Equatorial locations of water on Mars: Improved resolution maps based on Mars Odyssey Neutron Spectrometer data

摘要

We present a map of the near subsurface hydrogen distribution on Mars, basedon epithermal neutron data from the Mars Odyssey Neutron Spectrometer. Themap's spatial resolution is approximately improved two-fold via a new form ofthe pixon image reconstruction technique. We discover hydrogen-rich mineralogyfar from the poles, including ~10 wt. % water equivalent hydrogen (WEH) on theflanks of the Tharsis Montes and greater than 40 wt. % WEH at the MedusaeFossae Formation (MFF). The high WEH abundance at the MFF implies the presenceof bulk water ice. This supports the hypothesis of recent periods of highorbital obliquity during which water ice was stable on the surface. We find theyoung undivided channel system material in southern Elysium Planitia to bedistinct from its surroundings and exceptionally dry; there is no evidence ofhydration at the location in Elysium Planitia suggested to contain a buriedwater ice sea. Finally, we find that the sites of recurring slope lineae (RSL)do not correlate with subsurface hydration. This implies that RSL are not fedby large, near-subsurface aquifers, but are instead the result of either small(less than 120 km diameter) aquifers, deliquescence of perchlorate and chloratesalts or dry, granular flows.