Catastrophic Outwash Plains on Earth and Mars: Comparisons from Iceland and Chasma Boreale, Mars

Mid-latitude and polar canyons on Mars may represent catastrophic outflow channels generated by geothermal melting of the cryosphere. Possible terrestrial analogs to the Martian systems exist in Iceland where sub-glacial melting induced by volcanism results in catastrophic outflow and deposition of basaltic material onto sandur surfaces. An analysis of the geomorphology and sedimentology of Icelandic systems is used to make direct comparisons to the Martian systems. Furthermore, remote and laboratory identification of basaltic hydrothermal alteration minerals on Icelandic catastrophic outflow surfaces suggests potential for identification of similar materials in Martian outflow deposits. The sandur plains of southeastern Iceland are dominated by boulder to sand-sized clasts of basaltic lavas, palagonitized tuffs, and palagonitized breccias. Palagonite breccia and tuffs represent the dominant basaltic alteration material and comprise