CONVECTION-DRIVEN TECTONICS ON VENUS

An analysis is presented for convective stress coupling to an elastic lithosphere as it applies to tectonic deformation on Venus. The results predict that dynamic uplift of Venusian topography must be accompanied by extensive brittle failure and viscous flow in the lithosphere. Geoid anomalies and geoid-to-topography ratios for Venusian topographic features are large compared to values for thermal swells in Earth's ocean basins; this suggests that dynamic support of topography must be an important process on Venus. Further, a low-viscosity zone is probably not present beneath the Venusian lithosphere. A comparative analysis suggests that tectonic deformation of the lithosphere associated with dynamically supported topography on Earth is unimportant. -from Author