赣南珠坑钨矿白云母矿物特征及其地质意义

Characteristics and Geological Significance of Muscovite in Zhukeng Tungsten Deposit,Southern Jiangxi Province

云母类矿物在矿床学研究中蕴含着重要成因信息,揭示锂等稀有元素赋存形式,为找矿认识提供重要线索。选取赣南珠坑钨矿中云母类矿物作为研究对象,通过岩相学和电子探针等研究手段开展了详细的矿物学研究。分析结果表明,矿床中云母属于铁锂云母,具有富Al、K,贫Mg、Ca、Li等特点,可分为原生白云母、交代平衡白云母和热液白云母。珠坑细粒白云母花岗岩中交代平衡白云母具有相对较高F,指示富F热液流体对围岩进行改造可能有利于W等成矿元素的富集;云母中K_(2)O、Al^(Ⅵ)含量与F含量以及Al_(2)O_(3)与FeO^(T)含量均呈一定的负相关性,表明珠坑花岗岩经历了钠长石化、白云母化等热液蚀变的叠加。通过与大湖塘、宜春414矿床对比发现,珠坑→大湖塘→宜春矿床中的热液白云母F含量呈逐渐呈降低趋势,暗示大湖塘和宜春414锂成矿潜力更好,表明热液白云母中F含量可以作为钨矿中找锂矿的矿化指标。

Micas contain important genesis information in the study of mineral deposits,reveal the forms of rare elements such as lithium,and provide an important breakthrough for the understanding of prospecting.The micas in the tungsten ore of Gannan Zhukeng were selected as the research object and detailed mineralogical research was carried out by petrography and electron probe,which can be divided into native muscovite,sympathetic equilibrium muscovite and hydrothermal muscovite.The major element results show that the mica in the deposit belongs to iron-lithium mica,which is rich in Al,K,poor in Mg,Ca,Li and so on.The alternating equilibrium muscovite in fine-grained muscovite granite in the pearl pit has a relatively high content of F,indicating that the modification of the surrounding rock by F-rich hydrothermal fluids may be conducive to the enrichment of mineralizing elements such as W.The contents of K_(2)O,Al~Ⅵ and F in mica,and the contents of Al_(2)O_(3) and FeO~T showed certain negative correlations,indicating that Zhukeng granite underwent superposition of hydrothermal alteration such as albite and muscovite.Compare with the Dahutang and Yichun 414 deposits,the F contents of hydrothermal muscovite in the Yichun 414→Dahutang tungsten deposit→Zhukeng tungsten deposit gradually decrease which suggests the potential of lithium mineralization in Dahutang and Yichun 414 were better.The F content in hydrothermal muscovite could be used as a mineralization index for lithium prospecting in tungsten ore.