Search Publications
Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument
Bibring, J. -P.; Arvidson, R. E.; Langevin, Y. +33 more
Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitié) instrument, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains…
The timing of martian valley network activity: Constraints from buffered crater counting
Head, James W.; Fassett, Caleb I.
Valley networks, concentrations of dendritic channels that often suggest widespread pluvial and fluvial activity, have been cited as indicators that the climate of Mars differed significantly in the past from the present hyperarid cold desert conditions. Some researchers suggest that the change in climate was abrupt, while others favor a much more…
Valley network-fed, open-basin lakes on Mars: Distribution and implications for Noachian surface and subsurface hydrology
Head, James W.; Fassett, Caleb I.
A new catalog of 210 open-basin lakes (lakes with outlet valleys) fed by valley networks shows that they are widely distributed in the Noachian uplands of Mars. In order for an outlet valley to form, water must have ponded in the basin to at least the level of the outlet. We use this relationship and the present topography to directly estimate the…
An overview of radar soundings of the martian ionosphere from the Mars Express spacecraft
Gurnett, D. A.; Persoon, A. M.; Averkamp, T. F. +10 more
The Mars Express spacecraft carries a low-frequency radar called MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) that is designed to study the subsurface and ionosphere of Mars. In this paper, we give an overview of the ionospheric sounding results after approximately one year of operation in orbit around Mars. Several types of…
North polar region of Mars: Advances in stratigraphy, structure, and erosional modification
Herkenhoff, Kenneth E.; Tanaka, Kenneth L.; Skinner, James A. +5 more
We have remapped the geology of the north polar plateau on Mars, Planum Boreum, and the surrounding plains of Vastitas Borealis using altimetry and image data along with thematic maps resulting from observations made by the Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter spacecraft. New and revised geographic and …
Variation of the Martian ionospheric electron density from Mars Express radar soundings
Gurnett, D. A.; Morgan, D. D.; Plaut, J. J. +3 more
The Mars Advanced Radar for Subsurface and Ionospheric Sounding aboard Mars Express has been in operation for over 2 years. Between 14 August 2005 and 31 July 2007, we obtain 34,492 ionospheric traces, of which 14,060 yield electron density profiles and 12,291 yield acceptable fits to the Chapman ionospheric model. These results are used to study …
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…
Spectral and geological study of the sulfate-rich region of West Candor Chasma, Mars
Gendrin, Aline; Mangold, Nicolas; Bibring, Jean-Pierre +7 more
Sulfates have been discovered by the OMEGA spectrometer in different locations of the planet Mars. They are strongly correlated to light toned layered deposits in the equatorial regions. West Candor Chasma is the canyon with the thickest stack of layers and one with the largest area covered by sulfates. A detailed study coupling mineralogy derived…
Observation of the hydrogen corona with SPICAM on Mars Express
Leblanc, F.; Bertaux, J. L.; Quémerais, E. +1 more
A series of seven dedicated Lyman- α observations of exospheric atomic hydrogen in the martian corona were performed in March 2005 with the ultraviolet spectrometer SPICAM on board Mars Express. Two types of observations are analyzed, observations at high illumination (for a solar zenith angle SZA equal to 30°) and observations at low illumination…
Abundance of minerals in the phyllosilicate-rich units on Mars
Mangold, N.; Bibring, J. -P.; Gondet, B. +4 more
Context: Phyllosilicates were definitely identified on Mars by the OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) instrument onboard the Mars Express spacecraft. The identification, characterization, and mapping of deposits of these minerals hold clues to the potential past habitability. They also constitute a key elemen…