鄂尔多斯盆地东北缘纳岭沟东-皂火壕成矿区铀成矿特征和成矿机理分析  

Uranium Metallogenic Characteristics and Mechanism of Nalinggou East-Zaohuohao Area on the Northeast Margin of Ordos Basin

作　　者：刘正义[1] 李西得[1] 黄钢 刘红旭[1] 王明太[1] 惠小朝[1] LIU Zheng-yi;LI Xi-de;HUANG Gang;LIU Hong-xu;WANG Ming-tai;HUI Xiao-chao(Beijing Research Institute of Uranium Geology,Beijing 100029,China;Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中国地质科学院,北京100037

出　　处：《东华理工大学学报（自然科学版）》2020年第5期417-429,共13页Journal of East China University of Technology(Natural Science)

基　　金：中核集团集中研发项目“鄂尔多斯盆地北部砂岩型铀矿关键因素识别与靶区优选”(地LTD1601-2)。

摘　　要：经野外钻孔岩芯编录及其标本肉眼观察、室内图件综合和镜下鉴定,并配合扫描电镜、电子探针以及主量、微量元素、有机碳和铀、钍同位素234U/238U、230Th/232Th比值、烃类等各种分析,考虑矿物的衍射和黏土矿物种属分量和总量,V/(V+Ni)、Th/U、(K+I)/(C+S)、87Sr/86Sr和铀、钍同位素、烃类对比,以及常温常压下样品浸液pH、ΔEh测试结果,对鄂尔多斯盆地东北部盆地边缘纳岭沟东—皂火壕成矿区含铀系岩石沉积环境以及对铀成矿特征和成矿机理加以讨论。研究结果表明,含矿岩系及围岩形成于不同的沉积环境,其中氧化-还原过渡带是该区砂岩型铀矿主要成矿部位;延安组顶部地层存在长期沉积间断及古气候演化对该区铀成矿具有积极意义,同生沉积成岩成矿预富集为该区铀成矿提供了基础;构造作用下盆地隆升剥蚀,含矿围岩发生碳酸盐化、钾长石化等碱交代,围岩褪色,为铀矿的再富集提供了物质来源。Nalinggou east-Zaohuohao metallogenic area is located in northeast margin of Ordos basin.A lot of work has been done on drilling core logging,hand specimen examination,microscopic study,SEM and geochemical analysis of study area.The analysis include major and trace elements,organic carbon,hydrocarbon,uranium and thorium isotope,the Ph and Eh of samples immersion fluid in normal temperature and pressure.Based on comparative study of mineral diffraction,clay minerals content,the ratio of V/(V+Ni),Th/U,(K+I)/(C+S),87Sr/86Sr,uranium and thorium isotope,and hydrocarbon between different rocks,the sedimentary environment,uranium mineralization characteristics and metallogenic mechanism of uranium rocks have been discussed.The results show that the ore-bearing rock and wall rock were all formed in different depositional environment,and redox transitional zone may be the most favorable place for uranium prospecting.The paleo-climate variation and long-term depositional breaks existed in the upper Yan'an formation have positive significance for the uranium mineralization in this area,and the diagenesis and mineralization of different rock in syn-depositional stage are all favorable to uranium enrichment.The uplifting and erosion of the basin,and alkali metasomatism of wall rock such as carbonation and potash feldspathization were important material source of uranium mineralization.

关 键 词：鄂尔多斯盆地 纳岭沟东-皂火壕 成矿区 铀成矿特征 成矿机理 

分 类 号：P619.14[天文地球—矿床学]