新疆阿尔泰可可托海3号伟晶岩脉重钽铁矿研究

重钽铁矿是主要见于高度分馏花岗伟晶岩中的一种罕见的钽矿物。新疆阿尔泰可可托海3号伟晶岩脉中存在的重钽铁矿呈他形，与钽猛矿(因Ta含量的明显差异可分为钽锰矿I和钽锰矿Ⅱ)和铀细晶石共生形成铌钽矿物集合体。钽锰矿I构成集合体的主体，而重钽铁矿与相对富Mn和Ta的钽锰矿Ⅱ紧密共生并分布在集合体的边部。重组铁矿的RTaRTa＝Ta／(Nb Ta)]在0．96—0．99间变化，RMnRMn＝Mn／(Fe Mn)]在0．10—0．2l间变化。铌钽铁矿的共生组合和化学成分特征表明，重钽铁矿是钽锰矿I在非平衡条件下快速结晶后残余亚稳定相出溶的产物。

Tapiolite from the Koktokay No.3 Rare Metal Granitic Pegmatite Dyke, Altai, Xinjiang Autonomous Region

Tapiolite is a rather rare Ta mineral occurring particularly in highly differentiated granitic pegmatites. The occurrence of tapiolite from the Koktokay No.3 granitic pegmatite dyke, Altai, Xinjiang Autonomous Region, is reported in this paper. The tapiolite, as anhedral crystals, is associated with manganotantalite (including manganotantalite I and manganotantalite II) and uranmicrolite, forming Nb Ta mineral aggregate. The manganotantalite I is the main component of the aggregate, whereas the tapiolite associated with the manganotantalite II occurs typically in the rim of the aggregate. R Ta R Ta =Ta/(Nb+Ta)] of tapiolite varies between 0.96 and 0.99, while R Mn R Mn =Mn/(Fe+Mn)] ranges between 0.10 and 0.21. Based on assemblage and compositional feature of Nb Ta minerals, it is suggested that tapiolite was a product of exsolution from the metastable phase which was the remnant of manganotantalite I crystallization under disequilibrium condition.