Advances in Earth Science ›› 2014, Vol. 29 ›› Issue (4): 515-522. doi: 10.11867/j.issn.1001-8166.2014.04.0515

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Evolution of the Potash-Rich Areas in Evaporation Basin during the Epigenetic Stage with Continental Block Being Active

Chen Kegui 1, Li Li 1, Li Chunmei 2, Yu Jing 3, Wang Lin 4, Lin Xin 4   

  1. 1. School of Earth Science and Technology, Southwest Petroleum University, Chengdu 610500, China;
    2. Research Institute, Bureau of Geophysics Prospecting, Zhuozhou 072750, China;
    3. Research Institute of Exploration and Development, Xinjiang Oilfield Company, Karamay 834000, China;
    4. International Division, China Petroleum Logging CO. LTD, Beijing 102200, China
  • Received:2014-01-14 Online:2014-04-10 Published:2014-04-10

Chen Kegui, Li Li, Li Chunmei, Yu Jing, Wang Lin, Lin Xin. Evolution of the Potash-Rich Areas in Evaporation Basin during the Epigenetic Stage with Continental Block Being Active[J]. Advances in Earth Science, 2014, 29(4): 515-522.

Based on analysis of potash-forming background in the Sichuan Basin, the theory of “source control” for potash is proposed. The so-called source areas are referred to those sinking centers meeting the conditions of forming potash early while the potassium-rich areas are probably not the early potassium’s sedimentary centers and after migrating along with brine potassium possibly would deposit in the edge of the depression where formation’s pressure is relatively low. During the diagenesis stage, the sedimentary center increasingly subsided, resulting in larger depositional thickness, greater remaining pressure of potassium reservoir and higher temperature of formation. Under such conditions, the potash’s solubility increases so much that potash’s solution is prior to its accumulation in the deep depression’s center. Drived by the compaction force, the potassium-rich water in the sedimentary rock would flow from the center to the edge of depression. At last, the potassium-rich water would migrate to those areas with lower pressure, then precipitate and accumulate so as to develop potash deposit. In this paper, the ore-forming characteristics of both the Triassic Nanchong salt basin polyhalite and the Pingluo Dam potassium-rich brine in Sichuan Basin are taken as examples for further detailed discussion.

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