运动学涡度及其在湘东雁林寺韧性剪切带中的应用

自然界中的剪切带通常是由简单剪切(simple shear)和纯剪切(pure shear)叠加的一般剪切带(general shear)。运动学涡度(kinematic vorticity)的引入提供了一个定量表示两种剪切成分的工具。通过测量剪切带的运动学涡度,可以清楚的了解一般剪切带中究竟是简单剪切还是纯剪切占优势。本文将运动学涡度的基本理论和极摩尔圆法对雁林寺金矿所在的湘东雁林寺韧性剪切带中所表现的运动学涡度进行测量,得出该韧性剪切带的Wk值为0.6,指示其变形以纯剪切为主,且简单剪切作用应变速率比纯剪切作用的应变速率慢。本文从微观运动学层面揭示了湘东雁林寺韧性剪切带对于雁林寺金矿的形成具有重要的意义。

Kinematic Vorticity and its Application to the Yanlinsi Ductile Shear Zone in Eastern Hunan Province

Abstact:In nature , shear can be decomposed into pure shear component and simple shear component. Kinematic vorticity can quantitatively evaluate the component of simple shear and pure shear. By measuring the kinematic vorticity number (Wk), we can clearly understand that in the general shear zone, the simple shear or pure-shear is dominant shear force. This paper introduces basic theory and several measuring methods of kinematic vorticity number, and measres Wk of Yanlinsi ductile shear zone by polar Mohr constructions. It shows that the Wk is near-ly 0.6, which indicates that the shear zone is exactly exist and dominated by pure shear, and straining rate of sim-ple shear is slower than pure shear. It reveals the important significance of the Yanlinsi ductile shear zone for the Yanlinsi gold deposit formation, in microkinematics.