鄂尔多斯盆地西南部白垩系砂岩型铀矿矿化特征及分带性研究  

Study of the Characteristics and Zonation of Sandstone Hosted Uranium Mineralization in Cretaceous of Southwestern Ordos Basin

作　　者：林锦荣[1] 李子颖[1] 衣龙升[1] 贺锋[1] 武正乾 刘政国 邱林飞[1] 李西得[1] 刘坤鹏 刘持恒 郭健 王君贤 LIN Jinrong;LI Ziying;YI Longsheng;HE Feng;WU Zhengqian;LIU Zhengguo;QIU Linfei;LI Xide;LIU Kunpeng;LIU Chiheng;GUO Jian;WANG Junxian(CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China;Research Institute No.203,CNNC,Xi’an,Shanxi 710086,China)

机构地区：[1]核工业北京地质研究院中核集团铀资源勘查与评价技术重点实验室,北京100029 [2]核工业二〇三研究所,陕西西安710086

出　　处：《铀矿地质》2023年第6期904-918,共15页Uranium Geology

基　　金：中核集团“第四代铀矿勘查关键技术研究与示范(第一阶段)”项目“基于大数据的砂岩型铀矿三维预测技术研究”(编号:地SD04);“砂岩型铀矿多重耦合地质成矿作用与时空定位”(编号:中核科发2021-143);中核集团青年英才项目“鄂尔多斯盆地西南部下白垩统厚大灰绿色砂体对铀成矿制约关系”(编号:地QNYC2301)联合资助。

摘　　要：文章通过鄂尔多斯盆地西南部白垩系砂岩型铀矿成矿特征研究,识别并划分了砂岩型铀矿矿石类型,把鄂尔多斯盆地西南部白垩系砂岩型铀矿划分为灰色砂岩型铀矿、灰黑色有机质砂岩型铀矿、红色砂岩型铀矿、黄色砂岩型铀矿4种矿石类型,总结了砂岩型铀矿矿化特征。铀矿化具有垂向分带性,自下而上划分为灰色砂岩铀矿化带、黄色砂岩铀矿化带、红色砂岩铀矿化带、灰黑色有机质斑团铀矿化带、灰黑色有机质脉体铀矿化带5个铀矿化带,总结了不同铀矿化带的铀矿化蚀变矿物组合、铀矿物组合、相关元素含量特征,从深部到浅部还原成矿作用由强到弱,铀主要富集在下部灰色砂岩铀矿化带,有机质(碳质)主要富集在上部灰黑色有机质斑团、脉体铀矿化带。认为鄂尔多斯盆地西南部白垩系不同矿石类型铀矿化特征相似,均为深部有机成矿流体渗出还原、富集成矿的产物,具有渗出成因铀矿成矿特征。This paper studied the mineralization characteristics of sandstone hosted uranium mineralization in the Lower Cretaceous of southwestern Ordos Basin and four type uranium ore have been identified:i.e.,gray sandstone ores,dark gray organic-bearing sandstone ores,red sandstone ores as well as yellow sandstone ores.The distribution feature of uranium mineralization were summarized in depth.Vertically,the uranium mineralization can be divided into 5 zones from lower to upper,gray sandstone mineralization zone,yellow sandstone mineralization zone,red sandstone mineralization zone,zone of dark gray sandstone with organic dissemination,and zone of dark gray sandstone with organic veins.Alteration mineral combination,uranium mineral assemblages,and geochemical composition have been studied for different mineralization zones.It was concluded that from the deep to the surface,reductive activity decreases,and uranium is mainly concentrated in the gray zone in deep,while organic matters are mainly concentrated in the upper dark gray zone as dissemination or veins.It was believed that in southwestern Ordos Basin,different types of uranium ores in Cretaceous strata bear similar uranium mineralization features,and they were all resulted from deep organic-bearing fluids exudation,reduction and the enrichment of uranium,therefore,different types of uranium mineralization may be formed in the process of exudative metallogenesis.

关 键 词：有机质 垂向分带性 有机成矿流体 渗出成因 白垩系砂岩型铀矿 

分 类 号：P619.14[天文地球—矿床学]