No abstract

Orogenic arcs may be classified based on their kinematic evolution into: (a) primary arcs, whose curvature is inherited from the early stages; (b) oroclines, formed by bending of an initial straight belt and (c) progressive arcs, which acquire their curvature gradually as the arc develops . In addition to arc kinematics, the degree of curvature of their fold-and-thrust belts (external zones) may be conditioned also by the rheological properties and geometry of its detachment layer located at the upper crust. For instance, the detachment layer behavior-brittle or ductile-has been proven to control fold-and-thrust belt vergence (e.g., Agarwal & Agrawal, 2002), whereas depocenters of the detachment-related rock formation localize the salients generation