Advances in Earth Science ›› 2012, Vol. 27 ›› Issue (10): 1054-1060. doi: 10.11867/j.issn.1001-8166.2012.10.1054
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Zhang Chengjiang,Xu Zhengqi, Ni Shijun, Yin Guan
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Zhang Chengjiang,Xu Zhengqi, Ni Shijun, Yin Guan. Genesis of Potassiumbearing Brine in Pingluoba Structure Region, Western Sichuan Depression[J]. Advances in Earth Science, 2012, 27(10): 1054-1060.
With many subordinate useful components, such as boron, bromine, iodine and lithium, the Pingluoba structure region in Western Sichuan Depression is presently the highest concentration in Potassium ion of all the deep marine carbonate strata discovered in China. Since their discovery in the early 1990s at Well Pingluo 4, there are multiple viewpoints to the genesis of potassium-bearing brine. The chief argument is that the potassium-bearing brine is formed through sedimentarymetamorphism in the primary seawater. Some phenomena that cannot be fully explained by the sedimentarymetamorphic theory, have been discovered by the author in the study recently. Therefore, the paper traces the sources of both the solvent (water) and the solute of the brine during the study. Then, the author proposes the conclusions about the multi-source, multi-stage genesis of the potassium-bearing brine in Sichuan basin.① The source of solvent of the brine is related to ancient seawater and the dehydration process of hydrous minerals. According to its genetic characteristics of multi-source and multi-stage, the potassium in brine is mainly related to the concentration of primary seawater, and secondarily the dissolution of potassiumbearing minerals, as well as the Permian basalt, the Triassic green pisolites and some deep fluid activities. ② According to the study result, a genetic model of the potassium-bearing brine in Pingluoba structure region is presented. The gypsum-salt basin is the foundation of the potassium-bearing brine; the fracture constitutes the main channel; the carbonate strata, which lies between the gypsum-salt stratum, forms good reservoir; the fractures and pores are the main reservoir space; the structural highs are the effective storage sites; temperature is the important controlling factor for ore grade; and the gypsum-salt stratum of high thickness are the important secure protection for the preservation of the potassium-bearing brine.