INFLUENCE OF SYNTECTONIC SEDIMENTATION ON THRUST WEDGES IN ANALOG MODELS

Scaled analogue sandbox models have been used to simulate the growth o f Coulomb thrust wedges that include syntectonic sedimentation during thrusting. Increases in the syncontractional sedimentation rate dramat ically change the shape of the Coulomb thrust edge, decreasing the num ber of thrust slices, the internal shortening, and the critical taper of the wedge. Thrust trajectories change from ramp-flat to sigmoidal w ith increased syncontractional sedimentation. The analogue models show many similarities to thrust-fault geometries in accretionary prisms a nd foreland fold-and-thrust belts in which thrust slices prograded int o basins with active sedimentation.