systems tracts are dominated by coastal-shallow lacustrine mudstones and siltstones and barrier island-salt lagoon and delta front, and the highstand systems tracts are mainly composed of carbonate rocks and mudstone-abundant successions. Coal accumulation of sequence 1~sequence 2 occurred mainly in the early transgressive or regressive period with poor sources, whereas coal accumulation of sequence 3~sequence 6 occurred mainly in the largest pan-sea with rich sources.

       

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