On the possibility of convection in the Venusian crust

Abstract

We evaluate the possibility of convection in the Venusian crust by utilizing recently developed scaling laws for the onset of convection in temperature- and stress-dependent viscosity fluids, heated from below or from within. We find that crustal convection can occur within plausible ranges of surface heat flux, crustal thickness, and rheologies. Crustal convection can occur at subsolidus temperatures if the grain size is less than 0.1 mm and the crust is relatively thick, close to the gabbro-eclogite transition. For larger grain sizes, particularly where deformation occurs through dislocation creep, crustal convection is likely to occur only at supersolidus temperatures. If crustal convection does occur in the Venusian crust, it would increase heat transport efficiency in the crust and affect the interior dynamics and evolution of the planet. It would also generate thermal variations within the crust that would affect the constraints on the elastic thickness and the heat flux from gravity and topography data analysis. Further investigation of the two-phase dynamics of a partially molten crust is essential for a better understanding of crustal convection and accurate interpretation of surface observations.