Hydrogen content of sand dunes within Olympia Undae |
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Authors: | W.C. Feldman M.C. Bourke R.C. Elphic J. Bandfield B. Diez |
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Affiliation: | a Planetary Science Institute, 1700 E. Fort Lowell, Suite 106, Tucson, AZ 85719, USA b Oxford University Centre for the Environment, University of Oxford, Oxford, OX13QY, UK c Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545, USA d Centre d'Etude Spatiale des Rayonnements, 9 av. Colonel Roche, 31500, Toulouse, France e Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287-6305, USA |
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Abstract: | Neutron currents measured using the Mars Odyssey Neutron Spectrometer, seasonally varying temperatures measured using the Thermal Emission Spectrometer, and visible images measured using the High Resolution Imaging Science Experiment (HiRISE) are studied to determine the water content and stratigraphy of Olympia Undae. Both the neutron and thermal infrared data are best represented by a two-layered model having a water-ice equivalent hydrogen content of 30±5% in a lower semi-infinite layer, buried beneath a relatively desiccated upper layer that is 9±6 g/cm2 thick (about 6 cm depth at a density of 1.5 g/cm3). A model that is consistent with all three data sets is that the dunes contain a top layer that is relatively mobile, which overlays a niveo-aeolian lower layer. The geomorphology shown by the HiRISE images suggests that the bottom layer may be cemented in place and therefore relatively immobile. |
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Keywords: | Mars, polar geology Mars, polar caps Ices |
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