甘肃红石泉地区伟晶状白岗岩LA-ICP-MS锆石U-Pb年龄与铀成矿关系  

The LA-ICP-MS zircon U-Pb age of the pegmatoidal alaskite and its relationship with uranium mineralization in Hongshiquan area,Gansu Province

作　　者：戚佳伟 张树明[1,2] 杨春四 蓝德初 王利玲 QI Jiawei;ZHANG Shuming;YANG Chunsi;LAN Dechu;WANG Liling(State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, Jiangxi, China;Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China University of Technology, Nanchang 330013,Jiangxi,China;Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, Guangdong,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [2]东华理工大学放射性地质与勘探技术国防重点学科实验室,江西南昌330013 [3]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640

出　　处：《地质通报》2019年第4期562-572,共11页Geological Bulletin of China

基　　金：国家自然科学基金项目<龙首山产于花岗岩中的碱交代型铀矿床成矿机理研究>(批准号:41172079);<相山斑岩型铀矿床铀矿成矿深度和剥蚀程度多方法联合估算>(批准号:41862006)

摘　　要：白岗岩是大陆碰撞过程中陆壳低比例熔融的产物,与铀及多金属矿床在成因上密切关联。甘肃红石泉铀矿床含矿主岩为伟晶状白岗岩,前人对伟晶状白岗岩的成岩年龄研究较少且精度有限,影响了对铀矿床成因和构造背景的深入认识。对甘肃红石泉铀矿床含矿主岩——伟晶状白岗岩开展了高精度LA-ICP-MS锆石U-Pb同位素测年,获得伟晶状白岗岩成岩平均年龄值为2493.5Ma,形成时代为新太古代晚期—古元古代早期。认为伟晶状白岗岩应属于新太古代晚期-古元古代早期华北克拉通微陆块拼合作用后期的产物,同时也是华北克拉通约2.5Ga岩浆构造热事件在西部地块的响应。伟晶状白岗岩与红石泉铀矿床铀成矿没有直接成因关系,只是作为铀矿的含矿主岩。Alaskite is the product of low proportion melting during continental collision,which is closely related to the origin of uranium and polymetallic deposits. The pegmatoidal alaskite is the ore-bearing host rock in Hongshiquan uranium deposit. The previous research on the formation age of pegmatoidal alaskite is relatively weak and limited in accuracy, which affects the deep understanding of the genesis and tectonic background of uranium deposits. This paper focuses on high precision LA-ICP-MS zircon U-Pb isotopic dating for the ore-bearing host rock-pegmatoidal alaskite. The analytical result shows that the ages of the pegmatoidal alaskite are 2455~2500 Ma, suggesting late Neoarchean-early Paleoproterozoic. It is concluded that the pegmatoidal alaskite should be the product of the late assemblage of the North China Craton microcontinent block during the late Neoarchean to early Paleoproterozoic. It is also a response to the Ca.2.5 Ga magma tectonic thermal event in the western block of the North China Craton. As a result, there is no positive genetic relationship between the pegmatoidal alaskite and uranium mineralization,with only pegmatoidal alaskite being the ore-bearing host rock in Hongshiquan uranium deposit.

关 键 词：甘肃红石泉 白岗岩 LA-ICP-MS锆石U-PB年龄 铀矿床 

分 类 号：P588[天文地球—岩石学] P597.3[天文地球—地质学]