HR: 0800h
AN: P41A-05    [Abstracts]
TI: The Influence of Slope Variations on the Levees of Large Channelized Lava Flows in the Tharsis Region of Mars
AU: * Parcheta, C E
EM: parcheta@hawaii.edu
AF: HIGP/SOEST, 1680 East-West Road, University of Hawaii, Honolulu, HI 96822, United States
AU: Fagents, S A
EM: fagents@hawaii.edu
AF: HIGP/SOEST, 1680 East-West Road, University of Hawaii, Honolulu, HI 96822, United States
AU: Baloga, S M
EM: steve@proxemy.com
AF: Proxemy Research, 20528 Farcroft Lane, Laytonsville, MD , United States
AB: Lava flows in the Tharsis region of Mars extend for hundreds of kilometers over very shallow slopes (<0.1 to 1 degree) and exhibit a variety of morphologies, including prominent leveed lava channels. Such flows are typically greater than 35 m thick, have channels 1 to several km in width, and levees on the order of 1 to 10 km wide; these are extremely large by terrestrial standards, and represent huge magma mass fluxes. The marginal levees can form in a variety of ways, but initial formation conditions are commonly overprinted by channel breakouts or overspills due to unsteady flow processes. Levees and channels consequently have shapes and volumes that are dependent on variations in underlying slope, flow rheology, and effusion rate. The purpose of our study is to examine the effects that small changes in topography have on the morphology of channelized lava flows. To address this issue, we have mapped several large flows in the plains north of Pavonis Mons. Using Mars Orbiter Laser Altimeter (MOLA) profiles co-registered with mosaicked Thermal Emission Imaging System (THEMIS) visible and infrared images, we have acquired channel and levee cross-sectional geometries at multiple locations downflow. In order to link variations in flow morphology with variations in underlying slope, we have developed and applied simple models of levee growth using our data as constraints. We will present a comparison of the different models and discuss our inferences for the downflow evolution of flow rheology.
DE: 5470 Surface materials and properties
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 5499 General or miscellaneous
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly