Response of a steady-state critical wedge orogen to changes in climate and tectonic forcing

Abstract

The theories of critical orogenic wedges and fluvial erosion are combined to explore the interactions between tectonics, erosion, and climate. A model framework is developed which allows the derivation of an exact analytical scaling relationship for how orogen width, height, and rock uplift rate vary as a function of accretionary flux and precipitation rate. Compared to a model with prescribed uplift rate, incorporating the tectonic response introduces a powerful negative feedback on the orogen, which strongly damps the system's equilibrium response to changes in forcing. Furthermore, for the most commonly assumed forms of the fluvial erosion law, the orogen is more sensitive to changes in the accretionary flux than in the precipitation rate. And while increases in accretionary flux and precipitation rate both cause an increase in exhumation rate, they have opposite tendencies on the orogen relief. Further analysis shows that the pattern of rock uplift does not affect the scaling relationship and that it is only weakly dependent on the hillslope condition.