HR: 0830h
AN: P21B-0052    [PDF]
TI: Searching for Aqueous Mineralogy on Mars Utilizing a Surface Water Flow Model, Mars Global Surveyor and Mars Odyssey Data
AU: * Dalton, J B
EM: dalton@cosmic.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 United States
AU: Sutter, B
EM: bsutter@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 United States
AU: Kramer, M G
EM: mkramer@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 United States
AU: Stockstill, K R
EM: kstockst@utk.edu
AF: Dept. Geological Sciences Univ. Tennessee, 306 Geological Sci. Bldg, Knoxville, TN 37996 United States
AU: Moersch, J
EM: jmoersch@utk.edu
AF: Dept. Geological Sciences Univ. Tennessee, 306 Geological Sci. Bldg, Knoxville, TN 37996 United States
AU: Moore, J
EM: jmoore@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 United States
AB: Studies of Martian surface geomorphology and the recent detection of near-surface water ice by Mars Odyssey gamma ray spectrometer suggest that Mars may have had a water rich past. While 2 to 5 wt.% of carbonate has been detected in the Martian dust (e.g., 1), no spectral evidence for significant deposits of evaportites (e.g., carbonates or sulfates) have been found. Most investigations into Mars aqueous mineralogy have been global in scope with only a few directed studies into localized areas (e.g., 2). We have begun searching for localized deposits of carbonates or sulfates in putative lacustrine basins. We utilize a hydrologic routing model to identify basins with large drainage areas that are shallow because such basins are more likely to accumulate aqueous minerals in high concentration. This model uses MOLA topography to determine drainage and basin patterns and depths of depressions. Evidence for surface water flow activity in these lacustrine basins are then compiled by examination of MOLA shaded relief maps, and available MOC and THEMIS imaging. Shallow basins which contain evidence for surface flow activity (stream features, ancient lakebeds) in the image data are prioritized for spectral analysis. TES emissivity spectra of candidate basins are assembled into a hyperspectral cube that allows visualizing spatial relationships that might be missed if the spectra were examined individually. The Minimum Noise Fraction (MNF) transform algorithum is run on the hyperspectral cube, producing a multiband MNF image. These images allow inter-orbital (i.e., atmospheric) variation to be identified and removed from the scene so that remaining spectral variation is related to surface spectral units. Areas of spatially-continuous MNF values are defined as regions of interest (ROI) and average spectra from each ROI are collected. These mean ROI spectra are examined by linear deconvolution using Acidalia- Syrtis-type, hematite, two atmospheric dust, two water-ice cloud, and surface dust endmembers. Spectra that are not well matched by any combination of the above endmembers are then atmospherically corrected. The atmospherically-corrected spectra are then analyzed by applying both linear deconvolution and the USGS Tetracorder algorithm using the ASU TES spectral library to determine if aqueous minerals are present. We will present TES spectra of lacustrine basins as detected by the basin fill model near Flaugergues crater and discuss their potential to harbor evidence of aqueous mineralogy. [1] Bandfield et al. 2003. Science 301, 1084; [2] Stockstill et al. 2003, Sixth Mars Conf, \#3183.
DE: 3665 Mineral occurrences and deposits
DE: 5410 Composition
DE: 5464 Remote sensing
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting