K-Rich Rubbly Bedrock at Glen Torridon, Gale Crater, Mars: Investigating the Possible Presence of Illite

Autor: Agnes Cousin, Matthieu Desjardins, Erwin Dehouck, Olivier Forni, Gael David, Gilles Berger, Gwénaël Caravaca, Pierre-Yves Meslin, Jeremie Lasue, Ollila, Ann M., William Rapin, Patrick Gasda, Sylvestre Maurice, Olivier Gasnault, Wiens, Roger C.
Přispěvatelé: 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), Institut Polytechnique LaSalle Beauvais, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-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), Los Alamos National Laboratory (LANL), Lunar and Planetary Institute, 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 Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Zdroj: HAL
52nd Lunar and Planetary Science Conference
52nd Lunar and Planetary Science Conference, Lunar and Planetary Institute, Mar 2021, The Woodlands, United States
Popis: International audience; Introduction: The Curiosity rover reached the Glen Torridon (GT) area around sol 2300 (January 2019). GT is known to display relatively strong and extensive smectite signatures from orbit [1]. During the last two years of exploring this area, Curiosity has revealed variations in chemical compositions correlated with bedrock facies [2-4]. The spatially dominant type of rock in the lowermost part of GT (which is a lateral continuation of the Jura member) is described as the "rubbly" bedrock because it outcrops as small pieces of bedrock embedded in soil. The rubbly bedrock is composed of finely-laminated mudstones and is characterized by enrichments in K2O and SiO2 [3], whereas the slabs of coherent bedrock adjacent to it are lower in K2O but enriched in MgO [3]. Another mudstone layer with a low MgO/high K2O type of composition is also observed in the overlying Knockfarril Hill member, between Glen Etive and Central Butte. X-ray diffraction (XRD) analyses performed by the CheMin instrument showed that the Jura coherent bedrock contains ~30 wt% of Fe-smectites [5]. However, no XRD analysis was performed on the rubbly bedrock, and the discussion below is thus based solely on elemental compositions measured by ChemCam [6,7]. The objective of this work is to discuss clues regarding the mineralogy of the GT rubbly bedrock: in particular whether the enrichment in K2O is related to partial illitization of the clay minerals, or to a mixing with K-feldspars? Elevated K2O abundances were previously observed in the Kimberley area [8-9], on the floor of Aeolis Palus [10], where CheMin results showed an associated enrichment in K-feldspar (sanidine) [9]. K-feldspars were also observed in igneous rocks such as trachytes [11,12]. In this study, data from the rubbly bedrock of GT are therefore compared to data from Kimberley and from the trachytic igneous rocks observed at Bradbury. Some plagioclase-rich igneous rocks are also used for comparison [12]. Methodology: ChemCam uses the LIBS technique to perform remote chemical analyzes [6,7,12]. The laser beam (300-500 µm, [13]) is large enough that it mostly samples mixtures of mineral phases (as opposed to pure phases), especially in mudstones. Therefore, we used trends in elemental ratios to interpret the mineralogy of the rocks. Compositions with a sum of oxides
Databáze: OpenAIRE
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