新疆阿尔泰库威伟晶岩中绿柱石形成的物理化学条件

THE PHYSICO-CHEMICAL CONDITIONS OF FORMATION OF BERYL IN THE KUWEI PEGMATITE, ALTAY, XINJIANG

本文利用包裹体研究探讨了新疆阿尔泰库威伟晶岩中绿柱石形成时的物理化学条件。绿柱石中包裹体类型主要有二类：含硅酸盐子晶流体包裹体和不含硅酸盐子晶气液流体包裹体。含硅酸盐子晶流体包裹体代表岩浆-热液过渡阶段时的一种超临界流体相。结合显微镜观察和含硅酸盐子晶流体包裹体喇曼探针成分测定，得出绿柱石形成时体系中二氧化碳密度较高，pco2=0．68～0．96g／cm3；盐度很低，NaCl（wt％）=3．21％～3．77％；温度高于480℃，压力约为（1．5～3．7）×108Pa。

The physlco-chemical conditions of formation of beryl have been explored based on inclusionstudies of beryls from the Altay pegmatite, Xinjiang. Two types of inclusions have been found: sili-cate datighter crystal-bearing fluid inclusions and gas-liquid fluid inclusions. The silicate daughtercrystal-bearing fluid inclusions represent a supercritical fluid phase of magmatic-hydrothermaltransitional stage. Based on the studies of the density, salinity, temperature and pressure of forma-tion of inclusions, it is suggested that CO2 density is fairly high, Pco2 = 0. 68~0. 96g/cm3; salinityvery low, NaCl wt % = 3. 21 % ~ 3. 77 %; temperature over 48℃; pressure about 1. 5~ 3. 77 kbarin the system during the formation of beryls.