Stream Profile Adjustment to Crustal Warping: Nonlinear Results from a Simple Model

Three numerical experiments have been performed, modeling response of a greatly simplified stream system to initiation of crustal tilting and domal uplift. Model results show signs of nonlinear behavior in varying degrees. These signs include river profile adjustments that have forms quite different from the geometries of crustal movements, cases of channel erosion following deposition at the same location, and spatial transition points between opposing adjustments (i.e., erosion and deposition) that fail to coincide with boundaries or axes of crustal movement. Particular nonlinear effects wax or wane as the system adjusts to a new, dynamic equilibrium with the continuing crustal movement. The modeled features of stream adjustment are not in so extreme a class as the commonly discussed complex response of fluvial systems, but they do serve to suggest some caution in studies that employ stream profile information as an indicator of crustal movement.