沁水盆地西南部上古生界砂岩型铀矿关键控矿因素OA

[Objective]Industrial sandstone-type uranium mineralization has been discovered in the Upper Permian of the southwestern Qinshui Basin.This stratigraphic horizon is among the oldest industrial uranium-bearing rock sequences in China,boasting significant exploration potential.[Methods]Through core observation,sedimentological mapping,scanning electron microscopy(SEM)analysis,and other experimental testing methods,the occurrence characteristics,distribution patterns,and key controlling factors of uranium mineralization have been investigated.[Results]The uranium mineralization occurs in gray to dark gray fine-grained sandstones of the Lower Member of the Upper Permian Shiqianfeng Formation.The cumulative thickness of mineralized sandbodies reaches a maximum of 7.85 meters,with the highest uranium grade of 0.0275％.Planar distribution of uranium orebodies is predominantly in an isolated island-like pattern,and the main uranium mineral types are uraninite and pitchblende.Uranium minerals are frequently found associated with quartz,feldspar,clay minerals,and pyrite.Uranium mineralization is primarily controlled by the distribution of uranium reservoirs,reducing geological bodies,and interlayer oxidation zones.[Conclusions]It is mainly distributed in areas with the following characteristics:sandbody thickness ranging from 20 to 60 meters,sand content between 30％and 60％,sandbody bifurcation and thinning zones,mudstone thickness of 40 to 80 meters,and transition zones within interlayer oxidation zones.The research results provide insights into regional uranium mineralization processes and point out the direction for further uranium exploration.