HR: 1340h
AN: P13B-1296    [Abstracts]
TI: Landform Simulations of Parana Basin, Mars
AU: * Barnhart, C J
EM: barnhart@pmc.ucsc.edu
AF: Earth and Planetary Sciences Univ. of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064,
AU: Howard, A D
EM: alanh@virginia.edu
AF: Department of Environmental Sciences University of Virginia, 291 McCormick Rd, P.O. Box 400123, Charlottesville, VA 22904-4123,
AU: Moore, J M
EM: jeff.moore@nasa.gov
AF: NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035,
AB: A landform evolution model is used to explore scenarios responsible for the late-Noachian early-Hesperian fluvial incision on the South Highlands. Simulation DEMs (Digital Elevation Models) are qualitatively and statistically compared to actual DEMs in order to evaluate working hypotheses. MOLA and THEMIS data sets were used to define and quantitatively investigate the valley networks debouching into Parana Basin in Eastern Margaritifer Sinus, Mars. Evaluation of various hypotheses for erosional processes responsible for observed valley erosion were simulated by MSLM (Mars Simulation Landscape Model developed by Howard). The overarching theme of this study is to compare geomorphic data with simulated models to evaluate the contrast in erosional style between the widespread, less channelized mid-Noachian erosion and the relatively limited, yet strongly focused erosion, fluvial, and otherwise, during the Noachian-Hesperian transition. We analyze specific features by statistical correlation and fitness between the features" morphometry and that of the results of model landscapes evolved under specific processes. The results of these quantitative best-fit analyses guide hypothesis generation and testing. Specifically, we focused on valley network placement, density, and depth of incision. In this work, an "original" topographic DEM for a study region is recreated from the extant topography. Various scenarios for runoff and sediment yield, surface induration, and episodic mantling are then simulated starting from the DEM. Suites of model runs explored the effects of discharge scaling, evaporative controls, emplacement of an indurated surface or capping unit, sediment size, and critical shear stress. Model results were statistically compared in terms of pattern and depth of incision with the extant topography for testing hypotheses for climate driven landform evolution. Specifically, elevation difference histograms, Chi-square analyses, and power spectrums were used to test model fitness. Runs with (1) discharge scaling similar to terrestrially arid to semi-arid environments, (2) modest evaporation rates and (3) an indurated capping unit 5 to 10m thick provide the best statistical and qualitative match to the actual surface. In conclusion, the use of landform evolution models provides insight into both process and timing of the evolution of the cratered highlands of Mars beyond using topographic data alone.
DE: 1825 Geomorphology: fluvial (1625)
DE: 1847 Modeling
DE: 5415 Erosion and weathering
DE: 5419 Hydrology and fluvial processes
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting