投稿时间：2025-04-03
修订日期：2025-07-11
网络发布日期：2025-08-26
中文摘要:传统认识中，高品位锂矿（平均w(Li2O)>1%）主要为锂辉石伟晶岩。在新一轮找矿突破战略行动中，笔者在湖南大义山岩体南部发现一种特高品位蚀变花岗岩型锂矿体。根据钻孔揭露，w(Li2O)单工程最高可达1.93%，平均为1.28%，约为岩体平均背景值的65倍（岩体Li背景值约为99×10-6，换算w(Li2O)约为0.02%），具有较高的经济意义。与传统蚀变花岗岩型和伟晶岩型锂矿床不同，初步岩相学观察和19件岩芯样品矿物相分析表明，矿石中云母类矿物具含量高（最高可达40%）、片径小（约0.2~1.6 mm）的特征。锂主要赋存于铁锂云母和锂多硅白云母中，云母边缘发育热液交代迹象。该发现对大义山复式花岗岩体锂的超常富集规律有重要指示意义，今后有必要进一步对该类型锂矿开展综合地质调查和研究工作，也可为大义山岩体及周边地区类似找矿工作提供参考。
Abstract:Traditional conceptual frameworks posit that high-grade lithium (Li) deposits (w(Li2O)>1% on average) are primarily associated with spodumene pegmatites. During China’s recent National Mineral Resource Prospecting Breakthrough Program, the authors discovered a novel ultra-high-grade metasomatized granite-type Li orebody in the southern margin of the Dayishan composite granitic pluton in Hunan Province, China. Drill-core sampling revealed individual samples with Li2O concentrations as high as 1.93%, averaging 1.28%—an exceptional enrichment of nearly 65 times over the pluton’s background Li content (host rock Li averages ~99 ×10-6, equivalent to ~0.02% w(Li2O)). Unlike conventional metasomatized granite- or pegmatite-hosted lithium deposits, preliminary petrographic analysis and mineralogical characteristics of 19 drill-core samples indicate dominance of micas comprising up to 40% of the mineral assemblage, with flakes averaging 0.2~1.6 mm in size. Li hosted within zinnwaldite and Li-phengite, with hydrothermal metasomatic overgrowth textures observed along muscovite margins. This finding is critical for redefining Li enrichment mechanism within the Dayishan pluton, as it establishes a distinct magmatic-hydrothermal pathway for extreme Li concentration outside classic pegmatitic frameworks. Future investigations into this deposit type will require integrated geochronologic-thermodynamic modeling and three-dimensional structural analyses to elucidate the interplay of melt-fluid systems in such environments. Such efforts will not only refine exploration strategies for similarly anomalous lithophosphoric systems, but also provide geodynamic templates for evaluating undersampled crustal regions adjacent to the Dayishan pluton.
keywords:ultra-high-grade lithium deposit breakthrough in prospecting altered granite-type lithium deposit highly-fractionated granite Dayishan
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基金项目:本文得到国家自然科学基金（编号：42172085）、国家重点研发计划：与高分异花岗岩有关的铌钽铷铯成矿规律与资源潜力（编号：2024YFC2909300）和湖南省地质院骨干人才项目（编号：HNGSTP202541）联合资助
引用文本：
黄文海,杨齐智,熊伊曲,刘伟,禹俊,朱真真,王元,严彦,王兆钧.2025.湖南大义山岩体南部特高品位锂矿找矿突破及启示[J].矿床地质,44(4):918~924HUANG WenHai,YANG QiZhi,XIONG YiQu,LIU Wei,YU Jun,ZHU ZhenZhen,WANG Yuan,YAN Yan,WANG ZhaoJun.2025.Breakthrough and implications in prospecting ultra-high-grade lithium deposit in southern Dayishan intrusion, Hunan Province[J].Mineral Deposits44(4):918~924
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