运动学涡度及其测量方法

运动学涡度是从流体力学引入到地质学当中的,主要应用于应变非共轴程度的确定。自然界中的剪切变形通常是纯剪切和简单剪切2个端元复合作用的结果,称为一般剪切,利用运动学涡度(WK)可以定量分析两者间的相对大小。文章介绍了涡度的具体测量方法,即张裂脉中纤维法、旋转残斑法、石英C轴组构与主应变比值的方法、石英C轴组构与斜列颗粒形态的方法等。

The kinematic vorticity number and its measurement

The kinematic vorticity number (W_K),which is introduced into geology from fluid dynamics,is used to measure the degree of non-coaxiality of strain. The shearing deformation in nature,which is called the general shear,can be decomposed into the pure shear component and the simple shear component. The relationship between the simple shear and the pure shear can be analyzed quantitatively by using W_K. The measurement methods ofW_K include the way of veins and fibers,the rotated porphyroblast approach,the method based on the relation between quartz C-axis fabrics and strain ratio,the method based on the relation between oblique grain shape and quartz C-axis fabrics,and the method of ultimate Mohr circle.