A re-interpretation of the recent stratigraphical history of Utopia Planitia, Mars: Implications for late-Amazonian periglacial and ice-rich terrain

• Main Authors: Soare, R.J., Costard, F., Pearce, G.F., Séjourné, A.
• Other Authors: Dawson College, Dpt of Earth Sciences Ontario, University of Western Ontario (UWO), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Thermokarst
• Online Access: https://hal.science/hal-00675013

International audience Utopia Planitia, one of the great northern plains of the Mars, is a region where landscape modification by cold-climate processes, i.e. glacial and periglacial, is thought to be widespread. In the middle latitudes of this region a metres-thick mantle, possibly comprising an ice-dust admixture, has been reported; the occurrence of putative periglacial landforms such as flat-floored (thermokarst-like) depressions, small-sized (possibly thermal-contraction) polygons and polygon trough/junction pits also has been noted. Recently, some workers have suggested that the location of the putative periglacial landforms in mid Utopia Planitia is synonymous with that of the mantle and that the former evolve as the latter degrades. By contrast, preliminary work by others has proposed that this synonymy is misperceived, for two reasons: first, the putative periglacial landforms often are observed in areas of Utopia Planitia where the mantle is absent; second, in areas where the two landscape types are observed concurrently, the putative periglacial landforms either underlie the mantle and, stratigraphically, must predate the mantle, or they are adjacent to the mantle and at a lower datum of elevation. If the geological evolution of Utopia Planitia is to be constrained properly, then each of these hypotheses must be explored. Towards this end, we have mapped the location and distribution of the mantle and putative periglacial landforms across a broad latitudinal and longitudinal swath of the Utopia Planitia and its margins (∼55°-125°E and ∼30°-60°N). This map incorporates all the relevant images of these features and provides a regional scale of analysis. Previous discussions and/or maps of cold-climate landscapes in Utopia Planitia have been much narrower in latitudinal and longitudinal focus. An evaluation of high-resolution images containing the mantle material and putative periglacial landforms, underpinned by the MOLA-based topographic profiles, comprises a local scale of analysis. This too has not ...