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利用EMPA研究新疆阿尔泰柯鲁木特112号伟晶岩脉中5个结构带内的石榴子石化学组成。结果表明,112号脉中石榴子石属于铁铝榴石-锰铝榴石系列,主要为锰铝榴石。相同结构内不同石榴子石具有相近的化学组成,不同结构带中的石榴子石的化学组成显著差异:相比早期结构带中的石榴子石,晚期结构中的石榴子石Fe含量增加,Mn含量降低。结合铌钽族矿物中相似的Mn-Fe演化趋势,我们提出岩浆-热液过程中富F流体相出溶可能是晚期结构带中石榴子石显示高Fe、低Mn组成的机理。112号脉中锰铝榴石比例较高,变化于64%~90%范围,集中在稀有金属花岗伟晶岩中的锰铝榴石组成范围,由此我们认为伟晶岩中高Mn O含量的锰铝榴石是伟晶岩内部Li矿化的矿物学标志。
Using EMPA, the chemical composition of garnet in five structural bands in the Peiljite 112, Altay, Xinjiang Autonomous Region was studied. The results show that the garnet in the No. 112 vein belongs to the almandine-malasite garnet series and is mainly composed of chalcopyrite. The different garnets in the same structure have similar chemical composition, and the chemical composition of garnet in different structural zones is significantly different: the content of Fe in garnet in the late structure increases compared to the garnet in the early structure, and the Mn Reduced content. In the light of similar Mn-Fe evolution in niobium-tantalum minerals, we propose that the dissolution of F-rich fluid in the magma-hydrothermal process may be the mechanism by which garnet in the late structural belt shows high Fe and low Mn. In the 112th vein, the proportion of cryptomelane is high, varying in the range of 64% -90%, concentrating on the composition of the almandine in the rare-metal granitic pegmatites. Therefore, we consider the high MnO content of pegmatites Almandine is the mineralogical indicator of Li mineralization in the pegmatite.