Study of a 15 Km Crater with Diverse Morphology, Elysium Planitia, Mars

Introduction: The recent missions to Mars with diverse instruments have provided a new perspective for the study of Martian surface landforms. They have permitted the characterization of over 40,000 impact craters ≥ 5 km in diameter [1], showing a diverse cratering record with some quite unusual morphologies. Changes in crater morphology are thought to reflect the impact energy and target properties involved in the crater formation [2]. We examine the nature of the ~15 km diameter crater (28.3o N, 116.7o E), part of an assessment of rampart craters on northwestern Elysium Planitia (2030o N, 110-120o E) (Figure 1). This crater is of particular interest due to the presence of a massive lobe in the southwestern side of the rim (Figure 2a). Significantly, the Elysium region has been found to contain evidence of widespread ground ice [3]. In addition, lobate ejecta morphology, like that here, has been shown to correlate with evidence of near-surface volatile reservoirs [4]. Perhaps, this feature formed as a result of interaction with ground ice during impact.