地学前缘 ›› 2023, Vol. 30 ›› Issue (5): 275-297.DOI: 10.13745/j.esf.sf.2023.5.9

• 典型矿床实例研究 • 上一篇    下一篇

喜马拉雅成矿带嘎波伟晶岩型锂矿成矿时代、岩浆演化及成矿指示意义

郭伟康1(), 李光明1,*(), 付建刚1, 张海1, 张林奎1, 吴建阳1, 董随亮1, 杨玉林2   

  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), 四川 成都 610218
    2.成都理工大学, 四川 成都 610059
  • 收稿日期:2022-11-29 修回日期:2022-12-28 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:郭伟康(1990—),男,博士,工程师,主要从事矿产普查和勘探工作。E-mail: gwk_987@126.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项目(2019QZKK0806);国家重点研发计划项目(2021YFC2301903);国家自然科学基金项目(91955208);中国地质调查局地调项目(DD20230281);中国地质调查局地调项目(DD20230031)

Metallogenic epoch, magmatic evolution and metallogenic significance of the Gabo lithium pegmatite deposit, Himalayan metallogenic belt, Tibet

GUO Weikang1(), LI Guangming1,*(), FU Jiangang1, ZHANG Hai1, ZHANG Linkui1, WU Jianyang1, DONG Suiliang1, YANG Yulin2   

  1. 1. Chengdu Center, China Geological Survey (Geosciences Innovation Center of Southwest China), Chengdu 610218, China
    2. Chengdu University of Technology, Chengdu 610059, China
  • Received:2022-11-29 Revised:2022-12-28 Online:2023-09-25 Published:2023-10-20
  • Contact: LI Guangming

摘要:

近年来,喜马拉雅淡色花岗岩带稀有金属成矿作用得到了广泛的关注。错那洞、琼嘉岗等稀有金属矿的发现,揭开了喜马拉雅地区稀有金属矿产勘查和研究的序幕。已有工作显示该带有望成为一条新的世界级的Li-Be-W-Sn稀有金属成矿带。嘎波锂矿是在喜马拉雅成矿带东段发现的具有工业价值的伟晶岩型锂矿。本研究聚焦库拉岗日穹窿北东侧的嘎波锂矿,重点研究其成矿特征、形成时代、岩浆演化特征。嘎波矿区主要发育锂辉石、锂电气石、锂云母、透锂长石、铌钽铁矿、绿柱石等锂-铍-铷-铌钽稀有金属矿物。伟晶岩内部结构分带简单,锂辉石主要产在细粒钠长石锂辉石带和块体微斜长石锂辉石带中,前者为矿体的主要组成部分。独居石U-Pb定年结果显示嘎波锂辉石伟晶岩形成于中新世早期(23~21 Ma);其成矿年龄与藏南拆离系(STDS)活动的峰期一致,两者具有密切的时空成因联系。岩石学、矿物学、地球化学研究表明嘎波锂辉石伟晶岩具有高度分异演化的特征,熔体经历了斜长石、锆石、云母等矿物的分离结晶作用。云母化学成分显示:云母类型以白云母为主;随着岩浆分异程度的增高,云母中 Fe和Mg含量降低,Li含量升高,并出现代表极高分异演化程度的锂云母。嘎波锂矿是喜马拉雅淡色花岗岩稀有金属成矿理论一项重要的找矿成果,为丰富淡色花岗岩稀有金属成矿理论提供了极为重要的地质依据。

关键词: 伟晶岩型锂矿, 库拉岗日穹窿, 喜马拉雅成矿带, 淡色花岗岩, 嘎波

Abstract:

In recent years rare-metal metallogeny of the Himalayan leucogranite belt has attracted much attention, and the discovery of the Cuonadong and Qiongjiagang rare-metal deposits sets a prelude to the rare-metal exploration and research in the Himalayas. According to previous researches the Himalayan metallogenic belt is expected to become a new world-class Li-Be-W-Sn metallogenic belt. One example is the Gabo lithium pegmatite deposit in northeastern Kulagangri Dome. This study focuses on the metallogenic characteristics, formation age and magmatic evolution of the Gabo pegmatite deposit. Rare-metal (Li, Be, Rb, Nb, Ta) minerals of the Gabo pregmatites include spodumene, elbaite, lepidolite, petalite, columbite-tantalite and beryl. The pegmatites have simple zonal structures. Spodumene mainly occurs as fine albite-spodumene or massive microline-spodumene zones, where the former is the main component of ore body. Monazite U-Pb dating results show that the Gabo pegmatites were formed in the Early Miocene (23-21 Ma) coinciding with the period of peak activity of the southern Tibet detachment system (STDS), which indicate a close genetic relationship between pegmatite formation and STDS activities. According to their petrology, mineralogy and geochemistry, the Gabo pegmatites are highly differentiated and evolved, where plagioclase, zircon, mica and other minerals were formed during fractional crystallization of pegmatite-forming melts. According to chemical compositional analysis muscovite is the main mica type in the Gabo pegmatites, whilst the occurrence of lepidolite is indicative of high-level pegmatite differentiation as the increase of magmatic differentiation led to decrease of Fe-Mn contents and increase of Li content in mica. The Gabo lithium pegmatite deposit is an important achievement in rare-metal prospecting based on metallogenic models of the Himalayan leucogranite, which in turn greatly improves the metallogenic models.

Key words: lithium pegmatite deposit, Kulagangri Dome, Himalayan metallogenic belt, leucogranites, Gabo

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