阿尔泰造山带内韧性剪切带的显微、超显微构造和变形机制

阿尔泰造山带的剪切带中发育大量S-C糜棱岩,其内云母产生云母鱼和扭折构造并发生边界重结晶。长石发生不同性质的系列变形,并以出熔成核为主的动态重结晶为主要变形机制,同时伴有强烈的扩散作用,属Naborrow-Herring蠕变。石英的变形呈条带状并发生完全的旋转和边界迁移动态重结晶。石英晶内变形以位错运动和动态恢复为主,形成亚颗粒构造及动态重结晶,以致产生应变弱化和超塑性变形,定量分析确定的石英变形机制主要为低温幂指数蠕变。

MICROSTRUCTURE, SUPERMICROSTRUCTURE ANDDEFORMATION MECHANISM OF SHEAR ZONES IN ALTAY OROGENIC BELT

The shear zones of Altay orogenic belt have a great deal of S-C mylonites and the minerals of the zones underwent complex deformations. Mica-fish and boundary recrystallization hap- pened to mica grains. Feldspar underwent a series of deformations with different characteristics and their principal deformation mechanism is dynamic recrystallization companied with strong boundary diffusion. The nucleation of their recrystallization is chlefly brought about by means of exsolution. This mechanism belongs to Naborrow-Herring creep. The quartz grains took the shape of ribbon and were recrystallized completely. The recrystallization is dynamic and divided into two types: rational and boundary-migration recrystallization. The dislocation movement and dynamic recovery are the main intracrystal deformation of quartz. The recovery resulted in Subgrain structure and recrystallization which led to strain weakness and superplastic deforma- tion. Quantitative analysis shows that the main deformation mechanism of the quartz is low temperature power-law creep.