Anisotropic structures in the lithosphere

Abstract

For a short time constant, the lithosphere may be considered as a rigid elastic layer submitted to tectonic stresses. Non-elastic deformations take place in narrow zones located either at boundaries of the tectonic plates or near fault zones within the interior of the plates. Although not proven, it is not impossible that large horizontal shearing deformations take place in the lower part of the crust (e.g. Meissner and Kusznir, 1987). In such a general framework, preferred orientation of minerals may occur in different locations and seismic anisotropy may show up at different scales as a consequence of oriented geodynamic processes during the formation of the lithosphere or, probably more locally, during later tectonic episodes.