Search Publications
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…
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 …
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…
Tropical mountain glaciers on Mars: Altitude-dependence of ice accumulation, accumulation conditions, formation times, glacier dynamics, and implications for planetary spin-axis/orbital history
Head, James W.; Forget, Francois; Fastook, James L. +1 more
Fan-shaped deposits up to ∼166,000 km in area are found on the northwest flanks of the huge Tharsis Montes volcanoes in the tropics of Mars. Recent spacecraft data have confirmed earlier hypotheses that these lobate deposits are glacial in origin. Increased knowledge of polar-latitude terrestrial glacial analogs in the Antarctic Dry Valleys has be…
Evolution and depositional environments of the Eberswalde fan delta, Mars
Hauber, Ernst; Pondrelli, Monica; Rossi, Angelo Pio +4 more
The Eberswalde crater and its contributing basins have been analyzed in detail in order to reconstruct the geological evolution of the water-related landforms with particular focus on the Eberswalde delta-like feature. Based on a complex strata organization characterized by a topset-foreset-bottomset geometry, typical of delta progradation on Eart…
Mineralogy of Terra Meridiani and western Arabia Terra from OMEGA/MEx and implications for their formation
Bibring, J. -P.; Arvidson, R. E.; Gondet, B. +5 more
Analyses of Mars Express OMEGA hyperspectral data (0.4-2.7 µm) for Terra Meridiani and western Arabia Terra show that the northern mantled cratered terrains are covered by dust that is spectrally dominated by nanophase ferric oxides. Dark aeolian dunes inside craters and dark streaks extending from the dunes into the intercrater areas in man…
Dust devil speeds, directions of motion and general characteristics observed by the Mars Express High Resolution Stereo Camera
HRSC Co-Investigator Team; Greeley, Ronald; Whelley, Patrick L. +4 more
A total of 205 dust devils were detected in 23 High Resolution Stereo Camera (HRSC) images taken between January 2004 and July 2006 with the ESA Mars Express orbiter, in which average dust devil heights were ∼660 m and average diameters were ∼230 m. For the first time, dust devil velocities were directly measured from orbit, and range from 1 to 59…
Formation and evolution of the chaotic terrains by subsidence and magmatism: Hydraotes Chaos, Mars
Mangold, Nicolas; Neukum, Gerhard; Costard, François +3 more
The origin of the martian chaotic terrains is still uncertain; and a variety of geologic scenarios have been proposed. We provide topographic profiles of different chaos landscapes, notably Aureum and Hydraotes Chaos, showing that an initial shallow ground subsidence occurred at the first step of the chaos formation. We infer that the subsidence w…