Alluvial Fan in Icaria Planum, Mars: a MEX HRSC Study

Abstract

Numerous channels of the Claritas-Thaumasia area, such as Warrego Valles, indicate previous water flow activities. At some point, the wide basin (Raitala et al., 2005) of southern Claritas Fossae was filled by water transported from the uplands. After the paleolake reached the level of the lowest barrier valley floor it broke through this western saddle valley and formed a channel from the paleolake into the direction of Icaria Planum. The paleolake and adjoining formations were studied using the Mars Express HRSC data sets. Additional sapping channels connected into the channel from the direction of an old impact crater on the northern side of the saddle valley. In the west, close to Icaria Planum, the channel reached an impact crater and the water broke into it. This temporary crater lake has a delta at the channel mouth. The flow continued further through the western crater rim. The crater floor is lower than the channel neck out of the crater and indicates a paleolake phase. Water was led out from the impact crater into the lowlands of Icaria Planum where it formed an alluvial fan. The flow structures and the alluvial fan units in Icaria Planum are visible in the Mars Express HRSC color data.