绿柱石高温高压相变

PHASE TRANSFORMATIONS OF BERYL AT HIGH PRESSURES AND HIGH TEMPERATURES

利用单元六面顶压机,在≤5GPa 范围内对绿柱石进行了实验研究。结果表明,绿柱石在较低压力和高温下分解为硅铍石、金绿宝石和石英的混合物,在较高压力和高温下分解成硅铍石、蓝晶石和柯石英。前者体积收缩9.3%,后者体积收缩约15%。通过热力学方法计算了下列平衡反应:绿柱石=硅铍石+金绿宝石+5β-石英;2金绿宝石+3α-石英=2蓝晶石+硅铍石;2金绿宝石+3柯石英=2蓝晶石+硅铍石的平衡曲线。

By using a six anvil press, the phase behaviors of beryl at high pressure and high temperature was investigated at pressure up to 5 GPa. Beryl has been found to decompose into the mixture of hpenakite, chrysoberyl and quartz at lower pressures and high temperatures, with a decreasde in zero - pressure molar volume of about 9.3%, and into phenakite and kyanite plus coesite at higher pressures and high temperatures with a decrease in zero-pressure molar volume of about 15%. The phase equilibrium boundaries were calculated by the thermodynamic method for the following reactions:Berly=Phenakite+Chrysobery1+5β-Quartz 2Chrysobery1+3α-Quartz =2Kyanite +Phenakite 2 Chrysoberyl+ 3 Coesite =2 Kyanite+ Phenakite.