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现代地质 ›› 2006, Vol. 20 ›› Issue (1): 49-60.

• 沉积地层与油气 • 上一篇    下一篇

上扬子区震旦系层序地层划分

梅冥相1,2,聂瑞贞1,2,张海1,2,陈永红1,2,孟晓庆1,2   

  1. 1中国地质大学地质过程与矿产资源国家重点实验室,北京100083;2中国地质大学地球科学与资源学院,北京100083
  • 收稿日期:2005-09-25 修回日期:2005-11-20 出版日期:2006-01-20 发布日期:2006-01-20
  • 作者简介:梅冥相,男,教授,博士生导师,1965年出生,沉积学与地层学专业,主要从事沉积学与地层学的研究工作。
  • 基金资助:

    中国石化科技工程重点项目(QZ-2005-06)

Sequence-Stratigraphic Division for the Sinian System of the Upper-Yangtze Region

MEI Ming-xiang1,2, NIE Rui-zhen1,2, ZHANG Hai1,2, CHEN Yong-hong1,2, MENG Xiao-qing1,2   

  1. 1State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing100083, China;
    2 School of Earth Sciences and Resources, China University of Geosciences,Beijing100083,China
  • Received:2005-09-25 Revised:2005-11-20 Online:2006-01-20 Published:2006-01-20

摘要:

上扬子区的震旦系包括陡山沱组和灯影组,前者包含较多的黑色页岩,而后者则以大套白云岩为特征。从岩相序列到米级旋回,从沉积相序列到三级层序,可将浅水台地背景的震旦系划分为5个三级层序,这些三级层序均以总体向上变浅的沉积相序列为特征;该5个三级层序组成一个二级层序,陡山沱组较多的黑色页岩到灯影组大套白云岩所组成的向上变浅序列是该二级层序的主要特点,从而表明二级层序与三级层序具有相似的相序组构。以各个主要剖面点的层序划分为基础,依据地层记录中的两种相变面和两种穿时性,可以建立研究区域震旦系层序地层格架。层序地层格架表明,包含较多的深水黑色页岩系的陡山沱组,代表了大冰期之后的海侵作用的特点;与寒武系的变化特征不同,而原生沉积组构保存较为完好的灯影组白云岩,自北西而南东沉积环境由浅变深的沉积背景中均为白云岩,这种变化特点可能意味着前寒武纪末期特殊的白云石化作用特征,同时也意味着许多有待于进一步研究的沉积学问题。

关键词: 层序划分, 震旦系, 上扬子区

Abstract:

 The Sinian System in the Upper-Yangtze region contains the Doushantuo Fm. and the Dengying Fm., the former includes more black shales and the latter is marked by a set of dolomites. From litho-facies succession to meter-scale cycle and from sedimentary-facies succession to third-order sequence, the Sinian System in the shallow-water setting can be divided into five third-order sequences that can be grouped into one second-order sequence. Thirdorder sequences are always made up of a generally upward-shoaling sedimentary-facies succession. For the second-order sequences constituted both by the Doushantuo Fm. with more black shales and the Dengying Fm. that is marked by a set of dolomites, is also an upward-shoaling facies succession.Therefore, there is similar facies-succession fabric between the third-order and the second-order sequences.According to the two types of facies-changing surfaces and two types of diachronisms in the stratigraphic, sequences-stratigraphic divisions at main logged sections become the basis to establish the sequence-stratigraphic framework of Sinian System in the study area. This sequence-stratigraphic framework indicates several features: The Doushantuo Fm. with more deep-water black shales represents a transgression process after the great glaciation period. Different from the changing feature in the Cambrian, the dolomites of the Dengying Fm. with well-preserved primary sedimentary fabrics are characterized by a set of dolomites in the deeper depositional background. This changing feature may mean a particular dolomitization in the Sinian and a problem that is further researched in the future.

Key words: sequence-stratigraphic division, the Sinian System, the Upper-Yangtze region

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