302铀矿床成矿物理化学条件、热液来源和运移方向 |
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引用本文:.1990.The physicochemical conditions for metallogenesis of no. 302 uranium deposit and the source and migration direction of its hydrothermal[J].Mineral Deposits,9(2):149~157 |
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中文摘要:流体包裹体研究表明,302铀矿床成矿温度210℃左右。矿化在温度降低的过程中发生。成矿期热液的盐度(平均3.02 wt.%)相对矿后期(平均2.55 wt.%)偏高,而密度(平均0.809/cm3)相对矿后期(平均0.909/cm3)偏低。热液压力不大,变化在5—30 MPa之间。成矿热液富含CO2和CH4,为弱碱性(pH=6.97)Ca2+ - Na+ - K+/Cl- - HCO3- - F-型富铀(2.2×10-3mol)热液,铀呈UO2(CO)22-的形式运移。氧同位素分析表明,成矿热液来源于大气降水。温度和浓度的空间变化显示热液由南向北、由深部向上部运移,Fs为导矿构造,与其相交的近南北向构造储矿。 |
中文关键词:物理化学条件 热液来源 运移方向 302铀矿床 |
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The physicochemical conditions for metallogenesis of no. 302 uranium deposit and the source and migration direction of its hydrothermal |
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Abstract:Fluid inclusion studies show that the ore-forming temperature for No.302 uranium deposit Was 210℃ or so, and the uranium mineralization took place during the decreasing in temperature. The salinity of hydrothermal solution at the ore-forming stage(3.02 wt.% on the average) was higher than that at the post-ore stage (2.55 wt.% on the average); nevertheless, the density of hydrothermal solution at the ore-forming stage(0.80 g/cm3 on the average) was lower than that at the post-ore stage(0.90g/cm3 on the average). The ore-forming pressure was small, ranging from 5 to 30 MPa. The gases of the hydrothermal solution at the ore-forming stage comprised mainly CO2 and CH4. In composition, the uranium-bearing hydrother-real solution(U content = 2.2×10-3 mol) was weakly alkaline (pH=6.97) and of Ca2+ - Na+ - K+/Cl- - HCO3- - F- type. Uranium is considered to have migrated in the form of UO2(CO3)32-. Oxygen isotope analyses show that the hydrothermal solution of the ore-forming stage was deI’ived from the meteotic water. According to spatial variations in temperatures and salinities of the hydrothermai solution it is believed that the solution migrated from the southem deeper part to tile northern shallower part along No.9 fault which served as all ore-conduit structure. The ores were deposited in the NS-trending fractures cut by No.6 fault. |
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