罗布莎豆荚状铬铁矿床中刚玉的含Ti矿物包裹体特征
Characteristics of Titanium-Bearing Inclusions Found in Corundum of Luobusa Podiform Chromitite, Tibet

通过能谱和电子探针分析了西藏罗布莎豆荚状铬铁矿石刚玉中的含钛合金和含钛氧化物包裹体特征，分析发现刚玉中含Ti合金矿物包裹体主要有Ti-N、Ti-B、Ti-C、Ti-Si P和Ti-Si-Fe以及Ti-Al-Zr氧化物.Ti-N合金呈磨圆状、梅花状，粒度约17μm×35μm；Ti-B合金呈长柱状，10 μm×58 μm；Ti-C合金呈自形、他形，粒度约40 μm×50 μm；Ti-Si-P和Ti-Si-Fe合金成分不均一，呈一个熔融体包裹在刚玉中；Ti-Al-Zr氧化物成分纯净.结合铬铁矿石中发现大量的微粒金刚石和碳硅石等超高压异常地幔矿物，提出罗布莎铬铁矿石中的刚玉及其中的特殊矿物包裹体组合形成于高压环境的深部地幔.
The titanium-bearing alloy and titanium-bearing oxide inclusions in corundum collected from Luobusa podiform chromitite in Tibet are studied. The EDS and EPMA analyses show that the Ti-N alloys are rounded or forming a quincunx with the size of 17 μm×35 μm; the Ti-B alloys are long columnar in size of 10 μm×58 μm; the authigenic and exnotopic Ti-C alloys are 40 μm×50 μm; the Ti-Si-P and Ti-Si-Fe alloys occur as highly heterogeneous melt in the corundum and the Ti-Al-Zr oxides are pretty pure in composition. Considering the unusual ultra-high pressure mantle mineral groups like diamond and moissanite recovered from the Luobusa chromitite, it is suggested that the corundum and its special mineral inclusions might form at the high-pressure deep mantle environment