Salt tectonics driven by sediment progradation: Part I—Mechanics and kinematics

Abstract Using conceptual reasoning and results from physical models, we describe the mechanical and kinematic characteristics of sediment wedges spreading seaward above a viscous evaporitic layer. Spreading can occur if the distal sediment overburden is thin and weak, or if it comprises preexisting salt bodies. Spreading is accommodated by proximal extension and an associated rise of diapiric ridges, by midslope seaward translation, and by distal shortening. Rapid sediment progradation can lead to the reactivation of older distal folds by later extension. Either retrogradation or renewed sedimentation following a long depositional hiatus can reactivate older grabens and diapirs in shortening.