塔里木盆地喀什凹陷乌帕尔地段阿图什组下段沉积特征与铀成矿OA

The lower member of the Upper Series Artux formation in the Wupaer area,Kashgar sag,Tarim basin,serves as the main host horizon for sandstone-type uranium deposits.Investigating its sedimentary characteristics and uranium mineralization is of great significance for guiding uranium exploration in this region.Based on comprehensive analysis of field reconnaissance,core observation,and borehole data,a series of maps including isopach maps of the lower Artux formation and sand body thickness were compiled.Combined with oxidation and mineralization information revealed by boreholes and surface outcrops,the sedimentary facies and mineralization processes of the lower Artux formation were systematically analyzed.The results indicate that the sandstones in the lower Artux formation of the Wupaer area are mainly fine-to medium-grained feldspathic sandstone and feldspathic lithic sandstone.The ore-bearing host rocks contain carnotite,phosgenite,and pyrite.The study area is primarily characterized by alluvial fan and deltaic deposits.The alluvial fan facies can be subdivided into middle fan and inner fan subfacies,while the deltaic facies can be subdivided into microfacies such as deltaic plain distributary channels,deltaic plain interdistributary depressions,deltaic front subaqueous distributary channels,and deltaic front interdistributary bays.The facies transition zones between the deltaic plain distributary channels and the deltaic front subaqueous distributary channels are favorable for uranium mineralization.The uranium mineralization is evidently controlled by the interlayer oxidation zone and regional tectonics.It generally experienced stages of initial uranium enrichment,phreatic-to-interlayer oxidation transition,continuous development of the interlayer oxidation zone and uranium mineralization,and differential development.The area extending from the west of Tashdalan to Yoder,Xianazar,and southeast of Biaoerkuoyi village on the north limb of the syncline in the study area is a favorable zone for uranium mineralization,and can serve as a key target area for the next phase of sandstone-type uranium exploration in the Artux formation.