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Geoscience ›› 2018, Vol. 32 ›› Issue (02): 227-239.DOI: 10.19657/j.geoscience.1000-8527.2018.02.02

• Sedimentology • Previous Articles     Next Articles

Analysis of the Sedimentary Environment in the North of Dongpu Depression During the Deposition of the Middle Section of the Third Member of the Shahejie Formation

LI Bei1(), LIU Chiyang1(), HUANG Lei1, JIANG Feihu2, GUO Pei1, LU Kun2   

  1. 1. State Key Laboratory of Continental Dynamics, Northwest University, Xi’an, Shaanxi 710069, China
    2. Research Institute of Exploration & Development, Zhongyuan Oilfield Company, SINOPEC,Puyang, Henan 457001, China
  • Received:2017-06-01 Revised:2017-10-24 Online:2018-04-10 Published:2018-05-07

Abstract:

The salt rocks and source rocks are extensively developed in the middle section of the third Member of Shahejie Formation in the North of Dongpu Depression and the two seemingly coexisting substances are intermixed here. In this period, the sedimentary characteristics of the study area were the continuous deposition of multi-salt rhythm and multi-layer hydrocarbon source rocks. Individual salt rhythms vary in thickness from a few meters to more than ten meters, the hydrocarbon source rocks have high organic matter abundance and the type is good. In the plane, the two are symbiotic with the sedimentation center of the lake basin, and in the vertical, high organic matter abundance, good kerogen type and high salinity formation have a better correspondence.Therefore, it has become an important research object for the restoration of paleoclimate and paleoenvironment. We studied the sedimentary environment of the middle section of the third Member of Shahejie Formation in the North of Dongpu Depression through petrology, paleontology, and the methods of Sr/Ba,B/Ga,(V+Ni+Mn),Fe/Mn,Sr/Cu,Mg/Ca,V/(V+Ni),as well as REE content and chlorine isotope. The results showed that the sedimentary environment of the middle section of the third Member of Shahejie Formation in the North of Depression was the reduction environment of the deep-water deposition, and the ancient salinity was a little high,which is semi-saltwater-saltwater deposition. The trace elements and the spore fossils indicate the environment of the middle section of the third Member of Shahejie Formation in the study area was warm and humid.

Key words: Dongpu depression, the middle section of the third Member of Shahejie Formation, sedimentary environment, paleosalinity, paleoclimate, paleo-water-depth, redox property

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