石榴石的塑性变形及差异应力计算

STUDY OF PLASTIC DEFORMATION OF GARNET AND CALCULATION OF FOSSIL DIFFERENTIAL STRESS

岩石在形成时和形成后所经历的任何热力学事件都应在其内部留下痕迹 ,如何寻找和发现这些遗迹是地质学界长期关注和亟待解决的问题。笔者认为 ,电子显微技术 ( TEM)是解决这一问题的最有效、最直观的方法之一。最近几年 ,大量的 TEM研究结果证实 ,各类变质岩中的石榴石均发生不同程度的塑性变形。深入研究其变形程度和变形特征 ,对于揭示岩石所经历的变质变形历史具有重要的意义 ,特别是通过观测位错密度 ,可定性推算岩石曾经历的古差异应力 ,为拟定区域构造演化模式提供佐证。

Any thermal event that has occurred during and after the formation of rocks can be traced in the rocks themselves. How to search these traces has been the focus of geological research in our country for a long time,and it is also a problem that needs to be solved as soon as possible. In recent years,results of studies by transimission electron microscopy (TEM),have shown that garnets occurring in different types of metamorphic rocks have undergone different degrees of plastic deformation.An intensive study on the extent and the characteristics of the deformation will be very useful in disclosing the history of metamorphism and deformation that the rocks have suffered. By determing the dislocation density of garnets one can roughly calculate the ancient differential stress tha the rocks have experienced to provide data for a model of tectonic evolution of the area concerned.