Geomorphology of Eridania Basin, Mars: A Study of the Evolution of Chaotic Terrain and a Paleolake

The Eridania basin in the southern hemisphere of Mars is hypothesized to have contained a large paleolake that has been identified as the source of the large outflow channel, Ma’adim Vallis. Found within the confines of the paleolake boundaries are 5 degraded impact basins which contain concentrations of chaotic terrain, including: Ariadnes Colles, Atlantis Chaos, Gorgonum Chaos, and two unnamed basins. Chaos is typified by accumulations of angular mesas and knobs separated by fractures, which have been interpreted to be the result of subsurface collapse due to breaching of a confined aquifer with a general spatial association to large outflow channels. Chaos within Eridania are not directly related to any outflow features , and also lie at the lowest elevation points within the basins, therefore require a different interpretation for their formation mechanism. We have prepared a geologic map using CTX, HRSC, HiRISE, and MOLA data in order to better understand the history of water, the paleolake, and to constrain models for chaos formation.