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Geoscience ›› 2008, Vol. 22 ›› Issue (2): 255-264.

• Engineering Geology and Environmental Geology • Previous Articles     Next Articles

Study on Sequence Stratigraphy in Clastic Rocks and Volcanics Mixing Accumulated Formation—Taking Jiamuhe Formation in the Northwestern Margin of the Junggar Basin as An Example

ZHU Yan-he1 ,YAN Yao-min2 ,WANG Ying-min1 ,ER Chuang 1 ,LI Yang-yang1   

  1. 1Faculty of Geoscience, China University of Petroleum, Beijing102249, China;
    2International Exploration and Development Corporation, SINOPEC, Beijing100083, China
  • Received:2007-11-12 Revised:2008-01-12 Online:2008-02-20 Published:2008-02-20

Abstract:

The foreland thrust belt in northwestern margin of the Junggar Basin is a significant region to research basinrange coupling and development of sedimentary system of western area of Junggar Basin. Jiamuhe Formation in Permian is mixing accumulated formation which contains volcanics, volcanoclastic and clastic rocks. Volcanics stratigraphic unit and clastic rock stratigraphic unit have the generalized origin relation, which are Smith formation and with cycles. According to the difference of lithologic character, there are clastic rock area, volcanics and clastic rock mixed area and volcanics area. In different areas, we apply different ways to find some types of unconformity surfaces generated by tectogenesis, volcanic activity or fluctuation of lakelevel and used as sequence boundaries. In clastic rocks area, unconformity surfaces in seismic profiles are represented as a truncation, a baselap, a bidirectional downlap, a toplap or an incised valley; In the mixed area, a truncation belt; while in the volcanics area, a truncation formed by relatively falling of lakelevel. So we can identify different unconformity surfaces by seismic, drilling and log data, and then divide sequences in different sedimentary environments by correlation rules based on volcanic eruption types, volcanic cycle features and sedimentary cycle features.

Key words: Junggar Basin, Jiamuhe Formation, sequence stratigraphy, volcanics, clastic rock

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