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

• Published in: Planetary and Space Science
• Main Authors: Chevrier, V.F., Roy, R., Meslin, P.Y., Le Mouélic, S., Mathé, P.E., Rochette, P., Bonello, G.
• Other Authors: Arkansas Center for Space and Planetary Sciences, University of Arkansas Fayetteville, Orano Canada Inc, Institut de recherche en astrophysique et planétologie (IRAP), 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), 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), Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), 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), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-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), LED’s CHAT - Digital Art for Interior Design and Communication, ANR-16-CE31-0012,MARS-PRIME,Environnement Primitif de Mars(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Antarctica; Ferrar dolerite; Mars; Regolith; Weathering; Reflectance spectroscopy; LIBS; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarctic; Antarc*
• Online Access: https://hal.science/hal-03146661; https://hal.science/hal-03146661/document; https://hal.science/hal-03146661/file/chevrier-pss-2020.pdf; https://doi.org/10.1016/j.pss.2020.105106

International audience 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-mmdeep), 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.