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剪切带的类型各个时期研究地壳天然变形的地质学家们都曾注意到,高度变形常限于两边近平行的狭窄带内,这些带通常称为剪切带。断层或脆性剪切带是剪切带的特殊变种,带的两边之间有一明显不连续面,带的两壁几乎未应变,也许有角砾岩化(图1a)。此种断层带通常被认为是在造山应力作用下岩石有限弹性应变制约的脆性破裂。其它类似断层的现象在其两壁显示柔性变形,也许最好称之为脆-柔性剪切带。断层面两边的壁在10米距离内能显示出永久应变(图1b)。以往,将这种
Types of Shear Bands Geologists who study the natural deformation of the crust over various periods have noticed that the height deformation is often limited to nearly parallel narrow bands on both sides, commonly referred to as shear bands. Faults or brittle shear zones are a special variant of the shear zone with a distinct discontinuity between the two sides of the belt. The two walls of the belt are almost unstrained and may have brecciated (Figure 1a). Such fault zones are generally considered to be brittle fractures controlled by the limited elastic strain of the rock under orogenic stress. Other fault-like phenomena show flexible deformation on both walls, perhaps best called brittle-flexible shear bands. The walls on both sides of the fault show permanent strain at a distance of 10 meters (Figure 1b). In the past, this will be