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Tectonic-Geomorphologic Modeling of Paleo-Landscapes in Rifts

Abstract

We use tectonic-geomorphologic numerical models to predict paleo-landscape development and sediment deposition in rift zones. Crustal block movements and slip on faults during rift opening cause tectonic topography of the surface, which is then modified by erosion, sediment transport, and sediment deposition in depressions. A simple forward stratigraphic model predicts sediment facies, compaction and permeability. The models are first tested in the Rio Grande rift zone in the southwestern U.S. Characteristic features of this rift include a late Miocene-Pliocene rift-wide unconformity, and the change in drainage system from internally drained basins to a through-going river system (the Rio Grande). Paleo-landscapes form by interaction of climate, erosion, sediment transport and tectonics, and the models are used to understand the relative importance of these factors as well as effects of temporal changes. The fully coupled stratigraphic component of the model provides insight into the relative roles of these factors in the stratigraphy of a narrow continental rift.