Effects of incompetent units on the formation of geological structures in Kamestan and Payun Anticlines (Zagros)

In folded belts, incompetent units play significant role in folding style and resulting structures. Because of the sensitivity of these units to environmental and tectonical factors, they undergo abrupt variations in thickness and facies. Finally they can control folding mechanism and regional morphology. In the present investigation, two main structures in Payun and Kamestan anticlines in Zagros fold belt were considered. One of them, is gravity collapse structure that commonly takes place in competent units underlain by incompetent units. The other ones, are rabbit ear structures that form on the flanks of main structures. This structures form when a multilayer consisting of lower and upper incompetent units and a middle competent unit undergo a component of layer-parallel shortening during folding