Orogen Response to Changes in Climatic and Tectonic Forcing

Abstract

Despite much progress, many questions remain regarding the potential dynamic coupling between atmospheric and lithospheric processes in the long-term evolution of mountain belts. As a complement to recent efforts to discover the interrelationships among climate, topography, erosion, and rock deformation under conditions of mass-flux steady state, we explore orogen response to changes in climate and tectonic influx. We derive an analytical model that predicts a powerful climatic control on orogen evolution and distinct, potentially diagnostic, responses to climatic and tectonic perturbations. Due to isostatic compensation, the near-surface rock uplift rate during transients is tightly coupled to climate-modulated erosional efficiency. System response is approximately exponential, with a characteristic response timescale that is inversely proportional to the climate- and lithology-modulated erosional efficiency, and is largely insensitive to initial conditions, tectonic influx, and both the sign and magnitude of perturbations.