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

Abstract

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

Dulovo Crater'i̇n Morfoloji̇si̇ Ve Jeoloji̇si̇ni̇n Araştirilmasi; Southern Libya Montes, Mars

“…We used the CAT (CRISM Analysis Tool Kit) software; the predefined band combinations within the program enhances mineralogical differences of the rocks [23]. The results are comparable with previous studies at Dulovo crater [1, 2] ( Figure 5).…”

Quantitative compositional analysis of martian mafic regions using the MEx/OMEGA reflectance data 1. Methodology, uncertainties and examples of application

“…(B) The abundances of three major minerals correspond to the simulations shown in (A). to bottom, the HCP, LCP and PLG abundances and grain sizes are plotted versus the pyroxene band depth as defined in Poulet et al (2007). The horizontal dashed red lines indicate the input value of each parameter.…”

“…Using classical methods of spectral identification (spectral parameter, Modified Gaussian Model, linear mixing), OMEGA has provided consistent identification and spatial distribution of several classes of mafic minerals (Mustard et al, 2005;Poulet et al, 2007). The Noachian crust is enriched in low-Ca pyroxene, with respect to more recent lavas flows in which high-Ca pyroxene dominates, whereas high relative concentration of olivine is observed in dunes and eroded layers corresponding to ancient lava flows or melt ejectas.…”

The science process for selecting the landing site for the 2011 Mars Science Laboratory

“…A northward traverse would cross the boundary between distinct, diverse units exposing Hesperian and Noachian-aged sequences with hydrated and phyllosilicate mineral signatures (Bibring et al, , 2006Ehlmann et al, 2010;Mustard et al, 2008Mustard et al, , 2010Poulet et al, 2007). Many of the mineral signatures may comprise evidence for past habitable environments (Farmer and Des Marais, 1999).…”

“…With these guidelines in mind, seven new candidate sites were submitted by the science community and discussed by the Steering Committee in December 2009 (Tables 4 and 5, Fig. 3): 1) Nili Fossae carbonate plains (Ehlmann et al, 2008b) including ultramafic, phyllosilicate-bearing, and carbonate-bearing outcrops (21.7 N, 78.8E), 2) a diverse assemblage of minerals straddling the Noachian-Hesperian boundary in northeast Syrtis Major (16.71N,76.91E) with an ellipse to the north of the previous Syrtis sites (e.g., Bibring et al, 2005Bibring et al, , 2006Ehlmann et al, 2010;Mustard et al, 2008Mustard et al, , 2010Poulet et al, 2007), 3) a delta deposit Fig. 4.…”