华南花岗岩型铀矿床主要特征与成矿作用研究进展  

General characteristics and research progresses in metallogenesis of granite-related uranium deposits in South China

作　　者：张龙 陈振宇[3] 汪方跃[1,2] ZHANG Long;CHEN ZhenYu;WANG FangYue(School of Resources and Environmental Engineering,Ore Deposit and Exploration Centre(ODEC),Hefei University of Technology,Hefei 230009,China;Anhui Province Engineering Research Center for Mineral Resources and Mine Environments,Hefei 230009,China;MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]合肥工业大学资源与环境工程学院,合肥工业大学矿床成因与勘查技术研究中心(ODEC),合肥230009 [2]安徽省矿产资源与矿山环境工程技术研究中心,合肥230009 [3]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《岩石学报》2021年第9期2657-2676,共20页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42002077、91962218、41741010);中央级公益性科研院所基本科研业务费(KK2011);中央高校基本科研业务费专项(PA2019GDZC0093)联合资助.

摘　　要：花岗岩型铀矿床是我国最重要的铀矿床类型之一,且主要分布在华南地区。本文在简要介绍华南花岗岩型铀矿床主要地质特征的基础上,重点总结了华南花岗岩型铀矿床的产铀花岗岩、成矿时代、成矿流体和成矿物质来源等方面的研究进展。华南花岗岩型铀矿床主要分布在华夏地块,以桃山-诸广铀成矿带最为重要。矿床以中小型(300~3000t U)和中低品位(0.05%~0.2%U)为主。产铀花岗岩主要形成于三叠纪(240~205Ma)和侏罗纪(165~150Ma)两个时期,属于S型花岗岩,源区以泥质沉积岩为主。三叠纪过铝质淡色花岗岩是有利的铀源岩,其中铀主要赋存于晶质铀矿。黑云母、晶质铀矿、磷灰石和锆石成分特征是评价花岗岩产铀潜力的有效工具。华南大多数花岗岩型铀矿床形成于白垩纪-古近纪(110~50Ma),以后生热液成因为主,其形成主要与区域白垩纪-古近纪岩石圈伸展作用和幔源基性岩浆活动有关。成矿流体以大气降水为主,成矿温度集中在120~260℃、盐度一般小于10%NaCleqv,铀在流体中主要以铀酰碳酸络合物和铀酰氟化物形式迁移,物理化学条件变化和CO 2去气导致铀在有利部位沉淀。文章指出应加强花岗岩中铀活化机制、铀成矿时代、以及下庄铀矿田侏罗纪(175~145Ma)铀成矿作用研究。Granite-related uranium deposits are one of the most important types of uranium deposits in China,and they mainly occur in South China.Based on the brief introduction of main geological characteristics of granite-related uranium deposits in South China,this study aims to make a review of the research progresses of U-bearing granites,mineralization ages,ore-forming fluids and materials of these deposits.The majority of these deposits occur in the Cathaysia Block,where the Taoshan-Zhuguang uranium belt is the most important.These uranium deposits are mostly small to medium sized(300~3000t U)and are low to medium grade(0.05%~0.2%U).Uranium-bearing granites were mainly emplaced during the Triassic(240~205Ma)and Jurassic(165~150Ma).These granites belong to S-type granites,mainly derived from the partial melting of pelitic sedimentary sources.Triassic peraluminous leucogranites are the favorable uranium source rocks in which the U is mainly hosted by uraninite.Chemical compositions of biotite,uraninite,apatite,and zircon are a useful tool for evaluating the uranium fertility of granites.Uranium mineralization mainly took place during the Cretaceous-Paleogene(110~50Ma).The majority of granite-related uranium deposits in South China are epigenetic in origin,and their formation is closely associated with regional Cretaceous-Paleogene lithospheric extension events and related mantle-derived mafic magmatism.Their ore-forming fluids are mainly composed of meteoric waters with temperatures of 120~260℃and low salinities(<10%NaCleqv),and uranium is chiefly transported as uranyl carbonate and fluoride complexes in fluids.Uranium is precipitated as a result of physicochemical changes and CO 2 degassing in favorable sites.This study suggests that it is necessary to strengthen the research on mobilization mechanism of uranium in granites,metallogenetic ages,and Jurassic(175~145Ma)uranium mineralization in the Xiazhuang uranium ore field.

关 键 词：花岗岩型铀矿床 华南 铀成矿作用 产铀花岗岩 成矿模型 

分 类 号：P611[天文地球—矿床学] P619.14[天文地球—地质学]