鄂尔多斯盆地延长组深水块状砂岩“泥包砾”结构成因机制

发布时间：2018-03-04 18:48

本文选题：“泥包砾”结构　切入点：延长组　出处：《中国石油大学学报(自然科学版)》2017年04期 　论文类型：期刊论文

【摘要】：通过元素地球化学分析、X-衍射全岩分析、岩石薄片分析等试验方法对鄂尔多斯盆地延长组块状砂岩中"泥包砾"结构成因机制进行研究。结果表明:该结构中泥质包壳层Fe/Mn值较低、MnO_2含量较高,Th/U值较高、δU小于1,Sr/Ba值较低,反映近岸、偏氧化及低古盐度的浅水地球化学特征,和与其伴生的半深湖层状泥岩的沉积介质环境存在较大差异性;结构中内核的主要成分为砂质、泥质或白云石团块,形成于滨浅湖或三角洲前缘环境;"泥包砾"结构非瞬态形成,而是贯穿长7—长6_3期三角洲前缘砂泥岩软沉积物往深湖区块体搬运的全过程,经历浅湖相团块形成、结构初始形成、岩性混合转移、最终停积定型4个阶段。
[Abstract]:By means of element geochemistry analysis and X-ray diffraction analysis of the whole rock, The genetic mechanism of "mud-covered gravel" structure in block sandstone of Yanchang formation in Ordos Basin was studied by means of thin slice analysis and other test methods. The results show that the Fe/Mn value of muddy cladding layer is lower than that of MNO _ 2, and the content of Th / U is higher, and 未 U is lower than 1g Sr-Ba in this structure. It reflects the shallow water geochemical characteristics of inshore, partial oxidation and low paleosalinity, and the sedimentary media environment of semi-deep lake bedded mudstone associated with it is quite different, and the main components of the core in the structure are sandy, muddy or dolomite mass. It is formed in the coastal shallow lake or delta front environment, the "mud-covered gravel" structure is not transient formed, but runs through the whole process of transporting the sand and mudstone soft sediment from the delta front to the deep lake area in Chang7-Chang63 stage, and the formation of shallow lacustrine block, and the formation of the shallow lacustrine block, and the formation of the shallow lacustrine block. The structure is formed initially, the lithology is mixed and transferred, and finally the deposition is stopped and finalized.
【作者单位】：西南石油大学地球科学与技术学院;中国石油勘探开发研究院西北分院;中国石油长庆油田分公司第十采油厂;中国石油长庆油田分公司勘探开发研究院;
【基金】：国家科技重大专项(2011ZX05001-003)
【分类号】：P588.212.3;P618.13

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