Evolutionary history of western Eos Chaos of Valles Marineris, Mars: Insights from morphological characteristics

Abstract

The dynamics of aqueous processes within the Eos Chasma region in the trough of Valles Marineris on Mars have been attributed to a variety of Hesperian-aged landforms. We aim to improve the understanding of the geological characteristics of the western part of the Eos Chaos by investigating the morphological, topographical, and thermo-physical characteristics of the western semi-circular segment of Valles Marineris. The western Eos Chaos is characterized by remnants of an elevated crater rim, a central peak, and a circular boundary. Based on these observations, we infer that the study area is an ancient, highly degraded impact crater. Our observations indicate that numerous geological processes, such as fluvial, tectonic, and aeolian processes, have shaped the landforms. For instance, channels on the slope of the wall with a mean v-index of 0.2 indicate a fluvial origin. The chaotic mounds within the study regions are highly degraded. However, the presence of eroded inselberg peaks above the maximum ponding level of eastern Valles Marineris (–3560 m) suggests that both aeolian and fluvial processes have played a role in the denudation of the impact crater. Furthermore, both aeolian and fluvial processes also influenced the morphological evolution of inselbergs of this impact crater of Eos Chaos. The morphological, topographic, and thermal inertia characteristics of the landforms in the Eos Chaos are similar to those found elsewhere in Valles Marineris. In this study, the impact crater of Eos Chaos is considered a sub-region of Valles Marineris, in which evidence for many past geological processes is preserved. Based on possible chronological markers, we have developed a model that explains the evolution of the Eos Chaos impact crater and its incorporation into Valles Marineris.