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10 results on '"Arkansas Center for Space and Planetary Sciences"'

1. Geochemical and spectral characterization of an altered Antarctic dolerite: Implications for recent weathering on Mars

Author

G. Bonello, Pierre-Etienne Mathé, R. Roy, S. Le Mouélic, Pierre Rochette, P.-Y. Meslin, Vincent Chevrier, Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], Orano Canada Inc, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique - Angers (LPG-ANGERS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), LED’s CHAT - Digital Art for Interior Design and Communication, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and ANR-16-CE31-0012,MARS-PRIME,Environnement Primitif de Mars(2016)

Subjects
010504 meteorology & atmospheric sciences, chemistry.chemical_element, Mineralogy, Maghemite, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Astronomy and Astrophysics, Weathering, Pyroxene, Mars Exploration Program, Manganese, engineering.material, 01 natural sciences, Regolith, Spectral line, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, engineering, 010303 astronomy & astrophysics, Dissolution, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present new mineralogical, chemical and spectral analysis of an alteration profile on the Ferrar dolerite (Dry Valley, Antarctica), complementing a previous study (Chevrier et al., 2006a). The whole profile is about 5 ​cm long and subdivided into three different layers: a brown surface rind inferior to 1 ​mm in thickness, followed by a brownish-grey discoloration zone from 1 to 5 ​mm depth and finally a dark fresh core. Mineralogical (X-Ray Diffraction), chemical (EDAX, LIBS), and spectral (FTIR) measurements indicate the formation of iron (oxy)-hydroxides (maghemite) in the very top millimeter of the alteration profile, resulting from the destabilization of ferromagnesian minerals (pyroxene). This zone also exhibits strong hydration features as evidenced by LIBS hydrogen signal and the 2.80 ​μm water band in reflectance spectra. Below this alteration zone (around 5-mm-deep), spectral measurements indicate a discolored zone characterized by an enrichment in pyroxene (1.00 and 2.00 ​μm bands), possibly due to the dissolution of the glass component in the matrix. However, despite these spectral changes, the overall chemistry and mineralogy of the sample remains largely unaffected. This suggests that recent cold and dry weathering on the surface of Mars may spectrally modify surfaces of basaltic rocks, by forming iron (and manganese) (oxy)-hydroxides, but essentially in the very uppermost millimeter and that the underlying mineralogy should remain intact.

Published
2020

2. The Physical Origin of the Venus Low Atmosphere Chemical Gradient

Author

David A. Bonhommeau, Sébastien Lebonnois, Vincent Chevrier, Fernando García-Sánchez, Daniel Cordier, Sara Port, Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Venus, 01 natural sciences, Instability, Astrobiology, Atmosphere of Venus, Atmosphere, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], geography, Molecular diffusion, geography.geographical_feature_category, biology, Astronomy and Astrophysics, biology.organism_classification, Supercritical fluid, Volcano, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

Venus shares many similarities with the Earth, but concomitantly, some of its features are extremely original. This is especially true for its atmosphere, where high pressures and temperatures are found at the ground level. In these conditions, carbon dioxide, the main component of Venus' atmosphere, is a supercritical fluid. The analysis of VeGa-2 probe data has revealed the high instability of the region located in the last few kilometers above the ground level. Recent works have suggested an explanation based on the existence of a vertical gradient of molecular nitrogen abundances, around 5 ppm per meter. Our goal was then to identify which physical processes could lead to the establishment of this intriguing nitrogen gradient, in the deep atmosphere of Venus. Using an appropriate equation of state for the binary mixture CO2-N2 under supercritical conditions, and also molecular dynamics simulations, we have investigated the separation processes of N2 and CO2 in the Venusian context. Our results show that molecular diffusion is strongly inefficient, and potential phase separation is an unlikely mechanism. We have compared the quantity of CO2 required to form the proposed gradient with what could be released by a diffuse degassing from a low volcanic activity. The needed fluxes of CO2 are not so different from what can be measured over some terrestrial volcanic systems, suggesting a similar effect at work on Venus., Published in The Astrophysical Journal

Published
2019

3. Mineralogical record of the redox conditions on early Mars

Author

Nicolas Mangold, A. Gaudin, Vincent Chevrier, Erwin Dehouck, State University of New York (SUNY), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Arkansas Center for Space and Planetary Sciences, and University of Arkansas [Fayetteville]

Subjects
010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Context (language use), Weathering, 01 natural sciences, Mineralogy Mars, Astrobiology, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Martian surface, 0103 physical sciences, Oxidizing agent, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Martian, Atmosphere, Chemistry, Noachian, surface Mars, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science
Abstract

International audience; Sulfates and Fe-oxides identified on the Martian surface by orbital and in situ missions indicate that oxidizing conditions have existed on early Mars, at least locally and/or episodically. In the context of rock alteration and weathering, redox conditions are especially critical for the behavior of iron, which is soluble in its divalent state but insoluble in its trivalent state. Here, we combine results from a series of laboratory experiments conducted under Mars-like conditions to address the influence of highly-oxidizing compounds such as hydrogen peroxide (H2O2) on the alteration pathways of primary materials. We show that, if early Mars had a dense CO2 atmosphere allowing for relatively “warm and wet” conditions and surface weathering, highly-oxidizing conditions would have strongly inhibited the formation of Fe/Mg-smectite clays from alteration of igneous ferromagnesian minerals, and possibly enhanced the formation of carbonates. But a decade of mineral mapping of the Martian surface show abundant, widespread Fe/Mg-clays and rare carbonates, which we interpret here as a mineralogical record of poorly-oxidizing (or even reducing) conditions during most of the Noachian era. Oxidizing conditions would have occurred later in Martian history as a consequence of a higher rate of H2 escape or of a lower rate of volcanic outgassing, or both.

Published
2016

4. Experimental determination of acetylene and ethylene solubility in liquid methane and ethane: Implications to Titan’s surface

Author

Vincent Chevrier, J. Ph. Combe, A. Wagner, S. Singh, Z. McMahon, D. Cordier, IMEC (IMEC), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Arkansas Center for Space and Planetary Sciences, and University of Arkansas [Fayetteville]

Subjects
[PHYS]Physics [physics], Ethylene, 010504 meteorology & atmospheric sciences, Atmospheric models, Chemistry, Inorganic chemistry, Mole fraction, 01 natural sciences, Methane, chemistry.chemical_compound, symbols.namesake, Acetylene, 13. Climate action, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], 0103 physical sciences, symbols, [CHIM]Chemical Sciences, Solubility, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Stratosphere, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

In this study, the solubility of acetylene (or ethyne, C2H2) and ethylene (or ethene, C2H4) in liquid methane (CH4) and ethane (C2H6) has been experimentally determined at Titan surface temperature (90 K) and pressure (1.5 bars). As predicted by theoretical models, the solubilities of acetylene and ethylene are very large at Titan temperature and these species are most likely to be abundantly present in the lakes and as evaporites on the shores or dry lake beds. Our results indicate the solubility of 4.9 × 10−2 mole fraction for acetylene in methane and 48 × 10−2 mole fraction in ethane; for ethylene, 5.6 × 10−1 mole fraction in methane and 4.8 × 10−1 mole fraction in ethane. Assuming the mole fractions from atmospheric models in the lower stratosphere and equilibrium with the surface, we determined that the lakes on Titan that cover ∼400,000 km2 are not saturated. The liquid lakes on Titan act as an important reservoir for both acetylene and ethylene. Assuming difference of methane and ethane content in the lakes at different latitudes, the difference in solubility in liquid methane and ethane, solutes in lakes may change with the temporal evolution (such as; evaporation and condensation) over seasons and geological time scales.

Published
2017

5. Near-infrared spectra of liquid/solid acetylene under Titan relevant conditions and implications for Cassini/VIMS detections

Author

F. C. Wasiak, S. Singh, J. Ph. Combe, S. Le Mouélic, E. Le Menn, T. B. McCord, Vincent Chevrier, Thomas Cornet, L. A. Roe, Canadian Explosives Research Laboratory, CANMET, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], and Bear Fight Institute

Subjects
Materials science, 010504 meteorology & atmospheric sciences, Infrared, Near-infrared spectroscopy, Analytical chemistry, Infrared spectroscopy, Astronomy and Astrophysics, 01 natural sciences, Astrobiology, chemistry.chemical_compound, symbols.namesake, Acetylene, chemistry, 13. Climate action, Space and Planetary Science, Absorption band, [SDU]Sciences of the Universe [physics], 0103 physical sciences, symbols, Spectral resolution, Titan (rocket family), Spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Acetylene is thought to be abundant on Titan according to most photochemical models. While detected in the atmosphere, its likely presence at the surface still lacks physical evidence. It is thought that solid acetylene could be a major component of Titan’s lakes shorelines and dry lakebed, detected as the 5 μm-bright deposits with the Cassini/VIMS instrument. Acetylene could also be present under its liquid form as dissolved solids in Titan’s methane–ethane lakes, as emphasized by thermodynamics studies. This paper is devoted to the near-infrared spectroscopy study of acetylene under solid and liquid phases between 1 and 2.2 μm, synthesized in a Titan simulation chamber that is able to reproduce extreme temperature conditions. From experiments, we observed a ∼10% albedo increase between liquid acetylene at 193–188 K and solid acetylene at 93 K. Using the NIR spectroscopy technique we successfully calculated the reflectivity ratio of solid/liquid acetylene as 1.13. The second difference we observed between liquid and solid acetylene is a shift in the major absorption band detected at 1.54 μm, the shift of ∼0.01 μm occurring toward higher wavelength. In order to assess the detectability of acetylene on Titan using the Cassini/VIMS instrument, we adapted our spectra to the VIMS spectral resolution. The spectral band at 1.55 μm and a negative slope at 2.0 μm falls in the Cassini/VIMS atmospheric windows over several VIMS infrared spectels, thus Cassini/VIMS should be able to detect acetylene.

Published
2016

6. CO 2 Sublimation and Mass Wasting on Mars

Author

Sylvest, Matthew E., Conway, Susan J., Patel, Manish R., Dixon, John C., Barnes, Adam, Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), The Open University [Milton Keynes] (OU), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), and Center for Advanced Spatial Technologies (CAST)

Subjects
Martian, geography, Empirical data, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Landform, Mars Exploration Program, Mass wasting, 01 natural sciences, Regolith, Astrobiology, Geophysics, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, General Earth and Planetary Sciences, Sublimation (phase transition), 010303 astronomy & astrophysics, Sediment transport, Geology, 0105 earth and related environmental sciences
Abstract

Sublimation is a recognized process by which planetary landscapes can be modified. However, interpretation of whether sublimation is involved in downslope movements on Mars and other bodies is restricted by a lack of empirical data to constrain this mechanism of sediment transport and its influence on landform morphology. Here we present the first set of laboratory experiments under Martian atmospheric conditions which demonstrate that the sublimation of CO2 ice from within the sediment body can trigger failure of unconsolidated, regolith slopes and can measurably alter the landscape. Previous theoretical studies required CO2 slab ice for movements, but we find that only frost is required. Hence, sediment transport by CO2 sublimation could be more widely applicable (in space and time) on Mars than previously thought. This supports recent work suggesting CO2 sublimation could be responsible for recent modification in Martian gullies.

Published
2016

7. Experimental constraints on the composition and dynamics of Titan's polar lakes

Author

F. C. Wasiak, D. Cordier, Vincent Chevrier, Edgard G. Rivera-Valentin, Adrienn Luspay-Kuti, A. Wagner, S. Singh, Southwest Research Institute [San Antonio] (SwRI), Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), IMEC (IMEC), and Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)

Subjects
Mass flux, 010504 meteorology & atmospheric sciences, Thermodynamic equilibrium, Thermodynamics, 01 natural sciences, Methane, chemistry.chemical_compound, symbols.namesake, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Dissolution, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Hydrology, chemistry.chemical_classification, [PHYS]Physics [physics], Geophysics, Hydrocarbon, chemistry, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], symbols, Polar, Titan (rocket family), Ternary operation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract

Titan's polar lakes are thought to be predominantly composed of liquid ethane and methane; however, little is known on the ratio of these hydrocarbons in the lakes, and the stability and dynamics of these mixtures. Here we provide the first experimental constraints under Titan surface conditions of liquid hydrocarbon mixture evaporation. Our results are relevant to Titan's polar temperatures and pressures (∼92 K and 1.5 bar), and cover a wide range of methane–ethane compositions. We show that evaporation is negligible for pure ethane, but increases nearly linearly with increasing methane concentration. Early dissolution of N2 results in ternary mixtures evaporating, which is modeled by a ‘hybrid’ thermodynamic equilibrium approach combining Perturbed-Chain Statistical Associating Fluid Theory with a diffusion and buoyancy-driven mass flux model. The approach follows the experimental evaporation rate measurements presented in this study, and allows for the calculation of the corresponding liquid methane–ethane–nitrogen ratios. Such results along with Cassini inferred lake evaporation rates can be used to estimate the composition of Titan's polar liquids, and may have implications on their origin. Our results suggest that Ontario Lacus is predominantly composed of ethane (>50–80 mol%), indicating it may be a residual lake following extensive seasonal methane evaporation, and/or might be in contact with a subsurface liquid reservoir.

Published
2015

8. Volatile trapping in Martian clathrates

Author

Frédéric Schmidt, Jérémie Lasue, Eric Chassefière, Megan E. Elwood Madden, Jonathan I. Lunine, Franck Montmessin, Olivier Mousis, Sylvain Picaud, Vincent Chevrier, Azzedine Lakhlifi, Timothy D. Swindle, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), W.M. Keck Laboratory for Space and Planetary Simulation [Fayetteville], Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville]-University of Arkansas [Fayetteville], School of Geology and Geophysics, University of Oklahoma, University of Oklahoma (OU), Center for Radiophysics and Space Research [Ithaca] (CRSR), Cornell University [New York], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Clathrate hydrate, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, Mars, Context (language use), 01 natural sciences, Astrobiology, Atmosphere, Xenon, Clathrates, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Carbon dioxide clathrate, Martian, Atmospheric methane, Astronomy and Astrophysics, Mars Exploration Program, chemistry, 13. Climate action, Space and Planetary Science, Polar caps, Cryosphere
Abstract

International audience; Thermodynamic conditions suggest that clathrates might exist on Mars. Despite observations which show that the dominant condensed phases on the surface of Mars are solid carbon dioxide and water ice, clathrates have been repeatedly proposed to play an important role in the distribution and total inventory of the planet's volatiles. Here we review the potential consequences of the presence of clathrates on Mars. We investigate how clathrates could be a potential source for the claimed existence of atmospheric methane. In this context, plausible clathrate formation processes, either in the close subsurface or at the base of the cryosphere, are reviewed. Mechanisms that would allow for methane release into the atmosphere from an existing clathrate layer are addressed as well. We also discuss the proposed relationship between clathrate formation/dissociation cycles and how potential seasonal variations influence the atmospheric abundances of argon, krypton and xenon. Moreover, we examine several Martian geomorphologic features that could have been generated by the dissociation of extended subsurface clathrate layers. Finally we investigate the future in situ measurements, as well as the theoretical and experimental improvements that will be needed to better understand the influence of clathrates on the evolution of Mars and its atmosphere.

Published
2013

9. Geochemical consequences of widespread clay mineral formation in Mars' ancient crust

Author

Bethany L. Ehlmann, Gilles Berger, Nicolas Mangold, Joseph R. Michalski, David C. Catling, Steven W. Ruff, Eric Chassefière, Paul B. Niles, Vincent Chevrier, Francois Poulet, CRINON, Evelyne, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Mineralogy, Natural History Museum [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astromaterials Research and Exploration Science (ARES), NASA Johnson Space Center (JSC), NASA-NASA, W.M. Keck Laboratory for Space and Planetary Simulation [Fayetteville], Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville]-University of Arkansas [Fayetteville], Institut d'astrophysique spatiale (IAS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Sud - Paris 11 (UP11)

Subjects
010504 meteorology & atmospheric sciences, 0103 physical sciences, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Abstract

International audience; Clays form on Earth by near-surface weathering, precipitation in water bodies within basins, hydrothermal alteration (volcanic- or impact-induced), diagenesis, metamorphism, and magmatic precipitation. Diverse clay minerals have been detected from orbital investigation of terrains on Mars and are globally distributed, indicating geographically widespread aqueous alteration. Clay assemblages within deep stratigraphic units in the Martian crust include Fe/Mg smectites, chlorites and higher temperature hydrated silicates. Sedimentary clay mineral assemblages include Fe/Mg smectites, kaolinite, and sulfate, carbonate, and chloride salts. Stratigraphic sequences with multiple clay-bearing units have an upper unit with Al-clays and a lower unit with Fe/Mg-clays. The typical restriction of clay minerals to the oldest, Noachian terrains indicates a distinctive set of processes involving water-rock interaction that was prevalent early in Mars history and may have profoundly influenced the evolution of Martian geochemical systems. Current analyses of orbital data have led to the proposition of multiple clay-formation mechanisms, varying in space and time in their relative importance. These include near-surface weathering, formation in ice-dominated near-surface groundwaters, and formation by subsurface hydrothermal fluids. Near-surface, open system formation of clays would lead to fractionation of Mars' crustal reservoir into an altered crustal reservoir and a sedimentary reservoir, potentially involving changes in the composition of Mars' atmosphere. In contrast, formation of clays in the subsurface by either aqueous alteration or magmatic cooling would result in comparatively little geochemical fractionation or interaction of Mars' atmospheric, crustal, and magmatic reservoirs, with the exception of long-term sequestration of water. Formation of clays within ice would have geochemical consequences intermediate between these endmembers. We outline the future analyses of orbital data, in situ measurements acquired within clay-bearing terrains, and analyses of Mars samples that are needed to more fully elucidate the mechanisms of martian clay formation and to determine the consequences for the geochemical evolution of the planet.

Published
2013

10. ACETYLENE ON TITAN’S SURFACE

Author

L. Maltagliati, Roger N. Clark, Vincent Chevrier, Thomas Cornet, Sebastien Rodriguez, S. Le Mouélic, J. P. Combe, T. B. McCord, S. Singh, Canadian Explosives Research Laboratory, CANMET, Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), W.M. Keck Laboratory for Space and Planetary Simulation [Fayetteville], Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville]-University of Arkansas [Fayetteville], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, Photochemistry, 01 natural sciences, Methane, chemistry.chemical_compound, symbols.namesake, Acetylene, chemistry, [SDU]Sciences of the Universe [physics], Space and Planetary Science, 0103 physical sciences, symbols, Atmosphere of Titan, Titan (rocket family), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2016

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