白云鄂博矿床钍富集过程及空间分布规律  

Thorium enrichment process and spatial distribution in the Bayan Obo deposit

作　　者：陈彪 孙庆 宋文磊 金海龙 李强[1] 候少春 王其伟[1] 杨占峰[1] 贾晓琪 魏威 刘雁江 CHEN Biao;SUN Qing;SONG Wenlei;JIN Hailong;LI Qiang;HOU Shaochun;WANG Qiwei;YANG Zhanfeng;JIA Xiaoqi;WEI Wei;LIU Yanjiang(Baotou Research Institute of Rare Earths,National Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou,Inner Mongolia 014030,China;State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an,Shaanxi 710069,China)

机构地区：[1]包头稀土研究院,白云鄂博稀土资源研究与综合利用全国重点实验室,内蒙古包头014030 [2]西北大学地质学系大陆动力学国家重点实验室,陕西西安710069

出　　处：《地质学报》2023年第11期3535-3549,共15页Acta Geologica Sinica

基　　金：国家重点研发计划项目(编号2020YFC1909100、2021YFC2901704、2022YFC2905300);内蒙古自治区自然科学基金面上项目(编号2021MS04004);白云鄂博稀土资源与综合利用国家重点实验室专项(编号2021Z2349、2022Z2406)联合资助的成果。

摘　　要：白云鄂博矿床为一特大型Fe-REE多金属矿床,同时伴生有巨量的钍资源。然而,目前开发利用的矿种主要是铁和稀土资源,钍资源利用率几乎为零。查明矿床中钍资源的赋存状态和分布规律及揭示钍资源的富集过程及机制是今后钍资源开发利用的重要基础。本文依托近些年的系统采样及分析测试成果,对白云鄂博主、东、西矿区570个样品进行了详细的矿物学观察和全岩化学分析,在不同类型矿石中识别出以硅钍石为主的独立含钍矿物,硅钍石除少量呈现被稀土矿物包裹现象外,通常以细脉状穿插于稀土矿物内部,显示其明显滞后富集的特点。矿区ThO_(2)平均品位达0.0322%,高出地壳钍克拉克值(9.6×10^(-6))30多倍,各种矿石类型中ThO_(2)含量具有明显的差别,在云母型、闪石型、霓石型和萤石型矿石中具有高含量Th O_(2),而白云石型矿石中ThO_(2)含量较低,指示矿区钍矿化主要形成于碱性热液交代和萤石化阶段。此外矿区随深度增加钍矿化作用加强,显示出矿床具有良好的钍资源成矿潜力。Bayan Obo deposit is a large Fe-REE polymetallic deposit with large thorium resources.However,iron and rare earth resources are the main minerals developed and utilized at present,while thorium resources are almost used up.For the development and utilization of thorium resources in the future,it is important to find the occurrence state and distribution law of thorium resources in ore deposits and reveal the enrichment process and mechanism of thorium resources.In this paper,based on the results of systematic sampling,analysis and testing in recent years,detailed mineralogical observation and wholerock chemical analysis were carried out on 570 samples from Baiyunebozhu,East and west mining areas.Independent thorium minerals,mainly silicorite,were identified in different types of ores.Silicorite,except a small amount of which were coated by rare earth minerals,is usually interspersed in rare earth minerals in the form of veins.It shows the characteristics of lag enrichment.The average grade of ThO_(2) in the mining area is 0.0322%,which is more than 30 times higher than the Clark value of the crust(9.6×10^(-6)).There are obvious differences in ThO_(2) content among various ore types,and high ThO_(2) content is distributed in mica,amphibole,girine and fluorite ores.The low content of ThO_(2) in dolomite ore indicates that thorium mineralization is mainly formed in alkaline hydrothermal metasomatism and fluorination.In addition,thorium mineralization is enhanced with the increase of depth,which indicates that the deposit has good thorium ore-forming potential.

关 键 词：钍资源 富集过程 分布规律 成矿潜力 白云鄂博矿 

分 类 号：P618.2[天文地球—矿床学]