中文摘要：

地浸砂岩型铀矿床是一种具有重要经济价值的铀矿类型，受到世界各国地质勘探部门的高度关注。近年来，鄂尔多斯盆地在石油和天然气勘查取得重大进展的同时，于盆地东胜地区也发现大规模地浸砂岩型铀矿床，标志着中国该类型铀矿勘查取得重要突破。该文应用地球化学综合分析研究，获得成矿流体的温度、盐度条件和同位素地球化学参数。含铀砂岩中碳酸盐胶结物C-O同位素测试结果表明，胶结物中的碳属于地幔碳、生物有机体和沉积的碳酸盐混合成因。通过流体包裹体H-O同位素分析，表明成矿流体可能是原生的岩浆水上涌和大气降水混合形成的建造水，其中一部分有机质加入到成矿作用中来，这对于铀的还原具有重要的意义。结合盆地的演化特点，建立了这种砂岩型铀矿的成矿地球化学模型。笔者认为，其铀矿的形成机制可以分为两个过程，一是氧化过程，二是还原过程，成矿过程伴随各种微量元素和气液相分子的氧化、还原和迁移过程。该成矿模型的建立对认识盆地铀矿质的沉淀和富集规律以及在类似盆地寻找此类铀矿床，具有理论和现实意义。

英文摘要：

The in-situ leaching sandstone-type uranium deposit is one of the uranium deposits with important industrial values, and the main target of exploration in Chinese nuclear geology. With the development of oil and natural gas exploration in the Ordos basin, a breakthrough in exploration of in-situ leaching sandstone-type uranium deposit in the northern part of the basin has been achieved. After a brief introduction to the metallogenic geological conditions of this type of uranium deposit in Ordos basin, we provide the temperature and salinity conditions as well as the isotopic geochemical parameters of the ore-forming fluid, which are obtained by the comprehensive geochemical analyses. The hydrogen and oxygen isotopic analyses of fluid inclusions indicate that the fluid as the formation water was derived from the mixture of magmatic water and meteoric water. The carbon and oxygen stable isotopic analyses of cements of U-bearing sandstones show that the genesis of carbonate cements was the mixtures of mantle carbon, organic carbon and sedimentary carbon. This information presents the evidence that the organic material did come into the ore-forming process, which is of significance to the formation of in-situ leaching sandstone-type uranium deposit. The ore-forming geochemical model for this type o of uranium deposit has been established. The uranium ore-forming processes include oxidizing and reducing processes, during which some elements are enriched and some are depleted, accompanied with the uranium migration. This study is of significance for understanding the enrichment and sedimentation of uranium as well as for finding the similar types of uranium deposits in other related basins.