湘西北晓坪坳陷黑色岩系铀多金属矿物赋存特征及指示意义  

Mineral Occurrence Feature and Its Indicating Significance of Uraniumpolymetallic Bearing Black Rock Series in Xiaoping Depression Northwestern Hunan

作　　者：王健[1] 王文全[1] 漆富成[1] 王振云[1] 张文东 WANG Jian;WANG Wenquan;QI Fucheng;WANG Zhenyun;ZHANG Wendong(CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,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

出　　处：《铀矿地质》2022年第5期940-948,共9页Uranium Geology

基　　金：中国核工业地质局地勘费项目“湘桂黔黑色岩系铀多金属成矿条件与成矿远景预测研究”(编号:地D2104)和“浅表开放体系铀成矿作用模拟实验研究”(编号:202002-4)联合资助

摘　　要：湘西北晓坪坳陷位于湘西北铀多金属成矿带的北部,是整个成矿带上有用元素种类和矿物类型最为丰富的地区,通过对研究区系统的采样分析,结果表明,主要的矿化元素中U含量介于(1.50~210.30)×10^(-6)、V含量变化范围为(26.32~17812.13)×10^(-6)、Ni含量变化范围为(18.32~6634.10)×10^(-6)、Mo含量变化范围为(2.70~12406.41)×10^(-6),与上地壳相比,这几种主要的矿化元素浓集系数,均达到了几十倍至上千倍。通过电镜观察和探针测点发现晓坪坳陷中发现的铀矿物以晶质铀矿和沥青铀矿为主,铀石相对较少,Ni主要以含镍黄铁矿、辉砷镍矿等独立的矿物形式存在,Mo主要以胶硫钼矿的形式存在,V主要以黏土吸附和类质同象形式存在,没有发现钒的独立矿物,同时发现少量方铅矿和闪锌矿。在晶质铀矿和铀石中发现了元素Y,在赋矿岩石气泡孔洞中发现晶质铀矿+辉砷镍矿+闪锌矿的高温矿物组合,以上发现指示晓坪坳陷黑色岩系成矿作用,与海底喷流过程中不断上涌的深源高温含矿热水关系密切。统计发现晓坪坳陷黑色岩系矿物赋存位置可以分为气泡孔洞、溶蚀孔洞、沉积物裂隙、矿物间隙四种类型,其中最主要的矿物赋存位置为气泡孔洞和溶蚀孔洞。Xiaoping depression is located in the north of northwestern Hunan uranium-polymetallic metallogenic belt and is the most abundant area of useful elements and minerals in the whole metallogenic belt.Systematic sampling and assay showed that among the main mineralizing elements,U is between 1.50×10^(-6)to 210.30×10^(-6),V is between 26.32×10^(-6)to 17812.13×10^(-6),Ni is between 18.32×10^(-6)to 6634.10×10^(-6),Mo is between 2.70×10^(-6)to 12406.41×10^(-6).Compared to upper crust,these mineralization elements have enriched from dozens to thousands times.The uranium minerals were found to be uraninite and pitchblende by SEM and EPMA,and some ffinite was also discovered,Ni mostly in the form of pentlandite and gersdorffite,Mo mostly in the form of jordisite,the primary existence form of V were clay adsorption and isomorphism,no independent V mineral,was found,some galena and sphalerite were also existed.Element Y was found in uraninite and coffinite,the high temperature mineral association of uraninite+gersdorffite+sphalerite was discovered in the air bubble holes of host rock,indicating the mineralization in Xiaoping depression was closely associated with deep source ore-bearing hydrothermal.Mineral occurrence can be divide into four types,air bubble holes,solution pores,sediment fissures,mineral gaps respectively,but the main were air bubble holes and solution pores.

关 键 词：铀多金属 黑色岩系 矿物赋存特征 海底喷流 湘西北 

分 类 号：P619.14[天文地球—矿床学]