滇西新生代黄连沟铍矿床花岗伟晶岩演化及其对成矿的指示  

The evolution of granitic pegmatite from the Cenozoic Huangliangou beryllium deposit,West Yunnan and its implication for mineralization

作　　者：游亚元 何小虎 明添学 闫庆贺 陈会 YOU YaYuan;HE XiaoHu;MING TianXue;YAN QingHe;CHEN Hui(School of Earth Sciences,Yunnan University,Kunming 650500,China;Yunnan International Joint Laboratory of Critical Mineral Resource,Kunming 650500,China;Institute of Yunnan Geology Survey(Institute of Yunnan Geological Sciences),Kunming 650051,China)

机构地区：[1]云南大学地球科学学院,昆明650500 [2]云南省关键矿产资源国际联合实验室,昆明650500 [3]云南省地质调查院(云南省地质科学研究院),昆明650051

出　　处：《岩石学报》2024年第9期2878-2904,共27页Acta Petrologica Sinica

基　　金：云南省兴滇英才计划项目(C6213001155);云南省地质勘查基金管理中心新一轮找矿行动科研项目(Y202305);云南省教育厅科学研究基金项目(2024Y009)联合资助.

摘　　要：我国花岗伟晶岩型稀有金属矿床多形成于加里东期、印支期和燕山期,而新生代的花岗伟晶岩型稀有金属矿床报道较少。黄连沟铍(Be)矿床位于青藏高原东南缘滇西稀有金属成矿带,是滇西地区发育的典型新生代花岗伟晶岩型稀有金属矿床。加强该矿床的研究对深入认识我国新生代花岗伟晶岩型稀有金属矿床成因和丰富花岗伟晶岩型稀有金属成矿理论具有重要意义。铌钽铁矿和锡石U-Pb年代学研究表明,黄连沟稀有金属花岗伟晶岩主要形成于64.0±0.8Ma~66.0±0.3Ma,为新生代新特提斯洋俯冲闭合背景下的产物。电子探针和LA-ICP-MS元素原位微区分析表明,黄连沟钾长石伟晶岩、钠长石-钾长石伟晶岩和钠长石伟晶岩中白云母的Li、Cs、Rb、Be等微量元素含量、石榴子石中Mn的含量以及铌钽铁矿Ta含量、Ta/(Ta+Nb)值等表现出逐渐增加的趋势,表明它们的演化程度逐渐升高。钠长石-钾长石伟晶岩中大量热液电气石的出现,表明钠长石-钾长石伟晶岩在演化过程中存在高挥发分岩浆体系。石榴子石中FeO、MnO含量变化和白云中Cs含量及K/Rb比值变化趋势表明黄连沟稀有金属伟晶岩演化处于Be-Nb-Ta矿化阶段。黄连沟铍矿床区域演化及矿化特征表明,矿区西南方向花岗伟晶岩演化程度最高,该方向可能是矿区的重要找矿靶区。The granitic pegmatite-type rare-metal deposits in China are mostly formed in Caledonian,Indosinian and Yanshanian periods,while the Cenozoic granitic pegmatite-type rare-metal deposits are rarely reported.The Huangliangou beryllium(Be)deposit is located in the rare-metal metallogenic belt of West Yunnan on the southeastern margin of the Tibeten Plateau.It is a typical Cenozoic granitic pegmatite-type rare-metal deposit developed in the West Yunnan.Strengthening the study of this deposit is of great significance to deeply understand the genesis of Cenozoic granitic pegmatite-type rare-metal deposits and enrich the metallogenic theory of granitic pegmatite-type rare-metals in China.U-Pb geochronological studies of columbite-tantalite group minerals(CGM)and cassiterites show that the rare-metal granitic pegmatites in this deposit is mainly formed between 64.0±0.8Ma and 66.0±0.3Ma,which is the product of the closure of the Neo-Tethys Ocean subduction during Cenozoic.Electron microprobe analysis(EMPA)and LA-ICP-MS in-situ elemental microanalysis showed that the concentration of trace elements such as Li,Cs,Rb and Be of muscovite,Mn of garnet,Ta and Ta/(Ta+Nb)of columbite-tantalite group minerals from K-feldspar pegmatite,albite-K-feldspar pegmatite and albite pegmatite display an increasing trend,indicating that their evolution degree has gradually increased.The occurrence of a large amount of hydrothermal turmaline in albite-K-feldspar pegmatite indicates that there was a magmatic system with plenty of volatile for the albite-K-feldspar pegmatite.The variation of FeO and MnO contents in garnet and the trend between Cs content and K/Rb ratios in muscovite suggest that the Huangliangou rare-metal pegmatites have evolved into the Be-Nb-Ta mineralization stage.The regional evolutionary history and mineralization characteristics of the Huangliangou beryllium deposit show that the granitic pegmatites in the southwest direction have higher degree of evolution,which may be the most important prospecting target area in the

关 键 词：滇西 黄连沟 新生代 稀有金属 花岗伟晶岩 演化序列 

分 类 号：P588.131[天文地球—岩石学] P597.3[天文地球—地质学] P618.72