Martian surface mineralogy from Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité on board the Mars Express spacecraft (OMEGA/MEx): Global mineral maps

摘要: [1] After 2 years of operation the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite (OMEGA) imaging spectrometer on board Mars Express has acquired data coverage Martian surface with spatial resolution varying between 300 m and 4.8 km, depending pericenter altitude spacecraft's elliptical orbit. We report global distributions some minerals using OMEGA observations in visible near infrared (VNIR) wavelength domains (0.35–2.5 μm). Global maps ferric phases, mafic (pyroxenes olivines), hydrated have been derived from spectral parameters. The limits detection terms abundance for different grain size are given. distribution pyroxenes is general agreement mineral previous telescopic space observations. Fe3+ absorption feature region present everywhere surface. spectra bright regions compare anhydrous nanophase oxides. Terrains water-bearing cover a very small fraction Olivine (Mg-rich compositions) detected more extensive pyroxene-rich zones than previously reported. higher iron content and/or larger (>100 μm) only isolated areas. mineralogy northern low-albedo discussed light these maps. Chemical alteration or oxidation during extrusion producing coating varnish phases over dark basaltic best accounts VNIR properties regions, although glassy composition resulting impact also considered.