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应用透射电子显微镜(TEM)详细研究了含柯石英榴辉岩、石英榴辉岩及石榴角闪岩中石榴石的塑性变形特性。研究结果表明,石榴石在榴辉岩和角闪岩相变质条件下,发生了强烈的塑性变形。在含柯石英榴辉岩、退变榴辉岩及石榴角闪岩中,石榴石的超微构造特征存在明显的差异。在含柯石英榴辉岩中石榴石的位错密度(ρ)比在角闪岩中者低。用石榴石位错密度估算了相对差异应力值,并讨论了在超高压榴辉岩形成和退变质过程中各阶段的变质条件。根据石榴石位错密度测定的差异应力,与用岩石学和构造地质学观点推论的超高压榴辉岩形成和折返的地质环境是吻合的。
Transmission electron microscopy (TEM) was used to investigate the plastic deformation behavior of garnet in coesite-bearing eclogite, quartz eclogite and amphibolite. The results show that the garnet undergoes intense plastic deformation under eclogite and amphibolite facies metamorphism. In coesite-bearing eclogite, retrograded eclogite and garnet amphibolite, the ultrastructural characteristics of garnet are significantly different. The dislocation density (ρ) of garnet in coesite-bearing eclogites is lower than in amphibolite. The relative difference stress values were estimated by using the dislocation density of garnet and the metamorphic conditions at various stages during UHP eclogite formation and retrogressive metamorphism were discussed. The differential stress determined by the garnet dislocation density is in agreement with the geologic setting of the eclogite eclogite that was deduced from the petrologic and tectonic geology point of view.