湘东北白沙窝伟晶岩型铍锂铌钽矿床中铍的赋存状态和成因机制  

Occurrence and ore-forming mechanism of beryllium in the Baishawo Be-Li-Nb-Ta pegmatite deposit in northeastern Hunan,South China

作　　者：范志伟 熊伊曲 陈星霖 文春华 邵拥军 FAN Zhiwei;XIONG Yiqu;CHEN Xinglin;WEN Chunhua;SHAO Yongjun(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitor,Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha,Hunan 410083,China;Hebei Key Laboratory of Green Development of Rock and Mineral Materials,Shijiazhuang,Hebei 050030,China;Hunan Provincial Key Laboratory of Geochemical Processes and Resoruce Environmental Effects,Geophysical and Geochemical Survey institute of Hunan,Changsha,Hunan 410014,China;Nonferrous Metals Mineral Resources Geological Survey Center,Changsha,Hunan 410083,China;Hunan Institute of Geological Survey,Changsha,Hunan 410116,China)

机构地区：[1]中南大学地球科学与信息物理学院有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083 [2]河北省岩石矿物材料开发重点实验室,河北石家庄050030 [3]地球化学过程与资源环境效应湖南省重点实验室,湖南长沙410014 [4]有色金属矿产地质调查中心,北京100029 [5]湖南省地质调查所,湖南长沙410116

出　　处：《地质学报》2025年第3期809-829,共21页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42172085);地球化学过程与资源环境效应湖南省重点实验室开放基金项目(编号GRE202308G);湖南省创新团队项目(编号2021RC4055);湖南省地质院科研项目(编号HNGSTP202105);湖南省研究生科研创新项目(编号CX20230199);河北省岩石矿物材料开发重点实验室开放基金课题(编号RM2024002)联合资助的成果。

摘　　要：铍(Be)作为关键金属,是航空、航天领域和新能源行业必不可少的工业原料。我国是主要的Be消费国,Be资源对外依存度高。湘东北白沙窝矿床是新发现的大型伟晶岩型Be-Li-Nb-Ta稀有金属矿床,但其Be的赋存状态和成因机制尚不明确。基于此,本次研究在系统的野外地质调查基础上,结合光学显微镜观察、扫描电镜、电子探针分析、LA-ICP-MS分析和矿物自动扫描等方法,对白沙窝3^(#)分带伟晶岩脉中的绿柱石、黑色电气石、石英、钠长石和云母进行了详细的岩相学及矿物学研究。结果表明:Be不仅以独立矿物形式赋存于绿柱石中,还以类质同象的形式赋存于黑色电气石、石英、钠长石及白云母中。绿柱石主要发育在3^(#)伟晶岩脉外侧带和过渡带中,外侧带绿柱石呈淡绿色,晶体颗粒大小为2~5 cm,与钠长石、白云母和石榴子石等矿物共生;过渡带中的绿柱石晶体颗粒较大(直径约50 cm),呈短柱状,晶体表面有平行于c轴的纵向纹理。3^(#)脉外侧带绿柱石中BeO、Li_(2)O和Cs_(2)O的含量分别为12.87%~14.01%、0.14%~0.33%和0.05%~0.12%;而过渡带绿柱石中的BeO的含量为13.38%~13.96%,Li_(2)O和Cs_(2)O含量分别为0.25%~0.39%和0.13%~0.39%,均稍高于外侧带绿柱石。此外,石英中Be含量(0.20×10^(-6)~7.13×10^(-6),平均值为2.50×10^(-6))均低于其他含Be矿物,黑色电气石(4.13×10^(-6)~8.73×10^(-6),平均值为5.94×10^(-6))与钠长石中的Be含量(1.22×10^(-6)~6.98×10^(-6),平均值为4.54×10^(-6))接近,而白云母中的Be含量(16.9×10^(-6)~53.8×10^(-6),平均值为21.77×10^(-6))相对较高。综合研究认为白沙窝3^(#)伟晶岩脉外侧带伟晶岩为花岗质熔体结晶分异成因,过渡带伟晶岩处于岩浆-热液过渡阶段,受到了后期热液流体的交代作用。白沙窝矿床中绿柱石与钠长石等碱性长石共生,且具有较好的工业价值,可采用酸法浮选等方法进行绿色选冶。本文为伟晶岩型�Beryllium(Be),as a critical element,is an essential industrial raw material inaerospace,aviation and the new energy industry.China is a major beryllium consumer with high external dependence.The Baishawo Be-Li-Nb-Ta deposit in northeastern Hunan Province is a newly discovered large pegmatite-type rare-metal deposit;however,the occurrence and ore-forming mechanism of beryllium within this deposit remain poorly understood.Here,we combined geology,SEM,EPMA,LA-ICP-MS and TIMA analysis,to investigate the petrographic and mineralogical features of beryl,tourmaline,quartz,albite,and muscovite of 3^(#)pegmatite in the Baishawo Be-Li-Nb-Ta deposit.The results show that Be is hosted in beryl as an independent mineral phase,but occurs in tourmaline,quartz,albite,and mica in an isomorphic form.Beryl mainly develops in the wall and intermediate zones of 3^(#)pegmatite.The wall zone beryl is light green in color with 2×3×5 cm in size and coexists with albite,muscovite,and garnet.The beryl crystal from the intermediate zone has large grain size(~50 cm),and presents a short columnar,with longitudinal lines parallel to the c-axis on the crystal surface.The beryl from the wall zone has BeO,Li_(2)O,and Cs_(2)O content of 12.87%~14.01%,0.14%~0.33%,and 0.05%~0.12%,respectively.The BeO content in beryl from the intermediate zone is 13.38%~13.96%,and the contents of Li_(2)O and Cs_(2)O are slightly higher than those in the wall zone,which are 0.25%~0.39%and 0.13%~0.39%,respectively.Quartz has the lowest Be content(0.20×10^(-6)~7.13×10^(-6),average 2.50×10^(-6)),but muscovite have highest Be content(16.9×10^(-6)~53.8×10^(-6),average 21.77×10^(-6))compared to tourmaline(4.13×10^(-6)~8.73×10^(-6),average 5.94×10^(-6))and albite(1.22×10^(-6)~6.98×10^(-6),average 4.54×10^(-6)).It is considered that the 3^(#)pegmatite is of granitic melt crystallization differentiation origin for wall zone pegmatite,but the pegmatite in the intermediate zone is in the magmatic-hydrothermal transition stage,which is subject to the metasomatism o

关 键 词：白沙窝稀有金属矿床 Be的赋存状态 绿柱石 伟晶岩 成因机制 

分 类 号：P61[天文地球—矿床学]