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Uranium, as one of twenty–six kinds of important minerals in China, is strategic resource and energy mineral, which has been thoroughly investigated in the project of National Potential Evaluation of Uranium Resource. During the implementation of this project, the authors summarized the metallogenic regularity of uranium resource in China systematically, through the researches of geological characteristics of uranium resource, uranium deposits type (genetic and prediction type), temporal and spatial distribution, and metallogenic series. Based on the investigation of present situation and progress in uranium exploration, this paper proposes the uranium deposits in China should be divided into 4 classes, 9 types, 21 subtypes in genetic, and 50 types in prediction; suggests to divide China into 29 uranium metallogenic belts and 20 uranium prospective area, and constructs 20 uranium polymetallic metallogenic series, through summarizing temporal and spatial distribution characteristics and metallogenic regularity of uranium deposits in China. The above research is beneficial to the comprehensive understanding of regional uranium metallogenic regularity, and will direct the uranium exploration in the future.

In adjustment to fulfill the requirements of the investigation regarding the lower Cretaceous sandstone uranium deposit in the Naogaodai area within the northwest of Ordos Basin, twenty-seven sandstone samples obtained from the Lower Cretaceous Huanhe Formation were analyzed for major, trace and rare earth elements (REE). The source of clastic and tectonic background was additionally analyzed. The results show that Huanhe sandstone is feldspar rich sandstone, and also the mineral composition is principally quartz, albite and plagioclase; the ratio of light to heavy rare earth elements (LREE/HREE) is 9.25–10.83, with an average value of 10.00; (La/Yb)CN is 10.20–12.53, with an average value of 11.24, demonstrating that LREE is enriched and fractionated compared with HREE. REE distribution patterns are similar, which additionally reveals that Huanhe sandstone has a homogenous source; the Index of Compositional Variability (ICV) value is 1.17–1.73, with an average value of 1.35, both greater than 1, showing an immature property, which may be first-order cycle deposition. The average value of the Chemical Index of Alteration (CIA) is 50.29, suggesting that the source rock has encountered weak chemical weathering; sandstones are near-source first-cycle provenance, which is not significantly influenced by sedimentary sorting and recycling. The geochemical qualities further indicate that Huanhe sandstone was deposited in a passive margin and experienced moderate weathering.