Sedimentary Characteristics and Uranium Metallogenic Conditions of Zhiluo Formation in Xinhua Area,Ning County,Southern Ordos Basin
Xinhua area is one of the key areas for prospecting in the Middle Jurassic Zhiluo Formation in the southern Ordos Basin,the sedimentary characteristics and uranium metallogenic conditions play important role in guiding the exploration of sandstone type uranium deposits in this area.Based on core observation and comprehensive analysis of the drilling data,a series of maps such as thickness of Zhiluo Formation,sand body thickness and percentage,oxidation rate and uranium mineralization prospect prediction map,the sedimentary facies and uranium metallogenic conditions of Zhiluo Formation were analyzed comprehensively as well.The result showed that:the upper member of Zhiluo Formation in Xinhua area are mainly the sediments of meander river faces,which can be divided into meander river channel,side beach,natural bank and flood plain microfacies deposits,while the lower member of Zhiluo Formation are mainly the products of braided river deposition,which can be divided into braided river channel,channel bar and flood plain microfacies deposits.Among the developed faces,the braided river channel sand body of the lower member of Zhiluo Formation has moderate thickness,good connectivity and rich in reducing substances,which is favorable for uranoium mineralization.In Xinhua area,there are structural skylights and interlayer oxidation zones.The braided river channel in the lower part of Zhiluo Formation is distributed from south to north,and the oxidation zone and sand body distribution are basically the same,which is favorable to uranium mineralization.Based on the structural conditions,sedimentary characteristics,epigenesis alteration characteristics and uranium mineralization information,natural gamma anomalies,it was believed that the Zhaocun-Baidian-Cuijialing area is the most favorable area for uranium mineralization,and should be the key target area for the next exploration of sandstone type uranium deposits in Zhiluo Formation.
sedimentary faciesZhiluo Formationsouthern Ordos Basinsandstone type uranium depositmetallogenic condition