Venus Was Catastrophically Resurfaced by Volcanoes

Monte Carlo models of the interaction between impact cratering and volcanic resurfacing on Venus: The effect of the Beta-Atla-Themis anomaly

Authors:

1. I. Romeo (a)

Affiliation:

a. Departamento de Geodinámica, Universidad Complutense de Madrid, C/ José Antonio Novais 12; CP-28040 Madrid, Spain

Abstract:

Detailed Monte Carlo models of the interaction of impact cratering and volcanic resurfacing, which included the Beta-Atla-Themis (BAT) volcanic concentration, were used to test different planetary resurfacing histories. The results were compared with: 1) the randomness of the spatial distribution of craters, 2) the number of modified craters, 3) the number of dark-floored craters due to volcanic flooding, 4) the frequency-area distribution of volcanic units, 5) the frequency-size distribution of craters and modified craters, and (6) the spatial distribution of craters and modified craters with respect to the BAT anomaly. Two catastrophic and two equilibrium resurfacing models were tested. The two catastrophic models consisted of one with a drastic decay and the other with a moderate decay of volcanic activity following the catastrophic event. The two equilibrium models consisted of one with a gradual decay of volcanic activity at the end of the model and the other with a magmatic event followed by a gradual decay of volcanic activity. Both equilibrium models and catastrophic model with moderate decay fail to reproduce the small reduction of the crater density in the BAT area. The model that best fits all the observations is a global catastrophic resurfacing event followed by a drastic decay of volcanic activity. Thus, a Venus global catastrophic resurfacing event erasing all previous craters with little post-resurfacing volcanism is supported by this study.