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R. Greeley, J.E. Bleacher, S.R. Cave, D.A. Williams (Arizona State University), S.C. Werner, G. Neukum (Free University, Berlin), HRSC Co-Investigator Team
Recent High Resolution Stereo Camera (HRSC) images from the ESA Mars Express orbiter reveal an apron-shaped volcanic terrain covering 75,000 square km on the south flank of Pavonis Mons. This terrain developed from eruptions along a prominent rift zone, leading to the formation of >31 individual ``low" shields and various fissure flows which, collectively, form a relatively flat plain sloping less than 1 degree away from Pavonis Mons. Individual low shields range in size from a few km to nearly 35 km across, with the flanks of the smaller shields being covered by younger flows from other vents. Fissure-fed flows fill the areas between the low shields, helping maintain the low relief of the volcanic apron. Many of the shield and fissure flows were emplaced through lava tubes and channels. Preliminary crater counts on one small shield located at 6.5 S, 246.7 E yield cratering model ages between 100-500 Ma, suggesting that at least some of this volcanism was geologically recent. The characteristics of the features on the volcanic apron are analogous to the ``plains" style of volcanism seen on Earth, and are interpreted to represent a transition from the shield-building volcanism of Pavonis to the surrounding volcanic terrain of the Tharsis uplands.
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.