贵州兴义地区大际山铀多金属矿床成因:矿石特征与铀赋存状态  

Genesis of the Dajishan uranium polymetallic deposit in the Xingyi area,Guizhou Province:Ore characteristics and occurrence of uranium

作　　者：潘澄雨[1] 吴玉[1] 刘畅 王凤岗[1] 田建吉[1] 徐伟 韩文文 肖昌浩 张文高[3] PAN Cheng-yu;WU Yu;LIU Chang;WANG Feng-gang;TIAN Jian-ji;XU Wei;HAN Wen-wen;XIAO Chang-hao;ZHANG Wen-gao(Beijing Research Institute of Uranium Geology,CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Techniques,Beijing 100029,China;No.280 Institute of Nuclear Industry,Guanghan 618300,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,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]核工业二八〇研究所,四川广汉618300 [3]中国地质科学院地质力学研究所,北京100081

出　　处：《矿物学报》2021年第1期23-32,共10页Acta Mineralogica Sinica

基　　金：中国核工业地质局铀矿地质调查项目(编号:201922);中国核工业地质局铀矿地质科研项目(编号:201922-2);中国地质调查局地质调查项目(编号:DD20190161)。

摘　　要：大际山铀多金属矿床是黔西南地区鲜有的碳硅泥岩型铀矿床,有关该矿床的矿化特征和成因研究涉及甚少。本文利用α径迹蚀刻、光学显微镜、激光拉曼光谱、扫描电镜和电子探针等多种方法,对大际山铀多金属矿床的矿石组构特征和铀的赋存状态进行了细致研究。结果表明,铀多金属矿石主要呈角砾状、浸染状和细脉状构造,矿石中以发育大量黄铁矿、白铁矿、硫钼矿和有机质为特征,还可见少量方铅矿和闪锌矿。铀主要以"不可见铀"和显微状沥青铀矿等形式存在,其中,沥青铀矿颗粒细小,多以星点状、粒状分布在金属硫化物颗粒内部或呈不规则团块状、絮状赋存在不同矿物颗粒的边缘或间隙部位,另有少量不规则细脉状、网脉状沥青铀矿充填于碳酸盐岩角砾的裂隙中。结合野外矿体严格受构造控制、围岩蚀变强烈和赋矿围岩中铀含量较低等基本地质特征,推测大际山铀多金属矿床应属于低温热液型铀矿床类型。The Dajishan uranium polymetallic deposit,which is located in the Southwestern Guizhou,China,has been regarded as a carbonaceous-siliceous-pelitic rock-type uranium deposit.However,the mineralization characteristics and genesis of this uranium polymetallic deposit are poorly studied.In the present paper,αtrack etching,microscope identification,laser Raman spectroscopy,scanning electron microscope,and electron probe microanalysis are used to carry out detailed studies of the ore fabrics,mineral compositions,and occurrence of uranium of the Dajishan uranium polymetallic deposit.The results show that uranium polymetallic ores,with brecciated,disseminated,and veinlet structures,contain a large amount of pyrite,marcasite,molybdenite,and organic matter,and a small amount of galena and sphalerite.Uranium occurred as invisible uranium and microscopic pitchblende,which is mostly in form of disseminated tiny particles within the metallic sulfide grains,or in form of irregular clumping and flocculent patches along the edges or gaps of different mineral grains,with minor pitchblende occurred as irregular veinlets or stockwork veins filling in cracks of carbonate fragments of breccias.With the combination of general geological characteristics that uranium orebodies strictly hosted in faults and interstratified fracture zones,the strong hydrothermal alteration of host rocks,and relatively low U contents of wall rocks,it is believed that the Dajishan uranium polymetallic deposit should be assigned to the low-temperature hydrothermal uranium deposit.

关 键 词：矿石特征 铀赋存状态 矿床成因 大际山铀多金属矿床 贵州兴义 

分 类 号：P611[天文地球—矿床学] P579[天文地球—地质学]