酸性火山玻璃的脱玻化作用

THE DEVITRIFICATION OF ACID VOLCANIC GLASS

本文阐述了酸性火山玻璃发生脱玻现象后的X射线衍射特征、镜下(偏光及扫描电镜)特征和形貌特征,重点讨论了对酸性火山玻璃脱玻化途径有重要影响的网络结构因素和化学成分因素,最终提出酸性火山玻璃的五种脱玻化途径及相应产物:SiO_2±H_2O纯架状、架状网络→“石英”质;SiO_2+Al_2O_3+H_2O±其它成分架状、层状网络→“伊毛缟石”质;SiO_2+Al_2O_3+K_2O(Na_2O,CaO)架状、层状网络→长石质;酸性火山玻璃(含不同的挥发份)架状、层状、链状网络→粘土质及其它可能的产物;SO_2+Al_2O_3+K_2O(Na_2O)+CaO、FeO、MgO(群聚?)等土挥发份层状、链状网络→绿泥石、辉石、闪石。

This paper explains X-ray diffraction characteristics, change features in polarizing microscope and scanning electron microscope and morphology characteristics of acid volcanic glass that has happened devitrification. Both netword structures and chemical components that influence the devitrification ways of acid volcanic glass are major discuss. 5 devitrification ways of acid volcanic glass and relevant products are final put forward as follows: 1. SiO2±H2O=>pure framework or/and sheet network→quartziferous; 2. SiO2±Al2O3+H2O±others=>frame work or/and sheet network→ imogorite-bearing; 3. SiO2+Al2O3+K2O(Na2O,CaO)=>framework or/and Sheet network→ feldspathic; 4. Acid volcanic glass (different volatile compoments )=> framework, sheet or/and chain network→chayey and other products; 5. SiO2+Al2O3+K2O(Na2O)+CaO、FeO、MgO etc. ± volatile components=> sheet or/and chain network→chlorite, pyroxene or/and amphibole.