鄂尔多斯盆地北部下白垩统铀成矿模式  

Uranium metallogenic model of the Lower Cretaceous in the northern Ordos Basin

作　　者：王龙辉 剡鹏兵 焦养泉[2] 吴立群[2] 张字龙[3] 荣辉[2] 张帆[2] 李振成 钟伟辉 Wang Longhui;Yan Pengbing;Jiao Yangquan;Wu Liqun;Zhang Zilong;Rong Hui;Zhang Fan;Li Zhencheng;Zhong Weihui(CNNC Geologic Party No.208,Baotou Inner Mongolia 014010,China;China University of Geosciences(Wuhan),Wuhan 430074,China;Beijing Research Institute of Uranium Geology,Beijing 100000,China)

机构地区：[1]核工业二○八大队,内蒙古包头014010 [2]中国地质大学(武汉),武汉430074 [3]核工业北京地质研究院,北京100000

出　　处：《地质科技通报》2023年第3期222-233,共12页Bulletin of Geological Science and Technology

基　　金：中国核工业部地质局项目“鄂尔多斯盆地北部铀矿资源调查评价与勘查”(201902)。

摘　　要：自2019年以来,鄂尔多斯盆地北部下白垩统找矿获得重大突破,下白垩统有望成为继中侏罗统之后又一重要的砂岩型铀矿找矿目的层,建立下白垩统的成矿模式能够更好地指导找矿工作。基于前人的区域地质资料和现有的钻探与测试资料,对该区下白垩统铀成矿基本地质特征进行了系统总结,并初步构建了下白垩统的铀成矿模式。研究表明:现有的6种岩石类型可划分为3类地球化学类型,铀矿化主要富集于褐色、褐红色砂岩向绿色砂岩过渡的褐灰色砂岩中,绿色砂岩为先氧化后还原形成;下白垩统的铀成矿类型以层间氧化作用为主、潜水氧化作用为辅,成矿年龄主要为晚白垩世;下白垩统的铀成矿模式为“二次氧化”成矿模式,分为3个期次:一次氧化成矿期、大规模还原期和二次氧化成矿期。研究结果可以为鄂尔多斯盆地新层位的铀矿勘查提供参考。Since 2019,major breakthroughs have been made in the prospecting of the Lower Cretaceous sandstone-type uranium deposits in the northern Ordos Basin.The Lower Cretaceous sandstone layer is expected to become another important sandstone-type uranium prospecting target after the Middle Jurassic.Establishing the metallogenic model of the Lower Cretaceous provides a better guide for prospecting work.Based on previous regional geological,drilling cores,and analytical data,the authors systematically summarized the basic geological characteristics of uranium mineralization in the Lower Cretaceous in this area and preliminarily established the uranium metallogenic model of the Lower Cretaceous.The results suggest the six Lower Cretaceous rock types can be divided into three geochemical types.Uranium mineralization mainly occurs in the brown-gray sandstone,which is the transition zone from brown-red sandstone to green sandstone.The green sandstone is formed by oxidation first and then reduction.The metallogenic type is dominated by interlayer oxidation,supplemented by phreatic oxidation in the Late Cretaceous.The Lower Cretaceous"secondary oxidation"uranium metallogenic model can be divided into three stages:first oxidation mineralization stage,large-scale reduction mineralization stage,and second oxidation mineralization stage.These research results can provide a new idea for uranium exploration in new strata of Ordos Basin.

关 键 词：成矿模式 砂岩型铀矿 下白垩统 鄂尔多斯盆地北部 

分 类 号：P619.14[天文地球—矿床学]