Atlantis Chaos

This HiRISE image covers a small area within a degraded crater adjacent to Atlantis Chaos in the Electris region of Mars. The crater and much of the surrounding region were once extensively mantled by a layer of material(s) of unknown origin and only small remnant outcrops of this material remain seen as flat topped mesas in the image sub-frame shown here. Intervening areas expose ancient uplands materials locally punctuated by narrow ridges that may represent more resistant material within the mantling deposit that were left in relief as the sediments were eroded away. Although the mesas do not appear to be comprised of finely layered materials, hints of some layering in a few locations can be seen. Large blocks of material are being shed from the mesas, but do not appear to accumulate on the mesa slopes as large talus aprons. Some wind blown dunes and ripples can be observed, but are not as widespread as in many other locations imaged with HiRISE. Collectively, these characteristics suggest that the material(s) forming the mantling deposit possess some limited strength, but are easily broken down and removed by wind over time. One possible Earth analog for these deposits may be the wind blown accumulations of very fine sediments, or silt known as loess.