Structural anatomy of the Kushtagi schist belt, Dharwar craton, south India—An example of Archaean transpression

The NW–SE trending Kushtagi schist belt in the eastern Dharwar craton records the tectonic consequences of a transpression regime. It was formed due to Late Archaean oblique convergence in the Dharwar craton. This relatively unknown schist belt is characterized by two major episodes of deformation. The dominant D1 deformation forming tight to isoclinal non-cylindrical folds and a regional axial planar schistosity is a consequence of transpression. The transpression-related sinistral shear regime is followed by development of a conjugate set of F2 folds and S2 cleavages that are superimposed on the D1 structures. The maximum shortening direction associated with the F2 folds is NW–SE, which suggests longitudinal compression subsequent to transpression. Riedel shear fractures were developed in the sinistral shear regime and dolerite dykes were emplaced along the conjugate Riedel shear fractures. Intrusive granite bodies within and outside the schist belt were emplaced in the late phase of D1 transpression.