赣南富城花岗岩中显微-超显微晶质铀矿的厘定及成因  

Detection of Micro and Super-Micro-Grained Uraninite in Fucheng Granite Pluton,Southern Jiangxi Province,China and Its Genetic Implication

作　　者：章邦桐[1] 吴俊奇[1] 凌洪飞[1] 陈培荣[1] 

机构地区：[1]内生金属矿床成矿机制研究国家重点实验室(南京大学),南京大学地球科学与工程学院,江苏南京210093

出　　处：《矿物学报》2011年第2期166-172,共7页Acta Mineralogica Sinica

基　　金：中国核工业地质局十一五基础科研项目(编号:YK08);内生金属矿床成矿机制研究国家重点实验室研究项目(编号:2008-Ⅰ-04);教育部科学研究重大项目(编号:306007)

摘　　要：通过显微镜下观察和电子探针成分分析,厘定了存在于赣南富城强过铝质产铀花岗岩黑云母、白云母、长石中的显微晶质铀矿。根据其成分及矿物组合特征并结合U-Pb同位素年龄测定判明其属原生成因。此外,采用核诱发裂变径迹法,根据白云母探测器上存在的星点状裂变径迹中心,判断造岩矿物(长石、石英)中可能存在超显微级的晶质铀矿核晶。花岗岩中原生晶质铀矿的存在一方面印证了U在Si-O聚合程度增高的花岗岩浆中易与O2-结合形成铀-氧配位多面体的化学键能理论,另一方面也成为花岗岩具有较高产铀能力的地球化学标志之一。Based on microscopic observation and electron microprobe analysis,the micro-grained uraninites in biotite,muscovite and plagioclase from the Fucheng strongly peraluminous granite pluton in southern Jingxi province,China were determinated.According to the mineral assemblage of the Fucheng pluton and the composition as well as U-Pb age of the uraninites,it is confirmed that these uraninites are attributed to primary genesis.Moreover,by using nuclei-induced fission-track method,some scatterred densely distributed fission-track spots in muscovite detector were found,which might indicate existence of uranium as independent mineral phase in rock-forming minerals.This mineral phase might be the nuclei of super-micro-grained uraninite.The chemical bond energy theory on forming U-O coordination polyhedra with increasing degree of Si-O polymerization in granite melt is proved by the existence of primary uraninite in granite.On the other hand,the primary uraninite can also be used as an important geochemical criterion for uranium metallogenetic capacity of uranium-bearing granite.

关 键 词：显微-超显微晶质铀矿 核诱发裂变径迹 化学键能 富城产铀花岗岩 赣南 

分 类 号：P571[天文地球—矿物学] P575.1[天文地球—地质学]