An intensive study of impact craters to "probe" and "gauge" the complex geologic history of Mars and to further understand cratering as a formative process on terrestrial bodies

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Impact cratering is the most ubiquitous geologic process acting on solid planetary surfaces throughout the solar system; thereby, it played a significant role in the early formation, modification and in some cases the aqueous alteration of planetary crusts. Mounting observational evidence supports that impact cratering has not only physically modified the rocky surfaces of Earth and Mars but may have also played a significant role in the evolution of early life and facilitated the concentration of resources. The study of impact craters may be used to elucidate the complex geologic history of the planetary bodies that host them. Craters are generally consistent morphologically, making them one of the most easily recognized features on planetary surfaces. As such, they are also useful as natural "gauges" sensitive to and recording the effects of the geologic processes that modify them over time. Impact craters are classified by their general morphology and morphometry into simple, transitional, complex, which has been determined to be controlled by the size of the crater, gravity of the body and the strength of the target materials in which it formed. Furthermore, craters effectively excavate, uplift and expose subsurface rocks that may not otherwise be exposed at the surface by other processes (particularly on Mars where plate tectonics is lacking). Thereby, craters that are well-exposed act as natural "probes" of the composition, stratigraphy and structure of shallow to deep interiors of planetary bodies. The proposed research program focuses on the identification and intensive study of the best-preserved and -exposed craters on Mars and an analysis, synthesis and interpretation of orbital visible, spectral, thermophysical and elevation data sets covering them. The best-preserved impact craters provide the clearest observations and insights into various aspects of the cratering process; furthermore, they will continue to provide a baseline for studies of erosion and deposition (i.e., degradation) on Mars. A study of the best-exposed complex craters, focusing on ejecta, crater wall/terraces, central structures, etc., will provide information on the composition, rheology/strength and structure of various levels of the shallow to deep subsurface. The proposed research will continue to expand on our knowledge on the impact processes, and their usefulness as a natural "tool" for elucidating other processes that have and continue to act on planetary bodies. Although the emphasis of this research program is not specifically terrestrial-based, the data and methods employed here are similar to those utilized by exploration geology, geophysics, and environmental remote sensing, and even includes image analysis techniques used for national defense. As such, HQP involved in this research program will learn fundamental skills that are directly applicable to other fields.