The geomorphologic responses to hinge migration in the fault-related folds in the Southern Tunisian Atlas

In kinematic models of fault-related folds hinges must be mobile during fold growth, yet hinge migration has been rarely demonstrated in nature. Several complementary and independent geomorphological responses are presented here that indicate fold hinge migration in the Southern Tunisian Atlas. The deformation of the overlying Quaternary pediment suggests recent migration of the forelimb synclinal hinge as predicted by the Rafini and Mercier model. The uplift of the first order transverse drainage network, the poor maturation and shallow incision features of limb drainage networks toward the base of the limb slope suggest that new and un-eroded material was regularly uplifted from the down-slope, flat plains as predicted by the fault-propagation fold model.