塔里木盆地西南坳陷上新统构造特征及对砂岩型铀矿的找矿启示OA

The uranium exploration work in the southwestern depression of Tarim Basin has historically focused on Jurassic and Cretaceous systems.In recent years,the nuclear industry system has successively discovered multiple significant uranium anomalies(zones)within Atushi Formation of Pliocene system,as well as revealed several benefical uranium bodies,indicating favorable prospecting potential for this stratum.Due to the relatively late initiation of uranium exploration in the Neogene system within the region,systematically studying its structural-sedimentary characteristics and analyzing its uranium mineralization potential are of great significance for guiding subsequent prospecting efforts.Based on a brief introduction to the regional geological background,the article primarily analyzed the lithofacies characteristics,geochemical features,uranium source conditions,and tectonic evolution stages of Pliocene Atushi Formation,and further examined the influence of structural differences on the distribution of target layers,sedimentary infill,hydrogeological conditions,post-magmatic alteration features,and their relationship with uranium mineralization.The results indicated that multi-stage tectonic evolution controlled the spatial distribution of sand bodies,with uranium mineralization typically occurring at locations where multiple ore-controlling factors converge.Such favorable zones were prioritized in the transition zone from braided river delta plains to the front of braided river deltas.Combined with uranium mineralization data,two uranium metaloogenic models were proposed for Pliocene Atushi Formation in the region:the oxidized zone type and the superimposed polygenetic type.It is considered that the metallogenic environment of the lower member of Atushi Formation is more favorable in Mazatag area,and the metallogenic conditions of the upper member of Atushi Formation are the best in Shache-Yecheng area.These two zones were believed the key targets for future uranium prospecting.