VENUS RESURFACING BY CORONAE - IMPLICATIONS FROM IMPACT CRATERS

Coronae, common volcano-tectonic features on Venus, may be actively mo difying the planet's surface. To evaluate the extent of their effects, we compare impact crater densities and proportions of modified crater s out to four radii for Monte Carlo simulations of corona location wit h those fdr two corona classes. We study the Radial Concentric and Con centric Caldera coronae, the two classes believed to represent the you thful and senescent stages of formation, respectively. A high proporti on of tectonized craters and low crater density near Radial Concentric caronae indicate recent activity. Based on the average crater density and propertion of tectonized craters, we interpret Concentric Caldera coronae as old. These results show that tectonism and volcanism is no t limited to the corona interior and carl extend up to four radii from the center.