HR: 14:55h
AN: P13C-06    [Abstracts]
TI: The distribution of mafic minerals on Mars as inferred by the OMEGA/Mars Express dataset
AU: * Gendrine, A
EM: Aline_Gendrin@brown.edu
AF: Brown University Geological Sciences, Box 1846, Providence, RI 02912
AU: * Gendrine, A
EM: Aline_Gendrin@brown.edu
AF: Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, 91405 France
AU: Bibring, J P
EM: bibring@ias.u-psud.fr
AF: Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, 91405 France
AU: Poulet, F
EM: francois.poulet@ias.u-psud.fr
AF: Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, 91405 France
AU: Mustard, J
EM: John_Mustard@brown.edu
AF: Brown University Geological Sciences, Box 1846, Providence, RI 02912
AU: Kanner, L
EM: Lisa_Kanner@brown.edu
AF: Brown University Geological Sciences, Box 1846, Providence, RI 02912
AU: Gondet, B
EM: Gondet@ias.u-psud.fr
AF: Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, 91405 France
AU: Langevin, Y
EM: Lengevin@ias.u-psud.fr
AF: Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, 91405 France
AB: We use the Modified Gaussian Model (MGM) to model the contributions of olivine, Low Calcium Pyroxene (LCP) and High Calcium Pyroxene (HCP) in OMEGA visible and near-infrared reflectance spectra, with the goal to map the global distributions of olivine and pyroxenes on Mars. The MGM technique allows us to separate to some extent the contributions of these different minerals that are intricately convolved when using techniques based on spectral ratios or parameters. This work extends our previous analyses based on the MGM by analyzing the entire OMEGA wavelength range from the visible through near infrared. This allows us to simultaneously model both the 1 and 2 æm absorption features, providing important constraints on the results. To model the 1 æm feature, we use absorptions bands of LCP and HCP, olivine and a ferric absorption while the 2 æm feature only requires absorptions of LCP and HCP. To facilitate rapid analysis of the large OMEGA data set, we apply constraints on the model absorptions. The maps that we obtain show that high concentrations of HCP are observed in extensive areas on the planet, with regions in Valles Marineris and Syrtis Major showing the strongest signatures. Many areas are correlated to dark sand deposits observed in high-resolution images, sometimes in apparently thin layers. High concentrations of LCP are observed in localized areas associated with Noachian-aged ancient cratered terrains. Three regional concentrations are observed: within and over a large region south-east of Eos Chasma, north of Syrtis Major in Nilosyrtis and Nili Fossae, and north of Terra Meridiani. The olivine map is more tentative. It shows high concentrations in Nili Fossae, Syrtis Major, Terra Meridiani, some areas in Valles Marineris, and crater floors scattered through the highlands.
DE: 5410 Composition (1060, 3672)
DE: 5420 Impact phenomena, cratering (6022, 8136)
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005