| Popis: |
The large craters and impact basins that are present on nearly every solid body in the solar system are remnants of a cataclysmic process that excavated, melted, vaporized, and ejected tremendous amounts of material from the surface of the planets. The results of this process of energy release and topographic disruption can be used to derive information about the deep geologic past of the planets. On Mercury, the topography of the melted sheet which forms interior floors of craters > 12 km in diameter, is well preserved and can be measured using the altimetric data from the MESSENGER orbital mission. I use these measurements to place chronologic constraints on the onset and duration of some of Mercury’s large-scale topographic features. On the Moon, the events that formed impact craters measuring over 120 km in diameter were capable of disrupting the crust-mantle boundary. Many of those perturbations have persisted through the billions of years since their formation. The processes that preserve this remarkable topography and the way in which it deforms over time, are poorly constrained due to the lack of observation of geologically recent basin formation events. However, constraints on these processes can be determined using models governed by high resolution gravity and topography data gathered from recent orbital missions to the Moon, as well as data produced by laboratory rheology experiments. I measure and catalog the morphologic characteristics of the lunar basins and develop numerical finite element structural models in order to evaluate hypotheses about the formation of these features and provide new insight into the structural evolution of the Moon’s shallow interior. |
