东昆仑造山带海德乌拉铀矿床成矿流体特征研究  

Study on fluid characteristics of the Haidewula uranium deposit,East Kunlun orogenic belt

作　　者：朱坤贺 王凯兴[1,2] 刘晓东 段建华[3] 李彦强 吴佳 余驰达[1] 雷勇亮[1,2] ZHU Kunhe;WANG Kaixing;LIU Xiaodong;DUAN Jianhua;LI Yanqiang;WU Jia;YU Chida;LEI Yongliang(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang,Jiangxi 330013,China;School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013,China;Qinghai Nuclear Industry Geological Bureau,Xining,Qinghai 810001,China)

机构地区：[1]核资源与环境国家重点实验室,东华理工大学,江西南昌330013 [2]东华理工大学地球科学学院,江西南昌330013 [3]青海省核工业地质局,青海西宁810001

出　　处：《地质学报》2024年第2期467-480,共14页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42072095);中国核工业集团高校科研攻关项目(编号201619);教育厅科技计划项目(编号GJJ200717);青海省科技厅重点研发与转化计划“青海省东昆仑火山岩型铀矿资源调查理论创新与找矿突破”(编号2021-SF-157);东华理工大学研究生创新基金项目(编号DHYC-202212)联合资助的成果。

摘　　要：东昆仑造山带海德乌拉铀矿床是近些年西北地区最新探明的与火山岩有关的独立铀矿床,该矿床的发现为东昆仑造山带探寻热液型铀矿床提供了指示意义。本文选择与海德乌拉铀矿成矿期相关的透明矿物(粉红色方解石、紫黑色萤石及石英)作为研究对象,系统地开展C-H-O同位素和流体包裹体研究,查明该矿床成矿流体的来源与性质,并探讨矿床成因。研究结果表明,海德乌拉铀矿床成矿期石英中主要为H2O气液两相包裹体,少见CO_(2)-H2O两相包裹体;在粉红色方解石脉、紫黑色萤石脉中流体包裹体均含H_(2)O气液两相包裹体,在粉红色方解石脉中偶见纯液相包裹体,均未见到纯气相及含固相包裹体。成矿期粉红色方解石、紫黑色萤石及石英中包裹体均一温度范围分别为133~187℃(均值163℃)、127~204℃(均值169℃)、183~287℃(均值219℃),盐度范围分别为1.40%~7.02%NaCleq(均值3.65%NaCleq)、0.53%~3.06%NaCleq(均值1.26%NaCleq)、7.17%~17.26%NaCleq(均值为11.46%NaCleq)。流体包裹体气相成分以H_(2)O为主,另含少量CO_(2)等。C-H-O同位素实验数据表明,流体中δ^(13)CFluid-V-PDB、δDFluid-V-SMOW、δ^(18)OFluid-V-SMOW值的变化范围分别为1.59‰~1.00‰、71‰~63‰、0.03‰~3.72‰,表明成矿流体并非单一来源,可能为大气降水与岩浆水混合来源。此外,沥青铀矿的沉淀主要是由于流体与围岩的相互反应所引起的物理化学条件变化加上流体沸腾/CO_(2)去气,最终导致了沥青铀矿等成矿物质发生大规模的卸载与沉淀。The Haidewula uranium deposit in the East Kunlun orogenic belt is a newly discovered independent uranium deposit related to volcanic rocks in Northwest China.The discovery of the deposit provides an indication for the exploration of hydrothermal uranium deposits in the East Kunlun orogenic belt.in this paper,the transparent minerals(pink calcite,purple black fluorite and quartz)related to the ore-forming period of the deposit are selected as the research objects.A systematic study of the C-H-O isotopes and fluid inclusions are carried out to find out the source and nature of the ore-forming fluid,and to explore the genesis of the deposit.The results show that the quartz of the ore forming period of the Haidewula uranium deposit is mainly composed of H_(2)O gas-liquid two-phase inclusions,with few CO_(2)-H_(2)O twophase inclusions;fluid inclusions in calcite vein and fluorite vein contain H_(2)O gas-liquid two-phase inclusions.Pure liquid phase inclusions are occasionally seen,but pure gas phase and solid phase inclusions are not seen in calcite veins.The homogenization temperature range of inclusions in calcite,fluorite and quartz during mineralization is from 133℃to 187℃(mean 163℃),from 127℃to 204℃(mean 169℃),and from 183℃to 287℃(mean 219℃)respectively,and the salinity range is from 1.40%NaCleq to 7.02%NaCleq(mean 3.65%NaCleq),from 0.53%NaCleq to 3.06%NaCleq(mean 1.26%NaCleq),from 7.17%NaCleq to 17.26%NaCleq(mean 11.46%NaCleq).The gas phase composition of fluid inclusions is mainly H_(2)O,and a small amount of CO_(2).The experimental data of C-H-O isotope show that the variation ranges of δ^(13)CFluid-V-PDB,δDFluid-V-SMOW,δ^(18)OFluid-v-smow values are from 1.59‰to 1.00‰,from 71‰to 63‰,from 0.03‰to 3.72‰respectively,indicating that the ore-forming fluid is not a single source,and may be a mixed source of atmospheric precipitation and magmatic water.In addition,the precipitation of pitchblende is mainly due to the changes in physical and chemical conditions caused by the interacti

关 键 词：火山岩型铀矿床 成矿流体 流体包裹体 激光拉曼光谱 C-H-O同位素 

分 类 号：P619.14[天文地球—矿床学]