Geology of the Mer 2003 “elysium” Candidate Landing Site;

Introduction. The NASA Mars Exploration Rover (MER) Project is considering a landing-site ellipse designated EP78B2 in southeastern Utopia Planitia, southwest of Elysium Mons. This ellipse is centered at 11.73N, 123.96E (planetocentric coordinates) and is 155 km long and 16 km wide, has its major axis oriented N86W, and covers ~1640 km 2. The site appears to be relatively safe for a MER landing site because of its predicted low wind velocities in mesoscale atmospheric circulation models and its thin dust cover and low surface roughness at various scales as indicated by topog-raphic, thermal, and imaging data sets. Here, we assess the geology of the site and environs and discuss the potential science results of a MER investigation to this site. Topographic setting. The MER Elysium site, as expressed in a digital elevation model (DEM) derived from Mars Orbiter Laser Altimeter (MOLA) data, occurs in gently tilted upper slopes of southeastern Utopia Planitia below the highland/lowland boundary (HLB) along northwestern Terra Cimmeria (Fig. 1). Highland rocks appear to be broken up into a wide swath of irregular mesas and knobs known as Nepenthes Mensae. The southeastern edge of Utopia Planitia is defined by Hy-blaeus Dorsa, a series of NNE-trending scarps and ridges forming a topographic divide between Utopia and Elysium Planitiae. The dorsa extend to the broad Ely-sium rise, capped by Elysium Mons. The central basin floor of Utopia occurs some 1400 to 2300 km north of the MER ellipse.