Thrust Fault

Abstract

Thrust fault and its classification is described. Formation of normal and reverse drags is explained in terms of frictional effects along the thrust surface. Flat and ramp, and smooth trajectory thrusts are illustrated along with the associated cleavage patterns. Evolution of planar and listric faults is depicted in an inverted basin. A new model is proposed for development of duplex structures. Decollement upwarps have been identified in the foreland basin of the Himalaya and a model is proposed for their evolution. The model implies that formation of upwarp structures inhibits displacement along basal decollements. Formation of oblique thrust ramps and associated structures are highlighted. A new model, called as basement wedge klippe model, is proposed for formation of klippe structure. Problems related to restoration of deformed sections are described. An unrestorable section does not mean a wrong construction. The thin-skinned model for evolution of fold and thrust belts may not be universally applicable to all the orogenic belts.