论文部分内容阅读
相山铀矿田是我国最大的火山岩型热液铀矿田，在地质地球化学和高温高压实验研究的基础上，利用地球化学模式程序EQ3／6模拟了成矿热水溶液的形成过程和减压排泄区铀成矿作用。计算机模拟结果表明，通过大气除水与碎斑熔岩相互作用，可以形成富含F和SiO2等矿化剂的含铀热水溶液；由于铀以UO2F3和UO2(CO3)等配合物形式存在，非常稳定，即使在深部强还原环境中仍然能够迁移；酸性和碱性环境，尤其是强酸性介质有利于铀迁移；随着CO和F-含量的增高以及温度的提高，铀的迁移性能增强；在水热系统排泄区发生的降温、减压脱气（脱碳酸）和混合作用等造成铀沉淀富集，形成沥青铀矿、方柱石、萤石、方解石和赤铁矿组合，与相山矿田萤石-水云母型铀矿化特征相一致。地球化学模式程序不仅能够按天然条件模拟地球化学作用，而且还能阐明地球化学作用的反应途径和反应动力学问题，是研究铀成矿古水热系统中地球化学作用的有力手段。
Xiangshan uranium ore field is the largest volcanic hydrothermal uranium ore field in China. Based on the geochemical and high temperature and high pressure experiments, the geochemical modeling program EQ3 / 6 is used to simulate the formation process of hot metal forming solution and decompression Uranium mineralization in drainage area. Computer simulation results show that the uranium-enriched hot aqueous solution enriched with mineralizing agents such as F and SiO2 can be formed through the interaction between atmospheric dewatering and crushed lava. Because uranium is in the form of complexes such as UO2F3 and UO2 (CO3), it is very stable , Which can migrate even in deep strong reduction environment. Acid and alkaline environments, especially strong acid medium, are favorable for the migration of uranium. With the increase of CO and F-contents and the increase of temperature, the migration of uranium is enhanced. The uranium precipitation, enrichment of uranium, formation of diabase uranium, diabase, fluorite, calcite and hematite are caused by the cooling and decompression degassing (decarbonation) and mixing of thermal system drainage area, Stones - aquifer mica uranium mineralization characteristics consistent. The geochemical model program can not only simulate geochemistry under natural conditions, but also elucidate the geochemical reaction pathways and reaction kinetics, which is a powerful tool for studying the geochemical role of paleo-hydrothermal systems in uranium mineralization.