Modeling the complex dynamic interactions between surface processes, crustal deformation and climate change (Invited)
Abstract
Natural landforms evolve in response to tectonic uplift and advection, as well as the distribution and changes in precipitation patterns. Numerous models of these interactions between crustal deformation, surface topography and climate have been developed in recent years, based on (a) a wide range of spatial and temporal discretization methods, (b) numerical algorithms of the basic governing equations and (c) various methods designed to couple the physical processes evolving at a variety of temporal and spatial scales. To illustrate this point we briefly present results of a fully coupled surface processes - thermomechanical model of the Earth crust undergoing oblique compression. We demonstrate the complex interactions resulting from the rotation of the stress tensor associated with loading/unloading by surface processes at the scale of surface topographic features (1 to 10 km), which controls the distribution of the deformation between pure thrust and pure strike slip segments of an actively deforming plate boundary. In many natural systems and especially in tectonically active regions, fluvial erosion sets the pace at which a landscape evolves in response to a given uplift and precipitation rate. Consequently, drainage network organization and evolution is critical in determining the distribution and efficiency of surfaces processes. Most of the existing numerical methods used to discretize landscapes are not adequate to properly track and adjust the geometry of the river network following rapid changes in landform geometry, the distribution of precipitation and/or tectonic horizontal advection. Here we present a new method based on a semi-analytical solution of the equations representing the balance between fluvial incision and tectonic uplift in the vicinity of drainage divides. Our new algorithm also makes use of state-of-the-art numerical methods to (a) compute the rapidly evolving geometry of the river network, (b) estimate contributing drainage area and (c) implicitly solve the stream power-law equation. We present the details of the method and illustrate it through a series of numerical experiments in which drainage divides are forced to migrate in response to changes in precipitation patterns and horizontal tectonic advection.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMEP42A..01B
- Keywords:
-
- 1824 HYDROLOGY / Geomorphology: general