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自然界绿柱石存在三个类质同象系列.即“八面体”绿柱石(c/a=0.991~0.996)·“正常”绿往石(c/a=0.997~0.998)和“四面体”绿柱石(c/a=0.999~1.003)。绿柱石矿物精细结构研究表明,二公阳离子置换八面体中Al,Li置换四面体中Be,而碱离子被绿柱石通道所容纳,用于补偿低价阳离子置换Al八面体和Be四面体引起的电价不足。伟晶岩绿柱石通常含有>1.6Wt%的通道水,而包裹体中流体仅为0.15Wt%左右。室温下绿柱石通道中存在Ⅰ型和Ⅱ型H2O,其H-H矢量分别垂直和平行于c轴。由于高温脱水(T>800℃)过程绿柱石通道水氢同位素无明显分馏效应,因此通道水代表绿柱石矿物形成时的原生水。现有的研究表明.绿往石通道水δD和流体包裹体水δD具有显著差异。利用绿柱石通道水测定岩浆水的氢同位素组成.可避免流体包裹体测定δD值因多个世代包裹体污染而引起地质含义的不确定性。无疑,它将是一种了解岩浆-热液过渡阶段性质、定量示踪伟晶岩挥发分演化(主要H2O)以及伟晶岩成因等的强有力工具。
There are three types of isomorphism in nature. “Octahedral” beryl (c / a = 0.991-0.996), “normal” greenstone (c / a = 0.997-0.998) and “tetrahedron” a = 0.999 to 1.003). The fine structure of the beryl mineral shows that the divalent cation replaces Al in the octahedron and the Li replaces Be in the tetrahedron, while the alkali ions are contained in the beryl channel to compensate for the substitution of the low-valent cation with the Al octahedron and the Be tetrahedron Price is not enough Pegmatite usually contains> 1.6Wt% of channel water, while the fluid in the inclusion is only about 0.15Wt%. At room temperature, type I and type II H 2 O exist in the beryl channel, and their H-H vectors are perpendicular and parallel to the c-axis, respectively. Channel water represents primary water at the time of the beryl mineral formation because there is no apparent fractionation effect of hydrogen isotopes in the beryl channel due to high temperature dehydration (T> 800 ° C). Existing research shows. There is a significant difference between δD in green-stone channel and δD in fluid inclusions. Determination of Hydrogen Isotope Composition of Magmatic Water Using Beryl Channel Water. Fluid inclusions can be used to determine the uncertainty of the geological significance of δD values caused by contamination of multiple generations of inclusions. Undoubtedly, it will be a powerful tool to understand the nature of the magmatic-hydrothermal transitional stage, quantitatively trace the evolution of pegmatite volatiles (major H2O), and the genesis of pegmatites.