Véronique Ansan

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Dendritic valleys on the plateau and canyons of the Valles Marineris region were identified from Thermal Emission Imaging System (THEMIS) images taken by Mars Odyssey. The geomorphic characteristics of these valleys, especially their high degree of branching, favor formation by atmospheric precipitation. The presence of inner channels and the maturity of(More)
[1] OMEGA/Mars Express has discovered large outcrops rich in phyllosilicates in the region of Mawrth Vallis, Mars (around 20 W, 25 N). The region is located in Noachian highly cratered terrains, close to the limit of the Martian dichotomy, where the outflow channel Mawrth Vallis cuts the highlands. We have examined this region using OMEGA spectra of the(More)
a Laboratoire de Planétologie et Géodynamique de Nantes, Université de Nantes/CNRS UMR6112, 2 rue de la Houssinière, BP 92208, 44322 Nantes, France b Institut Astrophysique Spatiale, Université Paris-Sud/CNRS, UMR 8617, 91405 Orsay cedex, France c Laboratoire de Sciences de la Terre, ENS Lyon/CNRS/Université Lyon 1, UMR 5570, 69622 Villeurbanne, France d(More)
[1] Recent gullies on Mars are suspected to be the result of liquid‐water‐bearing flows. A formation from wet flows has been challenged by studies invoking granular (dry) flows. Our study focuses on the sinuous shapes observed for some of the recent Martian gullies. Sinuous gullies are found in locations and slopes (of 10°–15°) similar to straight gullies,(More)
[1] Nili Fossae is a region with fresh exposures of old material. OMEGA spectral data have revealed a strong diversity of minerals in the Nili Fossae region, including mafic minerals and phyllosilicates. Phyllosilicates are found to be primarily Fe-rich smectites (a type of clay minerals). These phyllosilicates are observed only on the Noachian crust, in(More)
[1] A closed depression in the Noctis Labyrinthus region of Mars (at 10.4 S, 98.6 W), believed to have formed in the Late Hesperian, holds an inner pit partially filled with several hundred meters of stratified material. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) visible-near infrared reflectance data reveal signatures of numerous hydrated(More)
Introduction: Terby impact crater is located at the northeastern part of Hellas region (75°E – 30°S) on the cratered highlands. Using multi-dataset available on this area, we investigated the geological story of Terby crater. MOLA altimetry [1] shows that Terby impact crater displays an anomalous morphology compared to other impact crater of ~200 km in(More)
Introduction: OMEGA-MeX data has provided a new spatial distribution of localized concentrations of olivine and phyllosilicates on Mars [1,2,3]. The largest and the highest concentration of olivine is in Nili Fossae [1,4]. Olivine was already identified by TES and THEMIS data that suggested olivine rich lava flows in this area of Nili Fossae [4]. Of(More)
Introduction: Outflow channels on Mars are formed by very energetic floods suggesting catastrophic episodes of concentrated water flows [1]. These floods comes from a gigantic release of water such as in terrestrial glacial surge, but their exact origin is debated. Outflow channels of the Xanthe Terra region east of the Tharsis area are all of the Late(More)