HR: 08:00h
AN: P21B-01 INVITED     [Abstracts]
TI: Niveo-aeolian and Denivation Deposits on Mars
AU: * Bourke, M C
EM: mbourke@psi.edu
AF: Planetary Science Institute, 1700 E. Ft. Lowell, #106, Tucson, AZ 85719 United States
AB: Hydrogen abundance data from the Gamma Ray Spectrometer on board the Mars Odyssey platform indicate that large areas of the North Polar Sand Sea have high concentrations (40-60% weight) of hydrogen molecules in the surface deposits. On Earth, cold region sand dunes often contain inter-bedded sand, snow and ice. These niveo-aeolian deposits have unique morphologies and sedimentary structures that are generally not found in warm desert dunes. An atlas of dune niveo-aeolian and denivation features was compiled from published studies of polar deserts on Earth. Features occur at a range of scales and signatures are both morphologic and stratigraphic. The atlas is used to identify similar features on Mars. Examination of high resolution Mars Orbiter Camera images of the North Polar Sand Sea and Southern Crater dune fields have identified several potential signatures of niveo-aeolian and denivation processes on Mars. These include: over steepened lee slopes, cornices, rounded slipface and/or crest, protruding ice cemented beds, alluvial meltwater channels and fans and sublimation avalanches. Other smaller-scale forms probably occur but are not detectable with current resolution data. While these findings have implications for our understanding of martian dune geomorphology, mobility and the geological evolution of the sand seas, they also highlight the potential for a significant volatile reservoir and biological habitat in sand dunes on Mars.
DE: 5462 Polar regions
DE: 5470 Surface materials and properties
DE: 1823 Frozen ground
DE: 1824 Geomorphology (1625)
DE: 1863 Snow and ice (1827)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting