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本文应用光学显微镜、透射电子显微镜和阴极发光显微镜系统研究了 Waterberg断层带 (纳米比亚 )内粗晶大理岩中发育的构造岩。宏观碎裂结构与微观糜棱状结构是断层构造岩的主要特点。巨大的变形碎屑与弥漫的细小颗粒基质形成了鲜明的反差。广泛发育的压溶缝合线与多阶段方解石细脉遍布构造带不同部位。TEM亚微分析表明 ,细粒基质是由粗大碎屑经过亚颗粒旋转 ,并伴随着局部颗粒边界迁移形成的动态重结晶颗粒。虽然亚颗粒粒度具有简单的峰值分布 (～ 0 .3～0 .4μm) ,但动态重结晶颗粒的粒度却具有较大的变化范围 (0 .1～ 3.0μm )并具有多峰值分布的趋势。 TEM亚微结构 (晶格位错结构 )分析与亚颗粒、动态重结晶粒度、变形双晶宽度统计分析充分证明变形—恢复过程的非稳态特点。结合阴极发光分析阐明在上部地壳环境中 ,方解石大理岩经历脆性变形过程中 ,流体相广泛介入到变形作用中 ,并促进岩石的非稳态脆 -韧性转变与低温塑性的出现。促进位错活化与迁移和恢复作用发生的水解弱化机理合理地解释了上部地壳层次大理岩的低温塑性
In this paper, the tectonic rocks developed in the coarse-grained marble in the Waterberg fault zone (Namibia) were studied using light microscopy, transmission electron microscopy and cathodoluminescence microscopy. Macroscopic and microscopic mylonitial structures are the main features of fault tectonic rocks. Huge deformation crumbs and diffuse small granular matrix in sharp contrast. Widely developed pressure solution suture and multi-stage calcite veins throughout the tectonic zone with different parts. TEM submicroanalysis shows that the fine-grained matrix is a dynamic recrystallized grain formed by the coarse clastic through the rotation of sub-grains accompanied by the migration of local grain boundaries. Although the sub-particle size has a simple peak distribution (-0.3 ~ 0.4 μm), the particle size of the dynamically recrystallized particles has a wide range of variation (0.1-1.0 μm) and has a multi-peak distribution. TEM submicroscopic structure (lattice dislocation structure) analysis and sub-particles, dynamic recrystallization grain size, deformation twin width statistical analysis fully demonstrated the deformation-recovery process unsteady characteristics. Combined with cathodoluminescence analysis, it is clarified that in the upper crust environment, the fluid phase interpenetrates extensively into the deformation during the brittle deformation of calcite marble and promotes the occurrence of brittle-ductile transition and low-temperature plasticity of rock. The mechanism of hydrolytic weakening that promotes dislocation activation and migration and recovery plays a reasonable role in explaining the low-temperature plasticity of the upper crustal marble