Evidence for the episodic erosion of the Medusae Fossae Formation preserved within the youngest volcanic province on Mars

Abstract

We use orbital SHAllow RADar (SHARAD) sounder data to three-dimensionally visualize the subsurface structure of Elysium Planitia, the youngest volcanic province on Mars. Our results reveal an emplacement history consisting of multiple groups of overlapping lava flow units, originating from different sources. The uniquely complex "radar stratigraphy" of Elysium Planitia, relative to other volcanic regions, requires a distinct mechanism to generate the numerous reflectors observed in SHARAD data. Sedimentary deposits interbedded with successive batches of lava flows could account for the elaborate pattern of reflectors. We infer that widespread, rapidly emplaced material sourced from the enigmatic Medusae Fossae Formation (MFF) creates these sedimentary layers. This implies that episodes of atmospheric activity, perhaps linked with the obliquity of Mars, periodically Erode and redeposit material from the MFF across a large region.