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- Title
Revising the Basal Permittivity of the South Polar Layered Deposits of Mars With a Surficial Dust Cover.
- Authors
Grima, C.; Kofman, W.; Hérique, A.; Beck, P.
- Abstract
Bright basal reflections from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) have been proposed to be consistent with permittivities characteristic of a wet material beneath the south polar layered deposits (SPLD). The characterization of a recently formed impact crater highlight the existence of a several meters thick ice‐poor layer associated to a unit blanketing a large portion of the SPLD. We revise the radar propagation model used to invert the basal permittivity by including a surficial thin layer. We find that the inverted basal permittivity is highly sensitive to the properties of such a layer, with solutions ranging from common dry rocks to an unambiguously wet base. We advocate toward a better characterization of the surficial cover to assess the wet or dry nature for the base, and possibly reconcile most of the literature on the topic. Plain Language Summary: A localized bright radar reflection has been detected from the base of the Southern Martian polar cap. This reflection has been attributed to salty water infiltrating the material present beneath the ice. However, this result is not yet reconciled with other radar analyses and a debate has emerged on how liquid brine could be sustained at Martian conditions. Recently a 5‐m thick layer of dust blanketing the surface of the ice cap has been detected from a recent crater excavation. This layer would act like a thin coating material that alters the apparent property of what is seen through a coated glass. At radar wavelengths, it can significantly modify the basal composition inferred from radar echoes. The bulk property of this layer is still unknown and a better characterization is necessary to inform the debate over a wet or dry base below the ice cap. Key Points: We re‐assess the radar inversion of the south polar layered deposits (SPLD) basal permittivity by incorporating the recently characterized dust layer mantling the iceThe inverted basal permittivity is highly sensitive to the property of the surficial dust layerBetter characterization of the dust layer is necessary in discriminating the nature of the SPLD bright basal reflector
- Subjects
GROUND penetrating radar; PERMITTIVITY; DUST; MARS (Planet); ICE caps; FUSION reactor blankets
- Publication
Geophysical Research Letters, 2024, Vol 51, Issue 12, p1
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2024GL109085