Initiation and propagation of shear zones in a heterogeneous continental lithosphere

Abstract

Continental plates represent rheologically heterogeneous media in which complex finite strain fields may develop due to interaction of plate tectonic processes with intraplate heterogeneities. Such a deformation pattern is displayed by the Borborema shear zone system in northeastern Brazil. It involves continental-scale, curvilinear, E-W trending right-lateral transcurrent shear zones. This strain field results from the compressional deformation of a highly heterogeneous continental lithosphere composed of a stiff domain (craton) and rheologically weaker domains (basins). The interaction between imposed boundary conditions and the internal structure of the plate may give rise to highly heterogeneous strain fields, as exhibited by the Borborema shear zone system, in which intraplate rheological heterogeneities induce the development of branched or sinuous shear zones. -from Authors