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B. M. Jakosky, M. T. Mellon, N. E. Putzig, B. M. Hynek, N. Murphy, S. Martinez-Alonso (Univ. of Colorado), S. M. Pelkey (Brown Univ.), P. R. Christensen, R. L. Fergason (Arizona State Univ.)
In order to determine the global distribution of surface materials on Mars, we can combine globally distributed measurements made from orbit with detailed in situ observations available now at five landing sites on Mars (VL1, VL2, MPF, Spirit, Opportunity). Key remote-sensing observations that cover a large fraction of the planet include thermal-infrared temperature measurements (from which thermal inertia is derived), radar reflectivity (density and roughness), imaging at scales from meter to tens of meters (geological context and surface structure), and topography. We have direct observations at the five landing sites of unconsolidated materials ranging in size from fine-grained dust to coarse-grained particles, rocks ranging in size from cm to m and larger, and cemented or indurated materials that span a wide range of friability and cohesiveness. In particular, variations in dust abundance, particle size, and degree of induration, in different combinations in different places, control surface structure. While one can view the surface as consisting only of these various components, mixed and matched in different proportions, this ignores the geological context which controls the surface structure. Evidence is seen for specific processes at the landing sites and as observed from orbit, including aeolian deposition and erosion, aqueous processes, and physical weathering from a number of mechanisms. In combination, we have a powerful tool for deriving surface properties; these can be used to determine the processes that occur globally and to infer characteristics of future potential landing sites.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.