中文摘要:利用热力学方法计算了两秦岭铀矿床含矿热液中铀的迁移形式。结果表明,从含矿热液早阶段到主成矿作用发生之前,热液中的铀主要以[UO2(CO3)0]形式迁移;在晚阶段残余热液中,铀的迁移形式改变为以[UO2 (SO40]为主。铀迁移形式改变的原因与大气降水中SO42-离子的大量带入有关,表明含矿热液来自深部而非大气降水。
Abstract:This paper has analysed constituents of fluid inclusions in quartz and calcite formed at different stages of uranium-bearing hydrothermal solution in the West Qinling uranium field and, using thermodynamic method, calculated migration forms of uranium in uranium-bearing hydrothermal solution. The results show that at the early ore-forming stage, the uranium-bearing hydrothermal solution, mainly contains K+, Na+, Ca2+, Mg2+, Cl-, CH4, CO32- and CO2, and is deficient in SO42-, and at the middle and late ore-forming stages, with the elevation of the emplacement of uranium-bearing hydrothermal solution and the variation of the environment, K+ and Cl- tend to decrease, Na+ somewhat increases, and Ca2+, Mg2+, CH4, CO32-, CO2 and SO42- obviously increase. The mixing of the groundwater with the uranium-bearing hydrothermal solution, as evidenced by the fact that the groundwater at the oxidation-reduction interface is of SO42--HCO3 --Ca2+ and Mg2+ types, and the water body is rich in Ca2+, Mg2+ and SO42- ions. Thermodynamic calculation of uranium migration forms in uranium-bearing hydrothermal solution demonstrates that at the early and middle ore-forming stages uranium in the uranium-bearing hydrothermal solution migrates mainly in the form of [UO2(CO3)0], whereas in the residual hydrothermal solution of the late stage, the migration form of [UO2 (SO40] becomes dominant. It is therefore inferred that the change of uranium migration forms might be attributed to the entry of large quantities of SO42- ions derived from meteoric water, and that the uranium-bearing hydrothermal solution is derived from the depth instead of from meteoric water.
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基金项目:地质矿产部“八五”定向攻关项目(9301)
引用文本:
何明友.1997.西秦岭铀矿床铀迁移形式的热力学研究[J].矿床地质,16(2):181~188.1997.Thermodynamic study of Uranium migration forms in the west Qinling Uranium field[J].Mineral Deposits16(2):181~188
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