We incorporate the processes of erosion and deposition in a numerical model to predict the stratal geometries and facies patterns produced during episodic thrusting in a nonmarine foreland basin. The resultant stratigraphic record is characterized by a stairstepped facies package in which each retrogradation of facies (toward the thrust) marks the onset of a thrusting event. The retrogradation of facies coincides with the migration of the forebulge toward the thrust and the generation of an erosional unconformity. In the past, changes in basin wavelength during basin evolution have been interpreted to record viscoelastic relaxation of the lithosphere. This model suggests that changes in basin wavelength are a natural consequence of the interplay between thrust and sediment loading on an elastic lithosphere.
- Geological Society of America