Author(s):
Michael P. Bishop - University of Nebraska-Omaha
John F. Shroder Jr. - University of Nebraska-Omaha
Abstract:
Understanding climate change and the geodynamics of mountain systems requires formal representations of climatic, tectonic and surface processes in numerical models. Progress in this direction has been facilitated with the advent of digital elevation models and advanced computing technology. Landscape-evolution simulations provide new opportunities to evaluate hypotheses regarding polygenetic topographic evolution. To do so, however, requires innovative parameterization schemes that characterize climate-topography-surface process feedbacks. Therefore, we describe and evaluate a one-dimensional hillslope evolution model that is being used to evaluate these interactions in the western Himalaya. The model accounts for simple radiative forcing, orographic precipitation and total rock uplift. Surface processes include weathering rate, regolith transport, bedrock landsliding, and bedrock river incision. Climate and surface process feedbacks are accounted for as precipitation variation governs the weathering rate, sediment transport efficiency and river discharge. A later version will incorporate glacial erosion. Model calibration and validation was accomplished using data from Nanga Parbat. Results indicate that such models can be used to estimate sediment fluxes and valley incision rates, and provide insights into topographic steady state and polygenetic topographic evolution.
