摘要
龙首山铀成矿带中段的芨岭铀矿床是我国少有的钠交代型铀矿床,也是我国西北地区碱交代型铀矿床的典型代表。矿床中的铀矿物学及铀矿物元素地球化学特征研究对揭示矿床成因及流体作用过程具有重要意义。文章开展的最新铀矿物学研究表明:芨岭铀矿床铀矿物主要为晶质铀矿和沥青铀矿,原生晶质铀矿具较高的ThO_(2)、Y2O_(3)以及REE_(2)O_(3)含量,显示较低的SiO_(2)+CaO含量,指示其可能形成于高温岩浆期后热液,且未受到明显的后期热液改造。矿床中几乎所有的新鲜沥青铀矿均受到后期流体改造,根据蚀变沥青铀矿在背散射图片中呈现亮暗不同的灰度和不同化学成分特征,可将其分为蚀变沥青铀矿A和蚀变沥青铀矿B。与原生晶质铀矿相比,蚀变沥青铀矿A和B均显示较低的ThO_(2)+UO_(2)+REE_(2)O_(3)+Y2O_(3)+PbO以及较高的SiO_(2)+CaO含量,同时它们之间的化学成分特征指示新鲜沥青铀矿至少经历两期次成分不同的热液改造,其中一期次相对富Ca,另一期次相对富Si。
Located in the middle part of the Longshoushan uranium metallogenic belt,Jilin uanium deposit is a rare sodium metasomatic one and the represent of alkaline metasomatic uranium deposit in Northwest China.The study of uranium mineralogy and elements geochemistry is significant to reveal the genesis and fluid interaction process in the deposit.Study showed that the main uranium minerals of Jiling deposit were uraninite and pitchblende.The original uraninite is high in ThO_(2),Y2O_(3) and REE_(2)O_(3) and low in SiO_(2)+CaO,indicating they maybe formed under high-temperature of the magmatic-hydrothermal fluid,and were not significantly altered by the later hydrothermal fluid.Almost all the fresh pitchblende in Jiling uranium deposit have been altered during the later hydrothermal fluid activities.According to the different gray levels of backscattered image and chemical composition of the altered pitchblende,they can be divided into altered pitchblende A and altered pitchblende B.Compared with the original uraninite,the altered pitchblende A and B have lower content of ThO_(2)+UO_(2)+REE_(2)O_(3)+Y2O_(3)+PbO and higher content of SiO_(2)+CaO.The element compositions characteristics between these two altered pitchblende indicate that the fresh pitchblende has undergone at least two phases of hydrothermal alteration,one is relatively rich in Calcium and the other relatively rich in Silicon.
作者
王刚
余驰达
何佳军
邵东
刘涛
陈云杰
王伟
胡菲菲
王凯兴
WANG Gang;YU Chida;HE Jiajun;SHAO Dong;LIU Tao;CHEN Yunjie;WANG Wei;HU Feifei;WANG Kaixing(Research Institute No.203,CNNC,Xianyang,Shaanxi 712000,China;School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013,China;State Key Laboratory of Nuclear Resources and Environment,Nanchang,Jiangxi 330013,China)
出处
《铀矿地质》
CAS
CSCD
2021年第6期991-1000,共10页
Uranium Geology
基金
中国核工业地质局铀矿项目(编号:202002)
国家自然科学基金项目(编号:42072095)联合资助。
关键词
钠交代型铀矿床
晶质铀矿
沥青铀矿
成矿特征
龙首山铀成矿带
Na-metasomatic type uranium deposit
uraninite
pitchblende
metallogenic characteristic
Longshoushan uranium metallogenic belt
