摘要
对砂岩型铀矿而言,明确铀矿物的赋存状态及富集机理既有理论意义,又有生产实践意义。海力锦铀矿床位于松辽盆地南部,含矿层位为上白垩统姚家组下段灰色砂岩。本文通过野外地质调查,结合光学显微镜、扫描电镜、电子探针以及X-射线衍射等分析技术手段,系统阐述了该地区铀成矿的关键控矿要素、矿化类型及铀的迁移、沉淀、富集规律。研究显示,海力锦地区上白垩统姚家组多色砂体可划分为褐红色和砖红色、褐黄色和灰红色、灰白色及灰色颜色类型,分属于强氧化亚带、弱氧化亚带、过渡带(矿化带)和还原带。蚀变矿物学特征揭示,灰白色赋矿砂体中黏土矿物含量最高,主要以高岭石为主。铀矿物赋存状态研究表明,铀矿物种类以含钛铀矿物、沥青铀矿及铀石为主,呈不规则微细(网)脉或粒状发育。典型矿物研究显示,钛氧化物中存在Ti^(4+)元素的活化迁移及菱铁矿中存在Fe^(2+)元素的氧化再造现象。因此,研究区灰白色赋矿砂体可能经历过酸性还原性流体作用的影响,且区域上氧化作用动力有限,氧化作用与还原作用呈“此消彼长”耦合相关关系特征,含铀砂体持续经历氧化→还原→再氧化→再还原……的“潮汐式”成矿作用过程,铀矿物不断的被卸载‒消融‒运移‒富集,造就了海力锦铀矿床“厚度大、品位高、平米铀量高、矿化集中”独有的成矿特征。
Determination of the occurrence and enrichment mechanism of uranium in sandstone-type uranium deposits is of both theoretical and practical significance.The Hailijin uranium deposit is located in the southern part of the Songliao Basin.The ores are hosted in the gray sandstone of the lower member of the Upper Cretaceous Yaojia Formation.The sandstone of the Late Cretaceous Yaojia Formation shows different colors,including maroon and brick red,brown yellow and gray red,grayish,gray body,which may be the results of different redox conditions.The grayish ore body is rich in clay minerals composed predominantly of kaolinite.Uranium minerals are mainly titanium-bearing uranium minerals,pitchblende,and coffinite,commonly occurring as irregular micro-fine veins or grains.Mineral chemistry shows that Ti in titania and Fe in siderite were mobilized and redistributed.It can be inferred that the grayish ore body was affected by acidic reducing fluid,and is characterized by the overall weak oxidation.The relationship between oxidation and reduction has“wane and wax”feature and periodic pattern.Uranium-bearing ore body experienced prolonged alternant oxidation and reduction,which facilitated the process of unloading-dissolution-migration-enrichment of uranium.This process led to the formation of the Hailijin uranium deposit,which is characterized by the large thickness,high grade and intense mineralization.
作者
臧亚辉
姜山
李继木
宁君
张亮亮
翁海蛟
崔磊
蔺鹏飞
严兆彬
尹烁
ZANG Yahui;JIANG Shan;LI Jimu;NING Jun;ZHANG Liangliang;WENG Haijiao;CUI Lei;LIN Pengfei;YAN Zhaobin;YIN Shuo(Geologic Team No.243,CNNC,Chifeng 024000,Inner Mongolia,China;State Key Laboratory of Nuclear Resources and Environment,East China Institute of Technology,Nanchang 330013,Jiangxi,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2023年第3期546-569,共24页
Geotectonica et Metallogenia
基金
中国核工业地质局项目“内蒙古科左中旗海力锦铀矿床勘查”(202212-1)
中国核工业地质局生产中科研项目“松辽盆地南部海力锦铀矿床铀富集成因机理研究”(202212-19)联合资助。
关键词
松辽盆地
海力锦铀矿床
铀矿物
赋存状态
富集机理
Songliao Basin
Hailijin uranium deposit
uranium mineral
occurrence of uranium
enrichment mechanism
