西南天山榴辉岩的显微构造及其变形机制探讨  

The Microstructure and Deformation Mechanism of Eclogite in the Southwestern Tianshan,Xinjiang

作　　者：查明高[1] 熊贤明[1] 

机构地区：[1]贵州大学资源与环境工程学院,贵州贵阳550025

出　　处：《贵州大学学报（自然科学版）》2015年第3期46-51,共6页Journal of Guizhou University:Natural Sciences

基　　金：国家自然科学基金项目资助(40962003)

摘　　要：岩石、矿物的显微构造是岩石变形、变质等各种地质作用最直观的记录。新疆西南天山高压变质带中榴辉岩的显微构造研究,对认识其在地壳深俯冲过程中的岩石、矿物变形机制有十分重要的意义。西南天山榴辉岩的显微构造研究发现:绿辉石的动态重结晶亚晶粒化和颗粒边界迁移、云母的扭折和波状消光、方解石的机械双晶等显微变形现象,表明动态恢复作用、位错滑移和位错攀移为主的晶质塑性变形机制是榴辉岩的主要变形机制;石榴子石呈无变形刚性特征,具有变斑晶包迹结构,说明固态物质扩散迁移是榴辉岩的另一个重要变形机制;石榴子石多具有良好的晶型,说明石榴子石是在静变质状态下稳态生长而成,这与大别—苏鲁高压—超高压变质带有明显区别。因此,笔者认为位错蠕变、动态重结晶主导的晶质塑性变形和固态物质扩散迁移组合的显微构造变形现象,是西南天山高压—超高压变质榴辉岩的显微构造组合特征。这样的组合特征可能代表了洋壳深俯冲经历高压—超高压变质作用榴辉岩变形机制。The microstructure of rocks and minerals is the most intuitive record,in a variety of geological processes. The microstructure study of eclogites in southwestern Tianshan is very important to the exploration of subduction crust. The microstructure study of eclogites in southwestern Tianshan finds： mechanical twinning and other microscopic dynamic omphacite recrystallization sub grain and grain boundary migration,mica kink and wavy extinction,calcite and deformation phenomenon,show that dynamic recovery effect,dislocation glide and climb of dislocation based crystal plasticity deformation mechanism is the main deformation mechanism. Eclogite; garnet showed no deformation rigidity characteristic,has the porphyroblast envelope structure,description of solid matter diffusion migration is another important deformation mechanism of eclogite; garnet has the crystal type of good,says Akashi garnet is in static state of steady growth and metamorphism,the and the Dabie Su Lu HP-UHP metamorphic with significant difference. The author thinks,dislocation creep and dynamic recrystallization dominated crystal plastic deformation and solid matter diffusion migration combination of microstructural deformation phenomenon,is the combination of microstructure characteristics of southwestern Tianshan HP-UHP metamorphic eclogite. This combination of features may represent a deep subduction of oceanic crust experienced high and ultra high pressure metamorphism of eclogite deformation mechanism.

关 键 词：西南天山 榴辉岩 显微构造 变形机制 

分 类 号：P313[天文地球—固体地球物理学]