川西可尔因加达锂矿床矿物学研究及其指示意义

Mineralogical study and indicative significance of Jiada lithium deposit in Ke’eryin area, western Sichuan, China

中文关键词:含锂矿物  白云母  矿物学  电子探针分析  伟晶岩型锂矿  可尔因  加达锂矿

keywords:Lithium-bearing minerals  muscovite  mineralogy  electron probe microanalysis (EPMA)  pegmatite-type lithium deposit  Ke’eryin  Jiada lithium deposit

中文摘要:川西加达锂矿位于松潘-甘孜成矿带东缘的可尔因矿田内，是近年来发现的重要伟晶岩型锂矿床之一，矿床Li₂O资源量规模达超大型。为查明其稀有金属矿物的类型、赋存状态及成矿演化过程，文章以加达矿区典型伟晶岩型矿石为研究对象，系统开展了手标本观察、偏光显微镜鉴定、X射线衍射（XRD）、扫描电镜（SEM）及电子探针（EPMA）等工作。研究结果表明，矿石中主要含锂矿物包括锂辉石、锂绿泥石、磷锂铝石、磷锰锂矿和铁锂云母等，其他稀有金属矿物还包括铌锰矿和锡石，构成加达矿区主要的稀有金属矿物组合。矿物的组合特征与赋存状态显示，加达矿床经历了岩浆结晶、热液交代和表生风化3个阶段的演化过程。原生锂辉石在岩浆结晶早期富集形成，晚期P、F富集促使磷酸盐类矿物和富锂云母发育，后期热液活动则沿锂辉石晶界和裂隙交代形成蠕虫状锂辉石及锂绿泥石，进一步重新分配了锂元素。综上所述，加达矿区的锂矿化受岩浆高度结晶分异与热液交代的共同控制，反映出富Li-F-P体系演化下的伟晶岩型稀有金属成矿特征。文章从矿物学视角出发，厘清了加达矿区锂及伴生稀有金属的成矿演化过程，为区域上伟晶岩型锂等稀有金属矿床的找矿勘查提供了重要矿物学依据。

Abstract:The Jiada lithium deposit, located in the Koeryin ore field on the eastern margin of the Songpan-Ganzi metallogenic belt, is one of the most important pegmatite-type lithium deposits discovered in recent years, with a Li₂O resource of super-large scale. To clarify the types, occurrence state, and metallogenic evolution of rare-metal minerals, this study investigates representative pegmatite-type ores from the Jiada deposit area using hand specimen observation, petrographic analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). The results show that the major lithium-bearing minerals include spodumene, cookeite, amblygonite, lithiophilite, and zinnwaldite, while other rare-metal minerals mainly consist of manganocolumbite and cassiterite, forming the characteristic rare-metal mineral assemblage of the deposit. The mineral assemblages and their occurrences indicate that the Jiada deposit experienced three evolutionary stages: magmatic crystallization, hydrothermal metasomatism, and supergene weathering. Primary spodumene was enriched during the early stage of magmatic crystallization, whereas late-stage enrichment of P and F promoted the development of phosphate minerals and Li-rich micas. Subsequent hydrothermal activity altered spodumene along grain boundaries and fractures, producing vermicular spodumene and cookeite, which further redistributed lithium. In summary, the lithium mineralization of the Jiada deposit was jointly controlled by intense magmatic fractional crystallization and hydrothermal metasomatism, reflecting the metallogenic features of pegmatite-type rare-metal deposits in a Li-F-P enriched system. From a mineralogical perspective, this study elucidates the metallogenic evolution of lithium and associated rare metals in the Jiada deposit and provides important mineralogical insights for regional exploration of pegmatite-type lithium and related rare-metal deposits.