DEGRADATION OF ENDEAVOUR CRATER BASED ON ORBITAL AND ROVER-BASED OBSERVATIONS IN COMBINATION WITH LANDSCAPE EVOLUTION MODELING

Exploration of Endeavour Crater’s rim segments by the Opportunity rover, combined with extensive observations from the Mars Express and Mars Reconnaissance Orbiters, provide unique and quantitative insights into the processes that have degraded this 22 km wide Noachian age impact crater. Comparing Endeavour Crater with the nearby, relatively young, and morphologically fresh-appearing 19 km diameter Bopolu Crater suggests that Endeavour experienced significant weathering and fluvial degradation during the Noachian Era. Using Bopolu Crater as the starting topography, the MARSSIM landscape evolution model shows that from an initial period of fluvial degradation, weathering, and diffusion, Endeavour Crater was infilled with ~0.5 km fluvial-deltaic-lacustrine deposits and the crater rim was backwasted by ~0.9 km. This early period of fluvial degradation also formed pediment surfaces on the crater rim. A later period dominated by weathering and diffusion further smoothed the rim segments. The final modeled topography indicates that Endeavour Crater was infilled with ~0.8 km of Burns formation after the major period of fluvial degradation. Since the deposition of the Burns formation, wind erosion has been a dominant process in shaping the crater, forming a central mound and trough in the interior deposits of the crater. Topographic profiles over the interior Burns formation and the exposed rim segments are continuous, and indicative of aeolian excavation and backwasting. Approximately 0.4 km of Burns sediment was stripped from the interior of the crater during this period. Perseverance Valley, which lies between Cape Tribulation and Cape Byron, has been the site of extensive exploration by the Opportunity rover because of its possible fluvial or water-charged debris flow origins. The continuous profile over Perseverance Valley with the Burns formation in the interior of Endeavour indicates that its current exposure is younger than the deposition of the Burns formation. Perseverance Valley is interpreted as being the modern exposure of a deep seated radial fault system that has been continuously eroded into by wind and possibly modified by upwelling ground water.