Geodynamics of Venus: Difference between revisions

The global distribution of impact craters that was discovered by the Magellan mission to Venus has led to numerous theories on Venusian resurfacing. Phillips et al. (1992) developed two conceptual end-member resurfacing models that describe the distribution of impact craters. The first end-member model suggests that a spatially random distribution of craters can be maintained by having short-duration resurfacing events of large spatial area that occur in random locations with long intervening time intervals. A special case of this end-member would be global resurfacing events; for this case one would be unable to tell from the current surface whether the last global event was part of a recurring cycle or a singular event in the planet's history. The other end-member is that resurfacing events that wipe out craters are of small spatial area, randomly hi distributed and frequently occurring. [[File:Venus Dickinson Crater.jpg|thumb|right|x300px|The image is approximately 185 kilometers (115 miles) wide at the base and shows Dickinson, an impact crater 69 kilometers (43 miles) in diameter. The crater is complex, characterized by a partial central ring and a floor flooded by radar-dark and radar-bright materials. The lack of ejecta to the west may indicate that the impactor that produced the crater was an oblique impact from the west. Extensive radar-bright flows that emanate from the crater's eastern walls may represent large volumes of impact melt, or they may be the result of volcanic material released from the subsurface during the cratering event.]]