红石泉铀矿床晶质铀矿矿物学特征研究及其找矿意义  

Mineralogical characteristics of uraninite in Hongshiquan uranium deposit and its prospecting significance

作　　者：杨建俊 王伟 王刚 王凯兴[1,2] 余驰达 刘晓东 YANG JianJun;WANG Wei;WANG Gang;WANG KaiXing;YU ChiDa;LIU XiaoDong(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,Jiangxi,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,Jiangxi,China;3203 Research Institute of China Nuclear Industry,Xianyang 410007,Shanxi,China)

机构地区：[1]核资源与环境国家重点实验室,东华理工大学,江西南昌330013 [2]东华理工大学地球科学学院,江西南昌330013 [3]中国核工业二〇三研究所,陕西咸阳410007

出　　处：《矿床地质》2023年第3期660-677,共18页Mineral Deposits

基　　金：国家自然科学基金项目(编号:42072095);东华理工大学博士科研启动基金项目(编号:DHBK2020014);中国核工业集团高校科研攻关项目(编号:201619)联合资助。

摘　　要：龙首山铀成矿带西段的红石泉铀矿床是中国典型的伟晶岩型铀矿床,具有“岩体型”矿化特征。文章以红石泉晶质铀矿为切入点,结合全岩地球化学与晶质铀矿矿物学以及元素地球化学特征,探讨红石泉矿床铀矿物蚀变演化及铀矿化特征,得出以下认识:①红石泉矿床原生晶质铀矿受明显热液蚀变改造,w(UO_(2)+ThO_(2)+PbO+REE_(2)O_(3)+Y_(2)O_(3))逐渐减少,w(CaO+SiO_(2)+FeO+Al_(2)O_(3))明显增加,在蚀变改造过程中U从晶质铀矿中释放,随流体迁移;②红石泉矿床晶质铀矿Pb丢失现象较普遍,其中在背散射图像中较亮的A类晶质铀矿Pb丢失机制为重结晶,其重结晶加权平均年龄为(416±18)Ma,而较暗的B类晶质铀矿Pb丢失机制为扩散(浸出);③红石泉矿床岩浆铀成矿阶段之后,存在后期热液铀成矿作用。根据全岩元素地球化学特征,结合区内正长岩结晶年龄,文章推测红石泉矿床热液铀成矿与正长岩浆分异的碱性热液关系密切。The Hongshiquan deposit,located in the western part of the Longshoushan uranium metallogenic belt,is a typical magmatic-type uranium deposit in China.Previous studies have mainly focused on the petrology and genesis of the deposit,but there has been a relative absence of research on the mineralogy of uraninite,which is the primary uranium mineral in the Hongshiquan deposit.This paper aims to discuss the alteration evolution of uraninite and the features of uranium mineralization in the Hongshiquan deposit,combining whole-rock geochemical characteristics with the characteristics of mineralogical and element geochemistry of uraninite.Several important findings have been obtained:①Primary uraninites in the Hongshiquan deposit have undergone significant hydrothermal alteration,resulting in a significant decrease in w(UO_(2)+ThO_(2)+PbO+REE_(2)O_(3)+Y_(2)O_(3))contents and an obvious increase in w(CaO+SiO_(2)+FeO+Al_(2)O_(3))contents.During the hydrothermal alteration process,uranium was released from uraninite and migrated with the hydrothermal fluid;②Pb loss in uraninite is common in the Hongshi quan deposit.The Pb loss mechanism of A-type uraninite,which shows brightness on BSE images,is recrystallization.The weighted mean age of A-type uraninite recrystallization is(416±18)Ma.B-type uraninite,which shows relatively higher darkness on BSE images,is due to diffusion or leaching;③Hydrothermal uranium mineralization occurred after the magmatic uranium mineralization stage in the Hongshiquan deposit.Based on the whole-rock geochemical characteristics of the Hongshiquan pegmatite granite and the crystallization age of the syenite distributed in the Hongshiquan area,it is inferred that hydrothermal uranium mineralization is closely related to the alkaline hydrothermal fluids differentiated from the syenite magma.

关 键 词：地质学 岩浆型铀矿床 晶质铀矿 成矿特征 红石泉铀矿床 

分 类 号：P619.14[天文地球—矿床学]