康滇地轴前震旦纪混合岩铀成矿作用研究进展及找矿方向  

RESEARCH PROGRESS AND PROSPECTING DIRECTION OF URANIUM MINERALIZATION IN PRE-SINIAN MIGMATITE IN KANGDIAN AXIS AREA

作　　者：张成江[1,2,3] 姚建 徐争启 陈友良[1,2] 宋昊 ZHANG Chengjiang;YAO Jian;XU Zhengqi;CHEN Youliang;SONG Hao(College of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Sichuan Key Laboratory of Earth Science and Technology,Chengdu,Sichuan 610059,China;Key Laboratory of Earth Eploration and Information Technology,Ministry of Education,Chengdu,Sichuan 610059,China;No.280 Institute of Nuclear Industry,Guanghan,Sichuan 618300,China)

机构地区：[1]成都理工大学地球与行星科学学院,四川成都610059 [2]地学核技术四川省重点实验室,四川成都610059 [3]地球勘探与信息技术教育部重点实验室,四川成都610059 [4]核工业二八0研究所,四川广汉618300

出　　处：《矿物岩石》2024年第3期64-77,共14页Mineralogy and Petrology

基　　金：国家自然科学基金项目(批准号:41872079);成都理工大学珠峰科学研究计划项目(编号:2023ZF11413);中国核工业地质局项目(编号:AH2023-0410)。

摘　　要：近年来在康滇地轴中南段前震旦纪混合岩区发现了以国际上罕见、具有极高科学研究价值的粗粒晶质铀矿和特富铀矿石为的特征的铀矿类型。本次研究在研究团队研究基础上,综合前人研究成果,较系统分析了特富铀矿特征及成矿作用,指出了存在的主要科学问题,探讨了今后的研究思路与找矿方向。研究认为,康滇地轴产于混合岩中的铀矿存在两类明显不同的成矿类型,代表了两期成矿作用的产物:早期为典型的岩浆成矿作用,成矿元素组合为铀-钛-磷,晶质铀矿与钛铁矿、磷钇矿、独居石、金红石、锆石、钍石、方钍石、氟磷灰石、榍石紧密共生,基本不含硫化物;晚期为与岩浆期后高温热液有关的热液成矿作用,典型成矿元素组合为铀-钼-铜-硫,晶质铀矿与黄铁矿、磁黄铁矿、辉钼矿紧密共生。铀成矿时代主要集中于760~1 000 Ma,形成于新元古代由挤压造山向拉张伸展转化的地球动力学背景。成矿与混合岩化过程中深熔作用产生的钠质岩浆或与其有关的气液流体关系密切,碱质岩浆演化晚期富Si, P,F等流体分异是粗粒晶质铀矿形成的关键作用,深熔作用与大型韧性剪切带耦合对铀成矿具有重要的控制作用。早期与韧性剪切作用有关的以深熔岩浆贯入为主形成的混合岩造成了铀的初步富集,局部形成低品位铀矿化,后期构造-流体叠加形成了极高品位铀矿,成矿后构造活动和地壳隆升对矿体破坏改造明显。研究表明,康滇地轴存在形成高强度铀矿化的地质事件和成矿作用,具有寻找特富铀矿的潜力。In recent years,the discovery of coarse-grained and ultra-rich uranium ore types in the Pre-Sin-ian migmatite area of the central and southern Kangdian Axis has garnered significant attention due to their rarity and high scientific value.Building on previous research,our team systematically analyzed the char-acteristics and mineralization processes of these ultra-rich uranium ore deposits,identified key scientific problems,and discussed future research and prospecting directions.We identified two types of uranium deposits in the migmatite of the Kangdian Axis,resulting from two distinct stages of uranium mineraliza-tion.The initial stage involved typical magmatic mineralization,characterized by a uranium-titanium-phos-phorus element combination.In this stage,crystalline uraninite is closely associated with minerals such as ilmenite,phosphoyttrite,monazite,rutile,zircon,thorite,cubic thorite,fluorapatite,and sphene,with a notable absence of sulfides.The later stage is related to hydrothermal mineralization that occurred post-magmatic activity.This stage features a typical ore-forming element combination of uranium,molybde-num,copper,and sulfur,with crystalline uraninite closely associated with pyrite,pyrrhotite,and molyb-denite.The age of uranium metallogenesis in the region is primarily concentrated between 760 and 1000 million years ago,corresponding to the Neoproterozoic era,during the transition from compressional orog-eny to extensional tectonics.The differentiation of silicon,phosphorus,and fluorine-rich fluids during the late stages of alkaline magmatic evolution is crucial for the formation of coarse-grained crystalline uranium deposits.Additionally,the coupling effects of deep melting processes and extensive ductile shear zones play a significant role in controlling uranium mineralization.Our findings suggest that the initial stage of uranium enrichment and low-grade mineralization was facilitated by deep magma penetration related to ductile shearing,leading to the formation of migmatite.In the subsequent

关 键 词：特富铀矿 粗粒晶质铀矿 成矿作用 前震旦纪 康滇地轴 

分 类 号：P619.14[天文地球—矿床学]