世界核地质科学2025，Vol.42Issue(5)：1003-1019,17.DOI:10.3969/j.issn.1672-0636.2025.05.008
银额盆地居延海坳陷苦泉沟组砂岩水文地球化学与铀溶解沉淀特征
Hydrogeochemistry and uranium dissolution-precipitation characteristics of sandstone in Kuquangou formation of Juyanhai depression,Yingen-Ejin basin
摘要
Abstract
Uranium is an important strategic resource,and its mineralization process is closely related to hydrogeochemical conditions.Groundwater in the sandstone of Kuquangou formation in Juyanhai depression of Yingen-Ejin basin was studied in this paper by discussing the hydrogeochemical characteristics of uranium mineralization through field investigation,water chemical composition analysis and PHREEQC software simulation.The results showed that the shallow groundwater of Kuquangou formation is neutral to weakly alkaline(pH 7.46～8.47)and was in a weak oxidation environment(Eh 43～137.8 mV)overall.The hydrochemical type is mainly SO4·HCO3-Mg·Na,and the chemical composition is mainly controlled by silicate rock weathering.Uranium in water mainly existed in the forms of UO2(CO3)34-(proportion＞85%)and UO2(CO3)22-(proportion 5%～10%).The saturation index(SI)of pitchblende is less than 0,indicating that uranium is in a dissolved state.The Eh boundary value of uranium mineralization was-66.38～-43.55 mV,which is lower than the actual Eh value.The uranium concentration in groundwater(7.16～23.21 μg·L-1)was much lower than the threshold required for precipitation(1.33～186.11 mg·L-1).The water-rock system experiment of core showed that the specific reducing environment and uranium concentration conditions formed by water-rock balance could make SI greater than 0,Eh reaction condition index(RCIEh)less than 0,and the actual uranium concentration higher than the precipitation concentration boundary value,resulting in obvious precipitation and enrichment of uranium.The study revealed that the high oxidizability and low uranium concentration of shallow groundwater were the core restricting factors for uranium enrichment and mineralization,while the deep reducing environment could produce the hydrogeochemical conditions for uranium precipitation.关键词
铀成矿/水文地球化学/苦泉沟组砂岩/居延海坳陷Key words
uranium mineralization/hydrogeochemistry/sandstone of Kuquangou formation/Juyanhai depression分类
天文与地球科学引用本文复制引用
刘苏鹏,刘金辉,刘武生,牛霆,贾立城,何大鹏,刘勇毅,何挺..银额盆地居延海坳陷苦泉沟组砂岩水文地球化学与铀溶解沉淀特征[J].世界核地质科学,2025,42(5):1003-1019,17.基金项目
核技术研发项目(编号:地H2401)资助 Supported by the Scientific Research Project of Nuclear Technology R&D(No.地 H2401) （编号:地H2401）
