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Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars
Mustard, J. F.; Wray, J. J.; Ehlmann, B. L. +2 more
Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic…
A comet-like escape of ionospheric plasma from Mars
Barabash, S.; Lundin, R.; Holmström, M. +4 more
New measurements of the ion escape from Mars display a mantle of low-energy ionospheric ions swept from the dayside over the terminator, expanding into the tail in a comet-like fashion. The finding is based on data obtained with new energy settings for the ASPERA-3 ion mass analyzer (IMA), enabling us to also measure cold ionospheric ions. By incl…
Solar forcing and planetary ion escape from Mars
Fedorov, A.; Barabash, S.; Lundin, R. +4 more
The variability of planetary ion escape from Mars is studied using data from the Ion Mass Analyzer, IMA, on Mars Express (MEX). 42 orbits were selected during 17 months for different solar wind conditions, focusing on the low energy (~30 - 800 eV) heavy ion (e.g. O+, O2 + and CO2 +) outflow. A…
Structure and dynamics of the solar wind/ionosphere interface on Mars: MEX-ASPERA-3 and MEX-MARSIS observations
Barabash, S.; Lundin, R.; Woch, J. +8 more
The measurements of the local plasma parameters of the ionospheric and solar wind plasmas and the magnetic field strength carried out by the ASPERA-3 and MARSIS experiments onboard Mars Express (MEX) in the subsolar region of the induced Martian magnetosphere provide us with a first test of the pressure balance across the solar wind/ionosphere int…
Phyllosilicate and sulfate-hematite deposits within Miyamoto crater in southern Sinus Meridiani, Mars
Clark, R. N.; Arvidson, R. E.; Morris, R. V. +13 more
Orbital topographic, image, and spectral data show that sulfate- and hematite-bearing plains deposits similar to those explored by the MER rover Opportunity unconformably overlie the northeastern portion of the 160 km in diameter Miyamoto crater. Crater floor materials exhumed to the west of the contact exhibit CRISM and OMEGA NIR spectral signatu…
Transient layers in the topside ionosphere of Mars
Gurnett, D. A.; Morgan, D. D.; Kopf, A. J. +1 more
Radar soundings from the MARSIS instrument on board the Mars Express spacecraft have shown that distinct layers can occur in the topside ionosphere of Mars, well above the main photo-ionization layer. These layers appear as cusps, or sometimes steps, in plots of the time delay as a function of frequency. Usually only one topside layer is observed,…
Confirmation and utilization of the ``production function'' size-frequency distributions of Martian impact craters
Neukum, Gerhard; Werner, Stephanie; Hartmann, William K.
On any planetary surface, impacts of interplanetary bodies create an initial (or ``production function'') size-frequency distribution (SFD) of impact craters. Recent questions have been raised about whether this size distribution can be reliably detected, especially at small sizes. In a test area, we confirm an excellent fit to the distribution we…
Spectral variability of the Martian high latitude surfaces
Bibring, J. -P.; Gondet, B.; Langevin, Y. +3 more
We report the surface distributions of some minerals in the high latitude (>50°) regions of Mars using the OMEGA/MEx observations in the near-infrared wavelength domains (1-2.5 µm). Mafic minerals (pyroxene and olivine) are observed in the low albedo terrains. The identification of these minerals is consistent with the presence of volcani…