中国北西部地区地浸砂岩型铀矿床成矿条件,分布规律与找矿方向

本文从中国北西部地区实际地质情况出发，着重阐明了区域中新生代盆地地浸砂岩型铀矿床形成的铀源条件、含铀建造的形成与分布、盆地类型与结构及富铀性对形成地浸砂岩型铀矿的影响；并以区内已有层间氧化带地浸砂岩型铀矿床为例，论述了砂岩型铀矿床形成的岩相古地理条件及对铀成矿的控制作用、盆地古水文地质与层间氧化带发育条件及对铀成矿的影响；同时，从含铀盆地的区域大地构造位置、岩相古地理条件、含矿主岩的地层时代和铀成矿时代及水文地质条件等四方面阐述了本区层间氧化带地浸砂岩型铀矿床分布规律与找矿方向。

MINEROGENETIC CONDITIONS, DISTRIBUTION LAWS AND PROSPECTING DIRECTIONS FOR IN-SITU LEACHABLE SANDSTONE-TYPE URANIUM DEPOSITS IN NORTHWESTERN CHINA

On the basis of geologic conditions of the northwestern part of China,this paper emphatically expounds uranium source conditions for the formation of in-situ leachable sandstonetype uranium deposits, the formation and distribution of uranium-bearing formations inMeso-Cenozoic basins in this region,and the influence of basin types,structure and uraniumfertility on the formation of in-situ leachable sandstone-type uranium deposits. And takingthose known deposits of interlayer oxidation zones in the region as examples,it deals with thelithofacies and palaeogeography conditions for the formation of the sandstone-type uraniumdeposits and their control on uranium ore-formation,the influence of the palaeohydrogeologyand the development conditions of interlayer oxidation zones in the basin on the formation ofuranium deposits. In the meantime,the distributution laws and the prospecting directions ofin-situ leachable sandstone-type uranium deposits of interlayer oxidation zone in this regionhas been expounded in the following four aspects:the regional geotectonic location of the uranium-bearing basin llithofacies and palaeogeography conditions;the ages of ore--hosting layersand uranium mineralization;and the hydrogeological conditions.