含铀砂岩中铀与有机质、油气和煤的关系——以鄂尔多斯盆地东胜地区和吐哈盆地十红滩地区为例

Aim To study the petrologic characteristics of sandstone-type uranium deposits, in Dongsheng Area of the Ordos Basin and the Shihongtan Area of the Tuha Basin, which shows that igneous and mudstone rocks in the provevance might attribute to one of the uranium resources. Methods Uranium mineralization was controlled by the oxidation-reduction interface and occurred where medium condition changed from acidic oxidation into alkaline reduction during diagenesis and epidiagenesis. Results The uplifting, tilting and exposing of the uranium-bearing beds, and hydrodynamic environment are key factors for forming interlayer oxidation zones and uranium mineralization, and sand bodies in the braided channels provided favorable space for forming interlayer oxidation zones and uranium mineralization. Favorable mudstone-sandstone-mudstone succession suite provides a good preservation for the uranium deposit. Study also shows that pitchblende coexists with pyrite in the cavities of organic fragments in uranium-bearing zones, and absorbed uranium α traces are found on the surface and around pyrite. The sandstonetype uranium deposits are distributed above and/or below the same or adjacent horizons where oil, natural gas and coal are preserved; temporally, the above energy resources basically occurred during or almost the same geological period. Conclusion Thus generation and accumulation of uranium has intrinsic relationship in origin with pyrite and organic matters.