【摘要】 仁里5号伟晶岩脉是湖南仁里超大型铌钽多金属矿床中含矿性最好且分带完整的一条含铌钽矿脉,云母作为其中的贯通性矿物出现于各分带中,由外部带至内部带表现出不同的成分和结构特征。文章通过对5号脉各带中的云母矿物进行详细的电子探针（EPMA）分析,查明了不同分带中云母矿物的演化规律:自外向内云母类型从白云母→锂云母的方向变化,Ⅰ带→Ⅲ带主要为白云母,Ⅳ带起出现富锂云母类型,并开始发育多种不平衡和交代结构;Ⅰ带→Ⅳ带云母的Li、Rb、Cs、F、Mg、Ti含量逐渐升高,K/Rb和K/Cs比值逐渐降低,从Ⅳ带→Ⅴ带,Mg、Ti降低、Li、Rb、Cs、F含量出现突增,其中,w（F）最高可达11.8%、w（Li₂O）可达8.33%,w（Cs₂O）为4.00%,而铯多硅锂云母中的w（Cs₂O）可达18.0%。这些证据均表明,5号脉具有极高的分异演化程度,从外部带向核部演化程度逐渐增高;Ⅳ带云母的突变很可能暗示其经历了岩浆-热液过渡过程,而Ⅴ带主要发育于热液阶段,此时的流体性质有利于Nb、Ta尤其是Ta元素的富集再沉淀。仁里矿床经历了岩浆-热液2阶段成矿作用,并且稀有金属的成矿很可能持续至热液阶段,这也是造就它特殊性（高品位）的重要原因。更多还原

【Abstract】 The No. 5 pegmatite from Renli high-grade superlarge pegmatite-type Nb-Ta polymetallic deposit is the most enriched ore-bearing pegmatite vein with remarkable zoning in the area. Micas exist in each zone as a pentrating mineral and present a variety of changes in composition and structures from the external zone to the internal zone. In this study, we conducted a detailed electron probe analysis(EPMA) on the micas from different zones of No. 5 pegmatite, investigated the characteristics of the micas through their evolution. Following informations have been obtained: Mica types changes from white mica to lepidolite inward the pegmatite vein, Ⅰ→Ⅲzones are dominated by white mica, lithium micas started to show up from zone Ⅳ and meanwhile bagan to develop a variety of disequillibirum and replacement structures; Li, Rb, Cs, F, Mg, Ti content continously increased from zone Ⅰ to zone Ⅳ, and K/Rb and K/Cs ratio gradually reduced; from zone Ⅳ to zone Ⅴ, the content of Mg, Ti decreased, whereas Li, Cs, F rapidly increased and reach a maximum value of 8.33%, 4.00% and 11.8%,respectively. These evidences illustrate that No.5 pegmatite is an extremely highly fractioned vein which formed from the edge to the core during fractional crystallization; the sudden convert in chemical composition and mica types in zone Ⅳ is likely to be generated under a magmatic-hydrothermal transition environment, zone Ⅴ is characterized by a hydrothermal stage of magma evolution while the exsolution fluid properties might be favorable for Nb, Ta, especially Ta enrichment and re-precipitation. Therefore, we propose that the Renli deposit underwent two stages of mineralization—magmatic and hydrothermal stages of evolution, and the mineralization of rare metals probably continues into the hydrothermal stage, which is the reason for the output of high-grade Ta ore by Renli deposit.更多还原