CAJ | 학술논문

包裹体是探究矿物结晶生长过程及其地球化学环境的重要探针,是反演寄主矿物形成机制及形成环境的有效工具。本文采用显微激光拉曼光谱、电子探针和LA-ICP-MS技术对来自湖南沅水流域的24颗宝石级金刚石的包裹体进行了原位分析。结果显示,湖南砂矿金刚石中橄榄岩型和榴辉岩型包裹体比例接近,橄榄岩型和榴辉岩型包裹体可在同一颗金刚石中“共存”；湖南金刚石形成时地幔的温度和压力分别为1109~1237℃和4.05~5.83 GPa,相应的形成深度大致为133~192 km；包裹体成分及组合特征显示,扬子克拉通金刚石的形成环境与华北克拉通金刚石有显著差异,前者的形成与榴辉岩的关系更为密切,暗示有古老的地壳物质参与了金刚石的形成过程。
포과체시탐구광물결정생장과정급기지구화학배경적중요탐침,시반연기주광물형성궤제급형성배경적유효공구。본문채용현미격광랍만광보、전자탐침화LA-ICP-MS기술대래자호남원수류역적24과보석급금강석적포과체진행료원위분석。결과현시,호남사광금강석중감람암형화류휘암형포과체비례접근,감람암형화류휘암형포과체가재동일과금강석중“공존”；호남금강석형성시지만적온도화압력분별위1109~1237℃화4.05~5.83 GPa,상응적형성심도대치위133~192 km；포과체성분급조합특정현시,양자극랍통금강석적형성배경여화북극랍통금강석유현저차이,전자적형성여류휘암적관계경위밀절,암시유고로적지각물질삼여료금강석적형성과정。
Mineral inclusions are important probes to explore the crystallizing process, geochemical environment, and forming mechanism for their host minerals. In-situ microscopic laser Raman spectroscopy, electron microprobe and LA-ICP-MS analysis were carried out on mineral inclusions in 24 gem-grade alluvial diamonds from the Yuanjiang Basin in Hunan province. The results showed that the portions of eclogite- and peridotite-type mineral inclusion assemblages are similar and can be coexist in diamond grains. The calculated temperatures, based on nitrogen aggregation states and their portions, range from 1109 to 1237 ℃, and the forming pressures calculated using Raman barometry range from 4.05 to 5.83 GPa for olivine inclusions in the Hunan diamonds, corresponding to a depth of 133~192 km. Furthermore, the mineral inclusions and assemblages reveal that the Hunan diamonds were formed in a lithospheric mantle environment in the Yangtze Craton, which is distinct from the diamonds from the North China Craton. The Hunan diamonds may be formed in a lithospheric mantle containing abundant eclogite, showing the participation of ancient crustal material in the formation of the diamonds.