地学前缘 ›› 2023, Vol. 30 ›› Issue (5): 134-150.DOI: 10.13745/j.esf.sf.2023.5.16

• 矿化富集机理 • 上一篇    下一篇

喜马拉雅成矿带嘎波锂矿铌铁矿族矿物学特征及对岩浆-热液过程的指示

付建刚1(), 李光明1,*(), 郭伟康1, 张海1, 张林奎1, 董随亮1, 周利敏2, 李应栩1, 焦彦杰1, 石洪召1   

  1. 1.中国地质调查局 成都地质调查中心(西南地质科技创新中心), 矿产地质室, 四川 成都 611230
    2.国家地质实验测试中心, 北京 100037
  • 收稿日期:2022-12-10 修回日期:2023-03-01 出版日期:2023-09-25 发布日期:2023-10-20
  • 通讯作者: 李光明
  • 作者简介:付建刚(1987—),男,博士,副研究员,主要从事构造地质与成矿理论研究工作。E-mail: fujiangangcd@163.com
  • 基金资助:
    国家科学技术部第二次青藏高原综合科学考察研究资助项目(2019QZKK0806);国家自然科学基金项目(91955208);国家重点研发计划项目“我国西部伟晶岩型锂等稀有金属成矿规律与勘查技术”课题“北喜马拉雅锂等稀有金属找矿预测与勘查示范(2021YFC2901903);中国地质调查局项目“冈底斯—藏南铜钼锑铬多金属矿战略性矿产调查评价”(DD20230337);喜马拉雅中段锂等稀有金属矿产地质调查(DD20230281)

Mineralogical characteristics of columbite group minerals and its implications for magmatic-hydrothermal transition in the Gabo lithium deposit, Himalayan metallogenic belt

FU Jiangang1(), LI Guangming1,*(), GUO Weikang1, ZHANG Hai1, ZHANG Linkui1, DONG Suiliang1, ZHOU Limin2, LI Yingxu1, JIAO Yanjie1, SHI Hongzhao1   

  1. 1. Department of Mineral Geology, Chengdu Center, China Geological Survey (Geosciences Innovation Center of Southwest China), Chengdu 611230, China
    2. National Geological Experiment and Test Center, Beijing 100037, China
  • Received:2022-12-10 Revised:2023-03-01 Online:2023-09-25 Published:2023-10-20
  • Contact: LI Guangming

摘要:

嘎波伟晶岩型锂矿位于西藏喜马拉雅成矿带东段的库拉岗日穹窿东北端,是最近新发现的稀有金属矿床。含矿伟晶岩主要赋存在库拉岗日穹窿滑脱系的大理岩中,成矿元素以锂为主,共生铍铌钽等稀有金属。本文对锂辉石伟晶岩脉中铌铁矿族矿物开展了详细的矿物学、背散射电子成像和能谱元素面扫描分析。岩相学研究表明锂辉石伟晶岩中铌铁矿族矿物内部结构十分复杂,主要包括正向条带结构、反向条带结构、韵律环带结构和复杂结构4种类型。铌铁矿族矿物的内部结构和成分特征,有效记录了锂辉石伟晶岩形成演化的3个阶段:第一阶段,对应于正岩浆阶段的末期,形成铌铁矿族矿物核部,成分相对均一,没有环带的晶体,以富Nb和Fe为特征;第二阶段,对应岩浆-热液过渡阶段的早期,形成铌铁矿族矿物的正向条带结构、反向条带结构和韵律环带结构,以Nb、Ta、Fe、Mn元素含量周期性变化为特征;第三阶段,对应于岩浆-热液过渡阶段的晚期,该阶段形成铌铁矿族矿物的复杂结构,以大量富Ta和富Mn流体交代为特征。研究结果表明,铌铁矿族矿物内部结构对揭示锂辉石伟晶岩的形成过程与岩浆-热液演化过程具有很好的指示意义。

关键词: 锂矿, 铌铁矿族矿物, 花岗伟晶岩, 稀有金属, 岩浆-热液过渡, 库拉岗日穹窿, 喜马拉雅成矿带

Abstract:

The newly discovered Gabo lithium deposit in the northwestern Kulagangri Dome, eastern Himalayan metallogenic belt, contains spodumene pegmatite hosted in marbles of the dome's detachment system, where lithium, beryllium, niobium and tantalum are the dominant ore-forming elements. In this paper, columbite-group minerals (CGM) in spodumene pegmatite dikes are investigated through detailed mineralogical analysis, including electron scanning microscopy (ESM) with backscattered electron imaging (BSE) and energy dispersive spectroscopy (EDS) elemental analysis. The structure of CGM in spodumene pegmatite is highly complex, featuring normal zoning, reverse zoning and rhythmic-ring zoning structures and complex texture, which reveal a three-stage formation and evolutionary process of spodumene pegmatite in the Gabo lithium deposit. The first stage, corresponding to the late orthomagmatic stage, forms the Nb, Fe-enriched CGM crystal core from residual peraluminous granitic melt, without clear zoning structures. The second stage, corresponding to the early stage of magmatic-hydrothermal transition, develops the zoning structures characterized by periodic changes of Nb/Ta/Fe/Mn contents. And the third stage, corresponding to the late stage of magmatic-hydrothermal transition, forms the complex mineral texture via extensive metasomatism. These results show that the mineral structure of CGM can be used to reveal the formation and magmatic-hydrothermal evolution of spodumene pegmatite.

Key words: lithium deposit, columbite group minerals, granite pegmatite, rare metal, magmatic-hydrothermal transition, Kulagangri Dome, Himalayan metallogenic belt

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