糜棱岩化过程中矿物变形温度计

Mineral Deformation Thermometer for Mylonitization

对有效确定中—低温下糜棱岩变形温度一直以来都没有比较理想的方法,而在研究韧性剪切带过程中对其变形温度的确定又常是必不可少的。根据近年来国际上对天然石英、长石、方解石等矿物变形的研究成果,总结了利用矿物变形指示变形温度的方法。在不同的温度条件下,长石与石英的变形方式具有阶段性,其变形与动态重结晶型式与温度具有明显的对应关系。石英变形中的滑移系及其C轴组构图主要受变形温度的控制。低温变形中的方解石e双晶纹形态也与温度呈密切的相关性。观测这些矿物变形的显微构造,可以很好地估计韧性剪切带糜棱岩化过程中的变形温度。

There has been no ideal means to constrain deformation temperatures of mylonites developed under low-moderate temperature conditions. However, it is necessary to determine the deformation temperature in studies of ductile shear zones. Based on new research achievements about the deformation of minerals, such as feldspar, quartz and calcite, this paper summaries approaches for estimating deformations temperatures by mineral deformation phenomena. Under different temperature conditions, deformations of feldspar and quartz show different stages, and their deformation and types of dynamic recrystallisation are closely related to temperatures. Slip systems and Caxis patterns of quartz as well as calcite e twin also exhibit differences with increasing temperatures. Microstructures of the minerals in mylonites can be used as thermometers to determine deformation temperatures.