Modelling the cratering record of Venus

Abstract

The images of the surface of Venus returned by the Magellan spacecraft show a cratering record unlike any other in the solar system. Multiple models of the geologic history of Venus have been proposed to explain this cratering record, including the "equilibrium resurfacing" model and the "global resurfacing" model. I use a two-dimensional Monte Carlo simulation of crater emplacement and volcanic resurfacing to determine what sorts of cratering records would in fact be produced by these models. The equilibrium resurfacing model fails to produce a cratering record resembling the observations. The global resurfacing model requires the specification of post-global resurfacing event history before it can be simulated by this program, but following appropriate specification, it did reproduce the observed cratering record. The global resurfacing model is thereby found to be a more satisfactory model than the equilibrium model. The length of the tail end of the global resurfacing event is found to be of the order of 100 million years, subject to uncertainty in the impactor flux at Venus. The fraction of the planet resurfaced after the end of the global resurfacing event is found to be roughly 15-20%.