Shear Zones

Abstract

In general, deformation in rocks is not homogeneously distributed. One of the most common patterns of heterogeneous deformation is the concentration of deformation in planar zones that accommodate movement of relatively rigid wall-rock blocks. Deformation in such high-strain zones usually contains a rotation component, reflecting lateral displacement of wall rock segments with respect to each other; this type of high-strain zone is known as a shear zone. Deformation in a shear zone causes development of characteristic fabrics and mineral assemblages that reflect P-T conditions, flow type, movement sense and deformation history in the shear zone. As such, shear zones are an important source of geological information.