下庄新桥西铀矿床硫化物地球化学特征及其地质意义

Geochemical Characteristics of Sulfides in Xinqiaoxi Uranium Deposit of Xiazhuang and Its Geological Significances

新桥西铀矿床为下庄矿田内的铀矿床之一,位于贵东岩体东部。文章利用电子探针分析技术(EPMA)测定了新桥西铀矿床中黄铁矿、闪锌矿的微量元素组成。数据显示,该矿床中黄铁矿、闪锌矿具富Fe、Zn亏S的特征,其中黄铁矿主要富集Mo、Mn、Cu、Zn、As、Co、Ni、Pb、U;闪锌矿富集Mo、Mn、Fe、Cu、Cd。Cu、Fe、As、Co、Ni、Zn、Pb、Mo及Mn等微量元素可能以矿物包体或类质同象的形式存在于黄铁矿和闪锌矿中;黄铁矿中Co、Ni、Mo、As与U在流体中具相似的地球化学行为,可能具有相似的物质来源。硫化物微量元素特征指示其主要形成于中-浅部、中温成矿环境。结合下庄矿田的成矿地质背景,认为新桥西铀矿床属于典型的岩浆热液型矿床。

Xinqiaoxi uranium deposit,located in the east of Guidong pluton,is one of the uranium deposits in Xiazhuang mineralization cluster.The trace element composition of pyrite and sphalerite in Xinqiaoxi uranium deposit was determined by electron probe microanalysis(EPMA).The results show that pyrite and sphalerite in the deposit are rich in Fe and deficient in spyrite which is characterized by enrichment of Mo、Mn,Cu,Zn,As,Co,Ni,Pb,U;sphalerite is rich in Mo,Mn,Fe,Cu,Cd.Cu,Fe,As,Co,Ni,Zn,Pb,Mo,Mn and other trace elements may mainly occur in pyrite and sphalerite in the form of isomorphism or mineral inclusions;U in pyrite has similar geochemical behavior with Mo,As,Co and Ni in fluid,and may come from similar material sources.The characteristics of sulfide trace elements show that it was mainly formed in the medium shallow and medium low temperature metallogenic environment.Referring to the metallogenic geological background of Xiazhuang area,Xinqiaoxi uranium deposit belongs to a typical magmatic hydrothermal deposit.