LOESSOID DEPOSITS IN ARGENTINA AND ON MARS
On Mars, the present polar-layered deposits should be considered loess (airfall of both dust and ice). Thick equatorial sequences in Arabia, Memnonia, and Medusa Fossae also resemble loessoid deposits: 1km-3km thick unconformable deposits covering the Noachian cratered highlands [Schultz and Lutz, 1988; Thomson et al. 2011]. Associated features closely resemble those with the polar-layered terrains: pedestal craters, unaffected exhumed terrains (craters), sinuous ridges, and relict deposits (such as crater-filled deposits in Nicholson, Henry, and Gale craters). Such similarities prompted the hypothesis that these antipodal deposits resulted from polar wandering during the Late Noachian [Schultz and Lutz, 1988]. The thickness, long duration, and presence of large pedestal craters within these deposits preclude an origin by brief periods of extreme obliquity. Since 1988, three separate paleomagnetic studies placed paleo-poles at nearly the same locations, while radar sounding found evidence for deeply buried ice beneath the Memnonia deposits [Watters et al., 2007]. Timing requires that ejecta deposits (glasses, breccias, blocks)- and even meteorites - would occur throughout the layers, but post-deposition fluvial transport resulted in antecedent drainage, mudstones, and concentration of poorly transported clastics. Such processes overprint the initial depositional sequence and complicate deciphering its origin as a purely loess (Grotzinger and Milliken, 2011). Hence, this process remains relevant, especially with the ongoing exploration by Curiosity Rover.