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1. Narrow Loophole for H2-Dominated Atmospheres on Habitable Rocky Planets around M Dwarfs

Author

Renyu Hu, Fabrice Gaillard, and Edwin S. Kite

Subjects
Exoplanet atmospheres, Exoplanet surfaces, Extrasolar rocky planets, Exoplanet evolution, Super Earths, Transmission spectroscopy, Astrophysics, QB460-466
Abstract

Habitable rocky planets around M dwarfs that have H _2 -dominated atmospheres, if they exist, would permit characterizing habitable exoplanets with detailed spectroscopy using JWST, owing to their extended atmospheres and small stars. However, the H _2 -dominated atmospheres that are consistent with habitable conditions cannot be too massive, and a moderate-sized H _2 -dominated atmosphere will lose mass to irradiation-driven atmospheric escape on rocky planets around M dwarfs. We evaluate volcanic outgassing and serpentinization as two potential ways to supply H _2 and form a steady-state H _2 -dominated atmosphere. For rocky planets of 1–7 M _⊕ and early-, mid-, and late M-type dwarfs, the expected volcanic outgassing rates from a reduced mantle fall short of the escape rates by > ∼ 1 order of magnitude, and a generous upper limit of the serpentinization rate is still less than the escape rate by a factor of a few. Special mechanisms that may sustain the steady-state H _2 -dominated atmosphere include direct interaction between liquid water and mantle, heat-pipe volcanism from a reduced mantle, and hydrodynamic escape slowed down by efficient upper-atmospheric cooling. It is thus unlikely to find moderate-size, H _2 -dominated atmospheres on rocky planets of M dwarfs that would support habitable environments.

Published
2023
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2. Melting conditions in the modern Tibetan crust since the Miocene

Author

Jinyu Chen, Fabrice Gaillard, Arnaud Villaros, Xiaosong Yang, Mickael Laumonier, Laurent Jolivet, Martyn Unsworth, Leïla Hashim, Bruno Scaillet, and Guillaume Richard

Subjects
Science
Abstract

Crustal melting may play a fundamental role in orogenic processes, but quantifying crustal melt remains difficult. Here, the authors combine pressure-temperature paths, electrical conductivity and geophysical data to elucidate the melting conditions in Tibet since the Miocene.

Published
2018
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3. Publisher Correction: Melting conditions in the modern Tibetan crust since the Miocene

Author

Jinyu Chen, Fabrice Gaillard, Arnaud Villaros, Xiaosong Yang, Mickael Laumonier, Laurent Jolivet, Martyn Unsworth, Leїla Hashim, Bruno Scaillet, and Guillaume Richard

Subjects
Science
Abstract

The original PDF version of this Article contained an error in which Fig. 3 and its legend were omitted and Equations 5 and 6 contained errors.This has been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.

Published
2018
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6. A window in the course of alkaline magma differentiation conducive to immiscible REE-rich carbonatites

Author

Giada Iacono-Marziano, Malcolm Massuyeau, Emmanuel Le Trong, Ida Di Carlo, Johann Tuduri, Fabrice Gaillard, Laurent Bailly, Jérémie Melleton, Grégory Rogerie, Zineb Nabyl, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), University of Johannesburg [South Africa] (UJ), Institut für Mineralogie, Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), University of Johannesburg (UJ), and Westfälische Wilhelms-Universität Münster (WWU)

Subjects
Nephelinite, 010504 meteorology & atmospheric sciences, Geochemistry, 010502 geochemistry & geophysics, 01 natural sciences, Silicate, Cape verde, chemistry.chemical_compound, Igneous rock, chemistry, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Geochemistry and Petrology, Magma, Carbonatite, Carbonate, Igneous differentiation, 0105 earth and related environmental sciences
Abstract

International audience; Rare earth element (REE) enrichments in carbonatites are often described as resulting from late magmatic-hydrothermal or supergene processes. However, magmatic pre-enrichment linked to the igneous processes at the origin of carbonatites are likely to contribute to the REE fertilisation. Experimental constraints reveals that immiscibility processes between carbonate and silicate melts can lead to both REE enrichments and depletions in carbonatites making the magmatic processes controlling REE enrichments unclear.We link REE contents of carbonatites to the magmatic stage at which carbonatites are separated from silicate magma in their course of differentiation. We present results of experiments made at pressure and temperature conditions of alkaline magmas and associated carbonatites differentiation (0.2 to 1.5 GPa; 725 to 975 °C; FMQ to FMQ +2.5), simultaneously addressing crystal fractionation of alkaline magmas and immiscibility between carbonate (calcio-carbonate type) and silicate melts (nephelinite to phonolite type). The experimental data shows that the degree of differentiation, controlling the chemical composition of alkaline melts, is a key factor ruling the REE concentration of the coexisting immiscible carbonate melts. In order to predict carbonate melt REE enrichments during alkaline magma differentiation, we performed a parameterisation of experimental data on immiscible silicate and carbonate melts, based exclusively on the silica content, the alumina saturation index and the alkali/alkaline-earth elements ratio of silicate melts. This parameterisation is applied to more than 1600 geochemical data of silicate magmas from various alkaline provinces (East African Rift, Canary and Cape Verde Islands) and show that REE concentrations of their potential coeval carbonatite melts can reach concentration ranges similar to those of highly REE enriched carbonatites (∑REE > 30 000 ppm) by immiscibility with phonolitic/phono-trachytic melt compositions, while more primitive alkaline magmas can only be immiscible with carbonatites that are not significantly enriched in REE.

Published
2020
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7. A speciation model linking the fate of carbon and hydrogen during coremagma ocean equilibration

Author

Mohamed Ali Bouhifd, Grégory Rogerie, Valérie Malavergne, Fabrice Gaillard, Magma - UMR7327, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géomatériaux et Environnement (LGE ), Université Gustave Eiffel, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), and ANR-18-CE31-0021,GASTON,Les constituants volatils dans les processus magmatiques du noyau aux atmosphères(2018)

Subjects
0303 health sciences, 010504 meteorology & atmospheric sciences, Hydrogen, Lead (sea ice), chemistry.chemical_element, 01 natural sciences, Mantle (geology), Silicate, 03 medical and health sciences, chemistry.chemical_compound, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Magma, Earth and Planetary Sciences (miscellaneous), Lithophile, Saturation (chemistry), Petrology, Carbon, Geology, 030304 developmental biology, 0105 earth and related environmental sciences
Abstract

International audience; The core – mantle differentiation in the magma ocean constitutes a major planetary event that involved two elements that are essential to life: carbon (C) and hydrogen (H). These two elements are conventionally classified as volatiles (ie. atmophile), but they can also evolve into being siderophile and lithophile at the extreme conditions found in planetary magma oceans. We report here a model for H and C species dissolved in silicate melts in equilibrium with iron-rich alloys under variable pressure, temperature and redox conditions. This speciation model is able to reconcile and reproduce a large body of experimental data on metal-silicate partitioning for H and C at carbon-saturation and in C-undersaturated systems. At low pressure, we conclude that the prevailing species in a silicate magma ocean are CO2, CO, H2O, H2, whereas CH4 appears to dominate at high pressure. These speciation changes explain recent experimental observations that (i) C evolves from being strongly siderophile at low pressure to moderately siderophile at high pressure, and (ii) H is not siderophile at low pressure but becomes increasingly so as pressure rises. Moreover, it shows that H becomes increasingly siderophile as the total H content of the silicate melt and C-activity are lowered. Despite it offers a promising reconciliation of a large set of experimental and molecular dynamics observations, this model still suffers from large uncertainties when extrapolated to high pressure. In particular, endmember and mixing properties in both the silicate melt and the molten metal must be independently deciphered.The enhanced CH4 stability in the silicate melt at high pressure couples the fate of C and H in deep magma oceans. In such cases, the solubility of C in the basal ocean depends on the H-content and is higher than C-solubility at low pressure. This implies an increase in C activity as the ascending convective cells of the magma ocean, which may cause C saturation as graphite or diamond unless Fe-metal droplets, having a great C-solubility, are present in the shallow magma ocean. Under certain conditions, enhanced siderophile behaviour for H can lead via a runaway process to the desiccation of the magma ocean.

Published
2022
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8. Ressources en terres rares de l’Europe et du Groenland : potentiel minier et enjeux

Author

Nicolas CHARLES, Johann TUDURI, Gaétan LEFEBVRE, Olivier POURRET, Fabrice GAILLARD, Kathryn GOODENOUGH, CHARLES, Nicolas, Production durable et technologies de l'environnement - Analyse Systémique des TErres Rares – flux et stocks - - ASTER2011 - ANR-11-ECOT-0002 - ECOTECH - VALID, Sophie Decrée, and Philippe Boulvais, PhD

Subjects
[CHIM.INOR] Chemical Sciences/Inorganic chemistry, [QFIN.GN] Quantitative Finance [q-fin]/General Finance [q-fin.GN], Greenland, [SDU.STU.PE] Sciences of the Universe [physics]/Earth Sciences/Petrography, Groenland, Europe, ressources, [SDU.STU.AG] Sciences of the Universe [physics]/Earth Sciences/Applied geology, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDE.ES] Environmental Sciences/Environmental and Society, resources, Terres rares TR, Rare earth elements, ComputingMilieux_MISCELLANEOUS, [SDU.STU.MI] Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

Les Eléments de Terres Rares sont distribués à faibles teneurs dans grand nombre de roches. Pour en augmenter les concentrations et en faire une ressource exploitable, de multiples processus géologiques sont à l’œuvre. Charles et al. font l’inventaire exhaustif des domaines européens où des concentrations intéressantes en Eléments de Terres Rares sont reconnues.

Published
2022

10. Redox Controls during Magma Ocean Degassing

Author

Fabien Bernadou, Mathieu Roskosz, Yves Marrocchi, Giada Iacono-Marziano, Mohamed Ali Bouhifd, Bruno Scaillet, Manuel A. Moreira, Grégory Rogerie, Fabrice Gaillard, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE31-0021,GASTON,Les constituants volatils dans les processus magmatiques du noyau aux atmosphères(2018), and ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010)

Subjects
010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Astrobiology, Atmosphere, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Geochemistry and Petrology, Lithosphere, Earth and Planetary Sciences (miscellaneous), Volatiles, 0105 earth and related environmental sciences, Crust, magma ocean, Outgassing, Geophysics, volatiles, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], redox, Magma, atmosphere, Terrestrial planet, Geology, mantle
Abstract

International audience; Nitrogen, carbon, hydrogen and sulfur are essential elements for life and comprise about 1 % of terrestrial planet masses. These elements dominate planetary surfaces due to their volatile nature, but the Earth's interior also constitutes a major C-H-N-S reservoir. Resolving the origin of the surficial versus deep volatile reservoirs requires the past 4.5 Giga-years of mantle outgassing and ingassing processes to be reconstructed, involving many unknowns. As an alternative, we propose to define the primordial distribution of volatiles resulting from degassing of the Earth's magma ocean (MO). The equilibrium partitioning of C-H-ON -S elements between the MO and its atmosphere is calculated by means of solubility laws, extrapolated to high temperatures and over a large range of redox conditions. Depending on the redox conditions, the amount of volatiles, and the size of the MO considered, we show that the last MO episode may have degassed 40-220 bar atmospheres, whereas hundreds to thousands of ppm of C-H-ON -S can be retained in the magma. Two contrasting scenarios are investigated: reduced vs. oxidized MO. For reduced cases (IW+2) would be dry and C-N-S-rich. An intermediate redox state produces a C-N atmosphere. In many cases, the present-day surficial abundances (atmosphere+ocean+crust) of C and N, the most volatile elements, are very close to the calculated primordial MO-atmosphere distribution. This probably means that lithospheric recycling and post-magma ocean degassing only moderately alter the surficial abundances of these elements. Sulfur, in contrast, must have been mostly outgassed by post-MO events. Changes in redox conditions during magma ocean degassing played a first order role in the composition of the primordial atmosphere of planets. We suggest that the more oxidized conditions on Venus due to H-loss may have played a role in the growth of a dry MO atmosphere on this planet compared to an H-bearing one on Earth. To verify these first order assertions, constraints on volatile behaviour under extreme magma ocean conditions and upon magma ocean solidification are urgently needed.

Published
2022
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12. The role of assimilation and volatiles in the formation and metal enrichment of magmatic sulfide ores: constraints from experimental petrology and application to the Noril’sk-Talnakh ore deposits (Russia)

Author

Giada Iacono-Marziano, Nicholas Arndt, Margaux Le Vaillant, Fabrice Gaillard, Steve J. Barnes, Laurent Arbaret, Belinda Godel, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Métallogénie - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), CSIRO Mineral Ressources Kensington, Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), and Iacono Marziano, Giada

Subjects
chemistry.chemical_classification, Sulfide, Terrigenous sediment, Volcanogenic massive sulfide ore deposit, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, [SDU.STU.PE] Sciences of the Universe [physics]/Earth Sciences/Petrography, chemistry.chemical_element, Sulfur, [SDU] Sciences of the Universe [physics], chemistry.chemical_compound, chemistry, [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Magma, Sedimentary rock, Sulfate, Mafic, Petrology
Abstract

International audience; Most of the intrusions in the Noril’sk-Talnakh region (Siberia) are hosted in thick sedimentary sequences including abundant evaporitic and terrigenous sedimentary rocks. Three mafic-ultramafic intrusions in this region contain unusually thick massive sulfide deposits that constitute one of the world’s largest economic concentrations of Ni, Cu and PGE. The interaction of Siberian magmas with sulfate and organic matter-rich sedimentary rocks has been proposed as a mechanism for the origin of these remarkable sulfide deposits. Here we fully investigate the interaction and reaction paths, by means of experiments at magmatic conditions and by thermodynamic modeling. We demonstrate how the assimilation of sulfate and organic matter in mafic-ultramafic magmas affects magma composition, crystallization and sulfide saturation. We identify the conditions that favored assimilation and ore formation in Noril’sk-Talnakh intrusions and conclude that the assimilation of sulfate-rich rocks enriched Siberian magmas in sulfur, while the carbonaceous rocks ensured the reduction of the oxidized sulfur and the segregation of exceptional amounts of sulfide melt.One of the consequences of the assimilation of organic material is the formation of an abundant fluid phase in the mafic magma. Our experimental work shows that the strong association between sulfide melt and fluid phase may have a major control on both the mobility and the metal enrichment of the sulfide melt. The fluid phase seems to play a critical role on the accumulation of the sulfide liquid by facilitating the coalescence of those sulfide droplets that are attached to gas bubbles. The experiments also reveal that the presence of a fluid phase consumes the sulfide melt concentrating metals in it. This process may have occurred during the formation of Norilsk-Talnakh sulfide ores and could explain the decreasing sulfide content and increasing metal content from the bottom to the top of the intrusions, i.e. from S-rich, PGE-poor massive sulfides at the base, to disseminated sulfides at intermediate levels and to S-poor, PGE-rich ores in the upper part.

Published
2021

13. Partial melting as an efficient mechanism to produce rare metal granite?

Author

Fabrice Gaillard, Jérémie Melleton, Eric Gloaguen, Saskia Erdmann, Josselyn Garde, Alexis Plunder, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Métallogénie - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Magma - UMR7327

Subjects
Metal, Materials science, Chemical engineering, [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 13. Climate action, visual_art, Partial melting, visual_art.visual_art_medium, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 15. Life on land, ComputingMilieux_MISCELLANEOUS, Mechanism (sociology)
Abstract

Rare metal (HFSE such Sn, W, Ta, Nb and LILLE such Li, Rb) granite represent the most enriched magmatic rocks on Earth. This is especially true for some elements that belongs either to the European list of critical raw materials and/or the conflict minerals (eg. Li, Sn, W, Nb, Ta). Rare metal granites generally emplace in the vincinity of S-type granites during late orogenic stages. The fraction crystallisation mechanism is postulated to be the unique way to produce enriched silicate melt that later leads to ore deposits due to a combination of magmatic/hydrothermal processes. However, some problems persist in the explanation of the genesis of rare metal granite: crystal fractionation alone does not lead to the very high rare metal concentrations; field discrepancies exist between rare metal granites and their supposed parent peraluminous granites that in some cases are unknown. An alternative model - based on the integration of geochemical, experimental, paleogeographical and structural studies – suggests that low degree partial melting could be an efficient mechanism to produce critical metals enriched silicate melts enriched. To test whether this hypothesis makes sense, we present a study of the behaviour of W, Sn, Nb and Ta in metamorphic minerals from various metapelitic rocks. The selected samples do not present anomalous bulk concentrations of these elements with respect to an average continental crust. They formed at different pressure temperature conditions, in different orogenic belts. The rock collection comprises (i) amphibolite-facies staurolite bearing rocks, (ii) sillimanite-bearing rocks and (iii) granulite-facies orthopyroxene-bearing rocks. These samples represent the three main stages of the classical evolution of a collisional gradient leading to partial melting: they respectively belong to the muscovite + biotite domain, the muscovite-out reaction and the biotite-out reaction. We first estimate pressure-temperature conditions of formation of the rocks using pseudosection modelling. We then expose a set of LA-ICP-MS data to identify the critical metal carriers minerals in our samples. Meanwhile, we investigate the behaviour of W, Sn, Nb and Ta during the muscovite out reaction with two piston cylinder experiments (a partial melting experiment and a crystallization experiment). The protolith consists of a staurolite-bearing metapelite that did not suffer partial melting. In the light of these new data, we discuss the framework of the production of critical metal enriched silicate melts. We show that the main carrier of W is muscovite (up to 30 ppm) and that biotite handle Sn at high temperature (up to 40ppm). Using both the data from the natural sample and the experiments, we highlight that muscovite releases W during its destabilisation ant that Sn enters in biotite until the mineral breaks. We finally discuss the implication of multiple low degree partial melting / melt extraction as efficient way to produce enriched silicate melts.

Published
2021
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14. Crystallisation sequence of a REE-rich carbonate melt: an experimental approach

Author

Valentin Mollé, Fabrice Gaillard, Zineb Nabyl, Johann Tuduri, Ida Di Carlo, and Saskia Erdmann

Subjects
General Earth and Planetary Sciences, General Environmental Science
Abstract

Carbonatites host the main REE deposits in the world, with bastnaesite being the main REE-bearing mineral of interest. However, the nature of the enrichment process, magmatic vs hydrothermal, is still debated. This study aims to experimentally determine the behaviour of REE elements during carbonatite crystallisation, and if bastnaesite can be directly crystallised from a carbonate melt. Crystallisation experiments have been done from 900 to 600°C at 1 kbar on a REE-rich calciocarbonatitic composition. Calcite (Ca,REE)CO3 is the dominant magmatic mineral, so the residual melt evolves toward natrocarbonatitic compositions as crystallisation proceeds. A small amount of britholite (REE,Ca)5((Si,P)O4)3(OH,F) is observed at high temperatures and is replaced by phlogopite KMg3(AlSi3O10)(OH)2 and apatite (Ca,REE)5(PO4)3(F,OH) at T < 650°C. A small amount of pyrochlore (Ca,Na,REE)2Nb2O6(OH,F) is observed at T < 700°C. No bastnaesite has been found in any crystallisation experiment. We thus performed a bastnaesite saturation experiment at 600°C. The melt saturated with bastnaesite however contains 20 wt% of REE: such high value implies that magmatic saturation of bastnaesite is unlikely to happen in nature. F, Cl and water decrease the temperature of calcite saturation, allowing the system to crystallise at lower temperatures. REE are slightly incompatible with calcite, especially at low temperatures. The residual carbonate melt is thus enriched as crystallisation proceeds. Finally, we collected textural and chemical evidence suggesting the presence of a Na,Cl,REE-rich fluid at high temperatures and under hydrous conditions. Such Na,Cl,REE-rich fluids may play a critical role in the remobilisation of REE and the bastnaesite crystallisation during subsolidus reactions.

Published
2021
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17. Is there a global carbonate layer in the oceanic mantle?

Author

Wilson A. Crichton, Tahar Hammouda, Julien Chantel, Jérémy Guignard, Philippe Goncalves, Geeth Manthilake, Fabrice Gaillard, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Case Western Reserve University [Cleveland], European Synchrotron Radiation Facility (ESRF), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
010504 meteorology & atmospheric sciences, Mantle wedge, Subduction, chemistry.chemical_element, 010502 geochemistry & geophysics, 01 natural sciences, Isothermal process, Mantle (geology), Plate tectonics, chemistry.chemical_compound, Geophysics, chemistry, 13. Climate action, Lithosphere, [SDU]Sciences of the Universe [physics], General Earth and Planetary Sciences, Carbonate, Grain boundary, Compression (geology), Petrology, Carbon, Geology, 0105 earth and related environmental sciences
Abstract

co-auteur étranger; International audience; Previous modeling of carbonate subduction by high‐pressure experimentation has allowed to propose scenarios for bulk carbon return to the mantle, but the detailed transfer mechanisms have seldom been studied. We monitored carbonate – silicate reactions by combining high‐pressure experiments and synchrotron‐based x‐ray diffraction. Carbonates break down at moderate pressure and high temperature and CO2 is trapped at grain boundaries. Further isothermal compression yields melting, which may control continuous carbon introduction, first in the mantle wedge, and next, away from the wedge. Carbon presence has been discussed in a variety of magmatic contexts, under the oceanic lithosphere (hotspots, petit spots, fossil ridges). We suggest the presence of a global carbon‐rich layer under the oceanic lithosphere that is steadily fed by subduction processes. This layer can be the source of mechanical weakening of the lithosphere‐asthenosphere boundary under the oceans. Therefore, carbon‐induced compression melting may be a key mechanism of modern‐style plate tectonics.

Published
2021
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20. The diverse planetary ingassing/outgassing paths produced over billions of years magmatic activity

Author

Sara Vulpius, Fabrice Gaillard, Giovanni Ortenzi, Evelyn Füri, Yves Marrocchi, Lena Noack, Mohamed Ali Bouhifd, Valérie Malavergne, Mathieu Roskosz, Magma - UMR7327, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géomatériaux et Environnement (LGE ), Université Gustave Eiffel, Freie Universität Berlin, DLR Institute of Planetary Research, German Aerospace Center (DLR), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Astronomy and Astrophysics, Crust, Geodynamics, 01 natural sciences, Mantle (geology), Astrobiology, magmatic activity, Plate tectonics, Mantle convection, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Magma, outgassing, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, 010303 astronomy & astrophysics, Refractory (planetary science), Geology, Planetary differentiation, planetary atmospheres, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The C-H-O-N-S elements that constitute the outgassed atmosphere and exosphere have likely been delivered by chondritic materials to the Earth during planetary accretion and subsequently processed over billions of years of planetary differentiation. Although these elements are generally considered to be volatile, a large part of the accreted C-H-O-N-S on Earth must have been sequestered in the core and mantle, with the remaining part concentrated at the Earth’s surface (exosphere: $\text{atmosphere} + \text{ocean} + \text{crust}$ ). The likely reason for this is that, depending on the prevailing pressure (P), temperature (T) and oxidation state (oxygen fugacity, fO2) in the planet’s interior, the C-H-O-N-S elements can behave as siderophile, lithophile, refractory, magmatophile, or atmophile. It is not clear if these elements might be sequestered in the interiors of planets elsewhere, since the governing parameters of P-T-fO2 during the diverse magmatic processes controlling magmatic differentiation vary greatly over time and from planet to planet. The magma ocean outgassed the first atmosphere, which was probably also the largest in terms of mass, but its nature and composition remain poorly known. Meanwhile, a significant, but unknown, part of the accreted C-H-O-N-S elements was sequestered in the core. These will probably never be liberated into the atmosphere. A secondary atmosphere was then fuelled by volcanism, driven by mantle convection and most likely enhanced by plate tectonics. The Earth still has active volcanism, and the volume and volatile contents of its magma are closely linked to geodynamics. Earth’s volcanoes have long emitted relatively oxidized gases, in contrast to Mars and Mercury. Mantle oxidation state seems to increase with planetary size, although the role of plate tectonics in changing the Earth’s mantle oxidation state remains poorly understood. Water contents of magma from elsewhere in the solar system are not so different from those produced by the Earth’s depleted mantle. Other elements (e.g. N, S, C) are unevenly distributed. A great diversity of speciation and quantity of magmatic gas emitted is found in planetary systems, with the key inputs being: 1 – degassing of the magma ocean, 2 – mantle oxidation state (and its evolution), and 3 – plate tectonics (vs. other styles of mantle convection). Many other parameters can affect these three inputs, of which planetary size is probably one of the most important.

Published
2021
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21. High S and high CO2 contents in haplokimberlite: An experimental and Raman spectroscopic study

Author

Yann Morizet, Ida Di Carlo, Fabrice Gaillard, Chloé Larre, 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), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and SYSTER Program INSU-CNRS

Subjects
kimberlite, 020209 energy, CO2 and S dissolution, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Atmosphere, chemistry.chemical_compound, symbols.namesake, Geochemistry and Petrology, Oxidizing agent, 0202 electrical engineering, electronic engineering, information engineering, Solubility, Sulfate, 0105 earth and related environmental sciences, degassing, Sulfur, Geophysics, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], symbols, Saturation (chemistry), Raman spectroscopy, Kimberlite
Abstract

International audience; Sulfur is an important element present in natural kimberlites and along with CO2, S can play a role in the kimberlite degassing. We have investigated experimentally the change in S content and CO2 solubility in synthetic kimberlitic melts in response to a range of pressure (0.5 to 2.0 GPa) and temperature (1500 to 1525 °C). Several initial S concentrations were investigated ranging from 0 to 24000 ppm. The dissolved CO2 and S were determined by Raman spectroscopy and Electron Probe Micro-Analyses. Under the investigated oxidizing conditions (ΔFMQ + 1), S is dissolved in the glass only as S6+ forming sulfate molecular groups (SO42−). The measured S concentration in the glasses increases from 2900 to 22000 ppm. These results suggest that the experimental conditions were below saturation with respect to S and that the S solubility is higher than 22000 ppm for kimberlitic melts; regardless of the experimental conditions considered here. CO2 is dissolved as CO32− molecular groups. The CO2 solubility ranges from 3.0 to 11.3 wt% between 0.5 and 2.0 GPa. CO2 solubility is not affected by the presence of S; which suggests that SO42− and CO32− clusters have two distinct molecular environments not interacting together. This result implies that both CO2 and S are efficiently transported by kimberlitic melt from the upper mantle towards the atmosphere.

Published
2020
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22. Reply on the comment by X. Xue on «Towards the reconciliation of viscosity change and CO2-induced polymerization in silicate melt» by Yann Morizet, Michael Paris, David Sifré, Ida Di Carlo, Sandra Ory, and Fabrice Gaillard [chemical Geology 458, 38-47]

Author

Sandra Ory, David Sifré, Ida Di Carlo, Yann Morizet, Michael Paris, Fabrice Gaillard, Laboratoire de Planétologie et Géodynamique [UMR 6112] (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), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Université d'Orléans (UO)-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), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO)

Subjects
Polymer science, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geology, 010402 general chemistry, 010502 geochemistry & geophysics, 01 natural sciences, Silicate, 0104 chemical sciences, Viscosity, chemistry.chemical_compound, Polymerization, chemistry, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU]Sciences of the Universe [physics], ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2020
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23. Numerical modelling of erosion and assimilation of sulfur-rich substrate by martian lava flows: Implications for the genesis of massive sulfide mineralization on Mars

Author

Marco L. Fiorentini, Fabrice Gaillard, Raphael J. Baumgartner, David Baratoux, Centre for Exploration Targeting, The University of Western Australia (UWA), Institut Fondamental d'Afrique Noire (IFAN), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), Géosciences Environnement Toulouse (GET), 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)-Observatoire Midi-Pyrénées (OMP), 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 des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Métallogénie - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
chemistry.chemical_classification, Martian, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, Sulfide, Lava, Geochemistry, Astronomy and Astrophysics, Mars Exploration Program, Volcanism, 010502 geochemistry & geophysics, 01 natural sciences, Volcanic rock, chemistry, Space and Planetary Science, Hesperian, Sulfate assimilation, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Mantle-derived volcanic rocks on Mars display physical and chemical commonalities with mafic-ultramafic ferropicrite and komatiite volcanism on the Earth. Terrestrial komatiites are common hosts of massive sulfide mineralization enriched in siderophile-chalcophile precious metals (i.e., Ni, Cu, and the platinum-group elements). These deposits correspond to the batch segregation and accumulation of immiscible sulfide liquids as a consequence of mechanical/thermo-mechanical erosion and assimilation of sulfur-rich bedrock during the turbulent flow of high-temperature and low-viscosity komatiite lava flows. This study adopts this mineralization model and presents numerical simulations of erosion and assimilation of sulfide- and sulfate-rich sedimentary substrates during the dynamic emplacement of (channelled) mafic-ultramafic lava flows on Mars. For sedimentary substrates containing adequate sulfide proportions (e.g., 1 wt% S), our simulations suggest that sulfide supersaturation in low-temperature (1400°C). The precious-metals tenor in the derived immiscible sulfide liquids may be significantly upgraded as a result of their prolonged equilibration with large volumes of silicate melts along flow conduits. The influence of sulfate assimilation on sulfide supersaturation in martian lava flows is addressed by simulations of melt-gas equilibration in the C-H-O-S fluid system. However, prolonged sulfide segregation and deposit genesis by means of sulfate assimilation appears to be limited by lava oxidation and the release of sulfur-rich gas. The identification of massive sulfide endowments on Mars is not possible from remote sensing data. Yet the results of this study aid to define regions for the potential occurrence of such mineral systems, which may be the large canyon systems Noctis Labyrinthus and Valles Marineris, or the Hesperian channel systems of Mars’ highlands (e.g., Kasei Valles), most of which have been periodically draped by mafic-ultramafic lavas.

Published
2017
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24. Assimilation of sulfate and carbonaceous rocks: Experimental study, thermodynamic modeling and application to the Noril’sk-Talnakh region (Russia)

Author

Nicholas Arndt, Giada Iacono-Marziano, Ida Di Carlo, Clément Ferraina, Fabrice Gaillard, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ANR-12-JS06-0009,InterVol,Interprétation quantitative des interactions magma-roches sédimentaires par approche expérimentale: implications sur les émissions volcaniques de volatiles et la formation de gisements miniers.(2012), ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Métallogénie - UMR7327, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
Experimental petrology, 010504 meteorology & atmospheric sciences, Sulfide, Geochemistry, chemistry.chemical_element, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, Noril’sk-Talnakh intrusions, Geochemistry and Petrology, Ultramafic rock, Organic matter, Sulfate assimilation, Sulfate, 0105 earth and related environmental sciences, chemistry.chemical_classification, Olivine, Anhydrite, Geology, Sulfur, Magma-sediment interaction, chemistry, 13. Climate action, Magmatic sulfides, engineering, Economic Geology, Thermodynamic modeling, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; Most of the intrusions in the Noril’sk-Talnakh region (Siberia) are hosted in thick sedimentary sequences including abundant evaporitic and terrigenous sedimentary rocks. Three mafic-ultramafic intrusions in this region contain unusually thick massive sulfide deposits, which represent one of the world's largest economic concentrations of Ni, Cu and PGE. The interaction of Siberian magmas with sulfate and organic matter-rich sedimentary rocks has been proposed as a possible mechanism for the origin of these exceptional sulfide deposits but the interaction process and the reaction paths have never been fully investigated. Here we clarify, by both experimental petrology and thermodynamic modeling, how sulfate and organic matter assimilation occur in mafic-ultramafic magmas, affecting magma composition, crystallization and sulfide saturation.Interaction experiments were conducted at conditions relevant to the emplacement of Noril’sk type intrusions (1200 °C, ∼80 MPa) to simulate the assimilation of sulfate and/or organic compounds by ultramafic magmas. We used a picrite from Noril’sk1 intrusion, and coal and anhydrite from the area as starting materials. The experimental results show that the incorporation of anhydrite into the magma occurs by chemical dissolution in the melt, which increases the magma's sulfur content, but suppresses sulfide saturation and reduces olivine crystallization. Extreme assimilation leads to sulfate saturation in the magma and high dissolved sulfur contents of 0.9±0.1 wt.% S. Conversely, coal assimilation promotes sulfide segregation and magma crystallization, while decreasing the dissolved H2O content of the melt and increasing the amount of coexisting fluid phase.We also employed gas-melt thermodynamic calculations to quantify the effect of these assimilations on the redox conditions and the S content of the magma, and investigate the role of temperature, pressure, and initial gas content of the magma in the assimilation process. We quantify how sulfate assimilation strongly oxidizes the magma and increases its S content; both effects are intensified by increasing pressure (from 50 to 100 MPa in this study), decreasing temperature (from 1350 to 1200 °C in this study), and decreasing amounts of fluid phase initially coexisting with the magma (from 2 to 0 wt.%). The interaction with organic matter (CH in this study) induces a strong reduction of the magma, even for extremely low degrees of assimilation (few tenths of wt.%), and the dehydration of the melt.We therefore suggest that in the Noril’sk-Talnakh district (1) additional S was supplied to mantle derived magmas by the assimilation of evaporitic rocks, and was transported during magma ascent in the form of dissolved, oxidized S; (2) a substantial reduction of the magma inducing sulfide segregation and important crystallization then occurred due to the interaction with carbonaceous sediments. This mechanism can potentially produce massive sulfide deposits by important sulfate assimilation (locally higher than 3 wt.% CaSO4) and minor organic matter assimilation (few tenths of wt.% CH); however, if one of the two steps does not occur, or the assimilation in (1) is not large enough, disseminated sub economic or no sulfide deposits are produced. We conclude that exceptional conditions favoring substantial assimilation of sediments are needed to generate exceptional ore deposits like those of the Noril’sk-Talnakh district.

Published
2017
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25. Unravelling partial melt distribution in the oceanic low velocity zone

Author

Mickael Laumonier, Emmanuel Gardés, Fabrice Gaillard, Malcolm Massuyeau, Matériaux, Défauts et IRradiations (MADIR), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Department of Geology [University of Johannesburg], University of Johannesburg [South Africa] (UJ), Magma - UMR7327, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), ANR-11-EQPX-0020,GENESIS,Groupe d'Etudes et de Nanoanalyses des Effets d'IrradiationS(2011), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), University of Johannesburg (UJ), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
low velocity zone, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Wave velocity, distribution and dynamics of volatiles and melt in the upper mantle, mantle incipient melting, 010502 geochemistry & geophysics, 01 natural sciences, volatile-rich melt interconnection in mantle rocks, Mantle (geology), Geophysics, Shear (geology), Rheology, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Seismic velocity, Lithosphere, Earth and Planetary Sciences (miscellaneous), Low-velocity zone, Petrology, Geology, 0105 earth and related environmental sciences
Abstract

Co-auteur étranger; International audience; The widespread low seismic velocity zone (LVZ) in the shallow oceanic mantle has long been debated in terms of mantle melting. At LVZ depths, volatiles (CO2 and H2O) are present in minute amounts, which implies mantle incipient melting down to below 1000 °C with the production of minute amounts of volatile-rich melt, well below 1 vol.%. However, melt compositions and distributions in the incipient melting regime have only been inferred from experiments departing from actual mantle conditions. Here, we experimentally reproduce incipient melting by re-equilibrating a naturally CO2- and H2O-bearing mantle rock at mantle temperatures and pressure. By using cutting-edge microscopy characterizations, we evidence that minute amounts of volatile-rich melts fully interconnect in mantle rocks down to lithospheric temperatures, enabling thus the modification of geophysical signals from the mantle. These findings and the correspondence of the domain of local, sharp drops in shear wave velocity (Vs) with the domain of (CO2+H2O)-melting in the LVZ strongly supports that these geophysical anomalies relate to mantle melting. Geophysical surveys image in situ the very low and highly heterogeneous distribution of melt in the mantle generated by the very low and highly heterogeneous distribution of volatiles probed by surficial geochemical surveys. The global-scale geophysical signature of the LVZ appears mainly unaffected because the average background melt fraction is very low, estimated at ∼0.03-0.05 vol.% melt. However, enhanced geophysical signals arise from sporadic, localized areas where melt fraction is increased, such as the ∼0.2 vol.% melt estimated for detecting sharp Vs drops using SS precursors. In-depth deciphering of the dynamics of melt and volatiles in the LVZ calls for investigations on the seismic velocity, permeability and rheology of partially molten mantle rocks covering the diversity of mantle melt compositions, fractions and temperatures.

Published
2020
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26. Possible Atmospheric Diversity of Low Mass Exoplanets – Some Central Aspects

Author

Emeline Bolmont, Benjamin Charnay, Mareike Godolt, François Forget, John Lee Grenfell, Martin Turbet, Óscar Carrión-González, Jérémy Leconte, Lena Noack, Heike Rauer, Feng Tian, Fabrice Gaillard, 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Zentrum für Astronomie und Astrophysik [Berlin] (ZAA), Technische Universität Berlin (TU), Institut für Geologische Wissenschaften, Freie Universität Berlin, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Observatoire de Paris, Université Paris sciences et lettres (PSL), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
Solar System, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, review, Exoplanetology, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), 01 natural sciences, diversity, Astrobiology, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric models, exoplanetary, Astronomy and Astrophysics, Exoplanet, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, atmospheres, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Astrophysics - Earth and Planetary Astrophysics, Diversity (politics), Exosphere
Abstract

International audience; Exoplanetary science continues to excite and surprise with its rich diversity. We discuss here some key aspects potentially influencing the range of exoplanetary terrestrial-type atmospheres which could exist in nature. We are motivated by newly emerging observations, refined approaches to address data degeneracies, improved theories for key processes affecting atmospheric evolution and a new generation of atmospheric models which couple physical processes from the deep interior through to the exosphere and consider the planetary-star system as a whole. Using the Solar System as our guide we first summarize the main processes which sculpt atmospheric evolution then discuss their potential interactions in the context of exoplanetary environments. We summarize key uncertainties and consider a diverse range of atmospheric compositions discussing their potential occurrence in an exoplanetary context.

Published
2020
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27. Geoscience for understanding habitability in the solar system and beyond

Author

Lena Noack, Dennis Höning, Tim Van Hoolst, Vinciane Debaille, Tilman Spohn, Emmanuelle Javaux, Heike Rauer, Özgür Karatekin, Kai Wünnemann, Manuel Scherf, Alessandro Morbidelli, Paul J. Tackley, Véronique Dehant, Vera Dobos, Fabrice Gaillard, Steven Goderis, Cedric Gillmann, John Lee Grenfell, Royal Observatory of Belgium [Brussels] (ROB), Université Libre de Bruxelles (ULB), Laboratoire G-Time, Université libre de Bruxelles (ULB), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Vrije Universiteit Brussel (VUB), Extrasolare Planeten und Atmosphären, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR)- Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire de Paléobotanique, Paléopalynologie et Micropaléontologie (LPPM), Université de Liège, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Werkzeugmaschinen und Fabrikbetrieb (IWF), Fakultät Verkehrs- und Maschinensysteme, Technische Universität Berlin (TU)-Technische Universität Berlin (TU), Institut für Planetologie [Münster], Westfälische Wilhelms-Universität Münster (WWU), Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), European Project: 308074,EC:FP7:ERC,ERC-2012-StG_20111012,ELITE(2013), UCL - SST/ELI/ELIC - Earth & Climate, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Technical University of Berlin / Technische Universität Berlin (TU)-Technical University of Berlin / Technische Universität Berlin (TU), Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Chemistry, Analytical, Environmental & Geo-Chemistry, Royal Observatory of Belgium [Brussels], Université Libre de Bruxelles [Bruxelles] (ULB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Vrije Universiteit [Brussels] (VUB), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Berlin (TUB)-Technische Universität Berlin (TUB), Department of Earth Sciences [ETH Zürich] (D-ERDW), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)

Subjects
expoplanets, Extrasolare Planeten und Atmosphären, Solar System, 010504 meteorology & atmospheric sciences, Earth science, Habitability, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Physics::Geophysics, Planetenphysik, Geoscience, Planet, Planet evolution, 0103 physical sciences, hability, 010303 astronomy & astrophysics, Astrophysique, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Planetary habitability, Exoplanets, Leitungsbereich PF, early earth-planet, Biosphere, Astronomy and Astrophysics, Early Earth, Astronomie, Exoplanet, Sciences de l'espace, habitability, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Terrestrial planet, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Hydrosphere
Abstract

This paper reviews habitability conditions for a terrestrial planet from the point of view of geosciences. It addresses how interactions between the interior of a planet or a moon and its atmosphere and surface (including hydrosphere and biosphere) can affect habitability of the celestial body. It does not consider in detail the role of the central star but focusses more on surface conditions capable of sustaining life. We deal with fundamental issues of planetary habitability, i.e. the environmental conditions capable of sustaining life, and the above-mentioned interactions can affect the habitability of the celestial body. We address some hotly debated questions including: How do core and mantle affect the evolution and habitability of planets?What are the consequences of mantle overturn on the evolution of the interior and atmosphere?What is the role of the global carbon and water cycles?What influence do comet and asteroid impacts exert on the evolution of the planet?How does life interact with the evolution of the Earth’s geosphere and atmosphere?How can knowledge of the solar system geophysics and habitability be applied to exoplanets? In addition, we address the identification of preserved life tracers in the context of the interaction of life with planetary evolution., SCOPUS: re.j, info:eu-repo/semantics/published

Published
2019
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28. Nitrogen solubility in basaltic silicate melt - Implications for degassing processes

Author

Fabrice Gaillard, Aneta Slodczyk, Yves Marrocchi, Fabien Bernadou, Evelyn Füri, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE31-0021,GASTON,Les constituants volatils dans les processus magmatiques du noyau aux atmosphères(2018), and ANR-11-EQPX-0036,PLANEX,Planète Expérimentation: simulation et analyse in-situ en conditions extrêmes(2011)

Subjects
010504 meteorology & atmospheric sciences, Nitrogen, Analytical chemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, chemistry.chemical_element, 010502 geochemistry & geophysics, 01 natural sciences, Atmosphere, chemistry.chemical_compound, Degassing, Geochemistry and Petrology, Mineral redox buffer, IHPV, Fourier transform infrared spectroscopy, Solubility, Oxygen fugacity, 0105 earth and related environmental sciences, Geology, Silicate, Pressure vessel, Secondary ion mass spectrometry, chemistry, [SDU]Sciences of the Universe [physics], 13. Climate action, SIMS
Abstract

International audience; The distribution of nitrogen between the different terrestrial reservoirs (core-mantle-atmosphere) and how this may have changed since the earliest planetary stages is uncertain. In particular, the primordial degassing processes of the magma ocean and its role in the formation of the atmosphere remains to be quantified. Since no geological samples can capture this early degassing process, we need to go through the thermodynamic modeling of the nitrogen solubility in silicate melt. We hence performed experiments on basaltic samples at fluid saturation in the C-H-O-N system, using an Internally Heated Pressure Vessel (IHPV) and Piston Cylinder (PC) in the pressure range 0.8 kbar to 10 kbar, temperature between 1200 and 1300 °C, and a wide range of fO2 conditions from IW + 4.9 to IW-4.7 (IW standing for the Iron-Wustite redox buffer). The nitrogen concentration in the quenched silicate melts at fluid saturation was analysed by secondary ion mass spectrometry (SIMS), and the speciation of the dissolved C-O-H species was determined by Fourier transform infrared spectroscopy (FTIR). We identified two nitrogen species in the silicate melt: N2 dominating at fO2 > IW and N3− at lower fO2. Using these data and a database constraining nitrogen concentration at fluid saturation from 1 bar to 10 kbar pressure, we calibrated a solubility law for nitrogen in basalts defining its P-T-fO2 dependences. This model expands the model of Libourel et al. (2003) to high pressure and higher C-O-H activities. It can be used to investigate the nitrogen degassing processes for different pressure, temperature and fO2 conditions relevant to planetary accretion and modern volcanism.

Published
2021
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29. MAGLAB: A computing platform connecting geophysical signatures to melting processes in Earth's mantle

Author

David Sifré, Grégory Rogerie, Emmanuel Gardés, Emmanuel Le Trong, Fabrice Gaillard, Sonja Aulbach, Sebastian Tappe, Malcolm Massuyeau, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), University of Johannesburg (UJ), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institut für Geowissenschaften [Frankfurt am Main], Goethe-Universität Frankfurt am Main, European Synchrotron Radiation Facility (ESRF), ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), University of Johannesburg [South Africa] (UJ), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Petrological-geophysical modeling, CO 2 -H 2 O volatiles, 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Lithosphere, Hotspot (geology), Intraplate magmas, 0105 earth and related environmental sciences, Lithosphere-Asthenosphere boundary, Peridotite, Basalt, Partial melting, Astronomy and Astrophysics, Geophysics, Upper mantle, Melt fraction-composition, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Lithosphere-asthenosphere boundary, Kimberlite, Geology
Abstract

International audience; Decompression melting of the upper mantle produces magmas and volcanism at the Earth's surface. Experimental petrology demonstrates that the presence of CO2 and H2O enhances peridotite melting anywhere within the upper mantle down to approximately 200–300 km depth. The presence of mantle melts with compositions ranging from carbonate-rich to silicate-rich unavoidably affects the geophysical signals retrieved from Earth's mantle. Geochemical investigations of erupted intraplate magmas along with geophysical surveys allow for constraining the nature and volume of primary melts, and a sound formalism is required to integrate these diverse datasets into a realistic model for the upper mantle including melting processes. Here, we introduce MAGLAB, a model developed to calculate the composition and volume fraction of melts in the upper mantle, together with the corresponding electrical conductivity of partially molten mantle peridotites at realistic pressure-temperature conditions and volatile contents. We use MAGLAB to show how the compositions of intraplate magmas relate to variations in lithosphere thickness. Progressive partial melting of a homogeneous peridotitic mantle source can in theory create the diversity of compositions observed among the spectrum of intraplate magma types, with kimberlite melts beneath thick continental shields, alkaline magmas such as melilitite, nephelinite and basanite beneath thinner continents and relatively old plus thick oceanic lithospheres, and ‘regular’ basalts beneath the youngest and thinnest oceanic lithospheres as well as beneath significantly thinned continental lithospheres. MAGLAB calculations support recent experimental findings about the role of H2O in the upper mantle on producing primary kimberlitic melts in addition to CO2. We demonstrate the robustness of MAGLAB calculations by reproducing the compositions of erupted melts as well as associated mantle electrical conductivities beneath the Society hotspot in the Pacific Ocean. A comparison of our simulations with magnetotelluric surveys at various oceanic settings shows that the heterogeneities in electrical conductivity of Earth's upper mantle are related to variations in volatile content via the presence of small (generally <

Published
2021
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30. Sulfur on Mars from the Atmosphere to the Core

Author

Fabrice Gaillard, Penelope L. King, and Heather B. Franz

Subjects
Martian, Atmosphere, chemistry, Meteorite, Martian surface, chemistry.chemical_element, Environmental science, Mars Exploration Program, Life on Mars, Sulfur, Space exploration, Astrobiology
Abstract

Observations of the Martian surface from orbiting spacecraft and in situ landers and rovers, as well as analyses of Martian meteorites in terrestrial laboratories, have consistently indicated that Mars is a sulfur-rich planet. The global inventory of sulfur, from the atmosphere to the core, carries widespread implications of potential geophysical, geochemical, climatological, and astrobiological significance. For example, the sulfur content of the core carries implications for core density; the speciation of igneous sulfur minerals reflects the oxidation state of the magma from which they formed; sulfur-bearing gases may have exerted control on the temperatures at the surface of early Mars; and the widespread availability of sulfur on Mars would have provided an abundant source for energy and nutrients to fuel sulfur-metabolizing microbes, such as those that arose during the emergence of primitive life on Earth. Here we provide an overview of Martian sulfur and its relevance to these areas of interest, including a discussion of analytical techniques and results acquired by space missions and meteorite analyses to date. We review current studies modeling the potential effects of sulfur-bearing gases on the past Martian climate and possible constraints on atmospheric composition implied by sulfur isotopic data. We also explore the importance of sulfur to the search for extinct or extant life on Mars. Finally, we summarize a few areas of interest to future work, including advances in space exploration technology and preparation for Mars sample return.

Published
2019
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31. X-ray absorption spectroscopic investigation of the Ca and Mg environments in CO2-bearing silicate glasses

Author

Fabrice Gaillard, Delphine Vantelon, Erwan Le Menn, Chloé Larre, Marion Rivoal, Yann Morizet, Nicolas Trcera, 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), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Métallogénie - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Magma - UMR7327

Subjects
X-ray absorption spectroscopy, 010504 meteorology & atmospheric sciences, Absorption spectroscopy, Extended X-ray absorption fine structure, Coordination number, Analytical chemistry, Geology, 010502 geochemistry & geophysics, 01 natural sciences, CO2 dissolution mechanism, Silicate, XANES, chemistry.chemical_compound, EXAFS, CO2 content, chemistry, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Absorption (chemistry), Mg and Ca structural environment, 0105 earth and related environmental sciences
Abstract

International audience; Recent investigation showed that the CO2 solubility in silicate melts is strongly affected by the #Mg (MgO/MgO + CaO). CO2 solubility is decreasing with increasing #Mg implying that CO2 molecules dissolves in the vicinity of Ca atoms to form CO32– molecular groups. We have investigated several CO2-bearing (up to 17.2 wt%) silicate glasses using X-ray Absorption Spectroscopy (XAS) at the Mg and Ca K-edge in order to determine the structural environments of Mg2+ and Ca2+ cations. Analyses of the Mg XANES region show that the Mg environment is not affected by the presence of CO2 dissolved as CO32– groups regardless of the CO2 content. The Mg K-edge EXAFS simulations and XANES modelling show that the average MgO distance is close to 2 Å and the average Mg coordination is close to 6.On the contrary, the position of the Ca XANES peak main resonance related to first-coordination shell is negatively correlated with the CO2 content and shifts from 4051.4 to 4050.8 eV with CO2 increasing from 0 to 17.2 wt%. The Ca EXAFS simulations showed that CaO average distance is longer (~2.5 Å) than the MgO distance. Furthermore, we observed that the Ca coordination number is positively correlated with the CO2 content: Ca coordination number increases from 7 to 9 for CO2 content changing from 0 to 17.2 wt%.Mg and Ca XAS results suggest that CO32– groups are dissolved in the vicinity of Ca2+ cations and not in the surrounding of Mg2+ cations which environment remains unaffected by CO2 dissolution. The tighter Mg atomic environment as well as the lower coordination number for Mg cations as compared to Ca atomic environment could explain such behaviour. One implication of this result is the lower CO2 transport capacity for Mg-rich silicate melts such as komatiites or kimberlites.

Published
2019
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32. Experimental constraints on the fate of H and C during planetary core-mantle differentiation. Implications for the Earth

Author

Chloé Fourdrin, Hicham Khodja, Svyatoslav Shcheka, Caroline Raepsaet, Suzy Surblé, Damien Deldicque, Mélissa Poncet, Fabrice Gaillard, Valérie Malavergne, David Sifré, Hélène Bureau, Laboratoire Géomatériaux et Environnement (LGE), Université Paris-Est Marne-la-Vallée (UPEM), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etudes des Eléments Légers (LEEL - UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Bayerrisches Geoinstitut (BGI), Universität Bayreuth, Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris)

Subjects
010504 meteorology & atmospheric sciences, Hydrogen, Analytical chemistry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Redox, Mantle (geology), Planet, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Chemistry, Planetary core, Core segregation, Astronomy and Astrophysics, Primitive Earth, Carbon, Planetary differentiation, 13. Climate action, Space and Planetary Science, High pressure, Order of magnitude
Abstract

International audience; Hydrogen (H) and carbon (C) have probably been delivered to the Earth mainly during accretion processes at High Temperature (HT) and High Pressure (HP) and at variable redox conditions. We performed HP (1 – 15 GPa) and HT (1600 – 2300°C) experiments, combined with state-of-the-art analytical techniques to better understand the behavior of H and C during planetary differentiation processes. We show that increasing pressure makes H slightly siderophile and slightly decreases the highly siderophile nature of C. This implies that the capacity of a growing core to retain significant amounts of H or C is mainly controlled by the size of the planet: small planetary bodies may retain C in their cores while H may have rather been lost in space; larger bodies may store both H and C in their cores. During the Earth's differentiation, both C and H might be sequestrated in the core. However, the H content of the core would remain one or two orders of magnitude lower than that of C since the (H/C)core ratio might range between 0.04 and 0.27.

Published
2019
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33. Evidence for a persistent magma reservoir with large melt content beneath an apparently extinct volcano

Author

Fabrice Gaillard, Ozge Karakas, Olivier Bachmann, Ioan Seghedi, Réka Lukács, Szabolcs Harangi, Thierry Menand, Mickael Laumonier, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), MTA-ELTE Research Group for Geology, Geophysics and Space Sciences, Eötvös Loránd University (ELTE)-Hungarian Academy of Sciences (MTA), Institute of Geodynamics of the Romanian Academy, Romanian Academy, ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Hungarian Academy of Sciences (MTA)-Eötvös Loránd University (ELTE)

Subjects
in-situ electrical-conductivity measurement, 010504 meteorology & atmospheric sciences, Lava, Geochemistry, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Silicic, Solidus, 010502 geochemistry & geophysics, 01 natural sciences, mush petrology, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, seemingly inactive volcano, magma storage, numerical simulation, geophysical interpretation, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Geophysics, Volcano, 13. Climate action, Space and Planetary Science, Magma, Geology
Abstract

co-auteur étranger; International audience; Most active volcanoes display eruption frequencies of 10-1000s years but a class of volcanic systems has extremely long repose-time (>10's kyr), and are deemed as extinct. Yet, some reawaken, posing a particular threat because little is known about the way they endure and stir back to life. Reawakening primarily depends on the nature of the subvolcanic magma reservoir, especially the presence and distribution of melt. Here, we integrate petrology, thermobarometry, thermomechanical models, geophysics and in situ electrical conductivity measurements to show that the magma storage beneath Ciomadul, a seemingly inactive volcano in eastern-central Europe that last erupted 30 ka, may still hold 20 to 58 km3 of water-rich silicic melt, constituting up to 20-58% in parts of the upper crustal crystal mush body. Such a melt volume exceeds the volume of erupted lava over the entire history of the volcano. This illustrates the important longevity of a magmatic reservoir at temperature above the solidus, which implies that there is still a potential for rapid mush rejuvenation. That a seemingly dead volcano like Ciomadul is actually capable of erupting in the future calls for renewed attention to “inactive” volcanoes worldwide and perhaps for a redefinition of their activity/inactivity status.

Published
2019
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34. List of Contributors

Author

John C. Bridges, Frances E.G. Butcher, Stephen M. Clifford, Susan J. Conway, William H. Farrand, Justin Filiberto, Heather B. Franz, Fabrice Gaillard, Ralf Gellert, Leon J. Hicks, Bradley L. Jolliff, Penelope L. King, Andrew H. Knoll, Samuel P. Kounaves, Jérémie Lasue, Paul R. Mahaffy, Nicolas Mangold, Amy C. McAdam, Francis M. McCubbin, Scott M. McLennan, Douglas W. Ming, David W. Mittlefehldt, John F. Mustard, Elizabeth A. Oberlin, Karen Olsson-Francis, Ulrich Ott, Susanne P. Schwenzer, Brad Sutter, Timothy D. Swindle, G. Jeffrey Taylor, Allan H. Treiman, Tomohiro Usui, and Albert S. Yen

Published
2019
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35. New aspects of magma storage and transfer

Author

Fabrice Gaillard, Bruno Scaillet, and Laurent Arbaret

Subjects
Global and Planetary Change, General Earth and Planetary Sciences, Petrology, Magma (computer algebra system), computer, Geology, computer.programming_language
Published
2019
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36. The molecular structure of melts along the carbonatite–kimberlite–basalt compositional joint: CO 2 and polymerisation

Author

Pierre Florian, Bertrand Guillot, Nicolas Sator, Yann Morizet, Yves Moussallam, Fabrice Gaillard, Giada Iacono-Marziano, Burkhard C. Schmidt, D Corradini, Rodolphe Vuilleumier, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Geosciences Research Division [La Jolla], Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California-University of California [San Diego] (UC San Diego), University of California-University of California, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Département de Chimie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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 de Physique Théorique de la Matière Condensée (LPTMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Mineralogy Department GZG, Georg-August-University [Göttingen], HPC resources from GENCI–[TGCC/CINES/IDRIS] (Grants 2013-082309, 2014-082309 and 2015-082309)., ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC)-University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Georg-August-University = Georg-August-Universität Göttingen

Subjects
kimberlite, 010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), chemistry.chemical_compound, Geochemistry and Petrology, Asthenosphere, Earth and Planetary Sciences (miscellaneous), Metasomatism, glass, 0105 earth and related environmental sciences, Peridotite, transitional melt, Partial melting, Silicate, Geophysics, speciation, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Carbonate, CO2, Kimberlite, polymerisation, Geology
Abstract

International audience; Transitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remained largely unstudied. Their molecular structure has remained elusive in part because these melts are difficult to quench to glass. Here we use FTIR, Raman, 13C and 29Si NMR spectroscopy together with First Principle Molecular Dynamic (FPMD) simulations to investigate the molecular structure of transitional melts and in particular to assess the effect of CO2on their structure. We found that carbon in these glasses forms free ionic carbonate groups attracting cations away from their usual ‘depolymerising’ role in breaking up the covalent silicate network. Solution of CO2in these melts strongly modifies their structure resulting in a significant polymerisation of the aluminosilicate network with a decrease in NBO/Si of about 0.2 for every 5 mol% CO2dissolved.This polymerisation effect is expected to influence the physical and transport properties of transitional melts. An increase in viscosity is expected with increasing CO2content, potentially leading to melt ponding at certain levels in the mantle such as at the lithosphere–asthenosphere boundary. Conversely an ascending and degassing transitional melt such as a kimberlite would become increasingly fluid during ascent hence potentially accelerate. Carbon-rich transitional melts are effectively composed of two sub-networks:a carbonate and a silicate one leading to peculiar physical and transport properties.

Published
2016
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37. CO2 solubility in kimberlite melts

Author

Yves Moussallam, Yann Morizet, Malcolm Massuyeau, Fabrice Gaillard, and Mickael Laumonier

Subjects
Quenching, Buoyancy, Mineralogy, Thermodynamics, Geology, engineering.material, CO2 content, 13. Climate action, Geochemistry and Petrology, Magma, Carbonatite, engineering, Solubility, Kimberlite, Chemical composition
Abstract

Carbon dioxide is the most abundant volatile in kimberlite melts and its solubility exerts a prime influence on the melt structure, buoyancy, transport rate and hence eruption dynamics. The actual primary composition of kimberlite magma is the matter of some debate but the solubility of CO2 in kimberlitic melts is also poorly constrained due to difficulties in quenching these compositions to a glass that retains the equilibrium CO2 content. In this study we used a range of synthetic, melt compositions with broadly kimberlitic to carbonatitic characteristics which can, under certain conditions, be quenched fast enough to produce a glass. These materials are used to determine the CO2 solubility as a function of chemical composition and pressure (0.05–1.5 GPa). Our results suggest that the solubility of CO2 decreases steadily with increasing amount of network forming cations from ~ 30 wt.% CO2 at 12 wt.% SiO2 down to ~ 3 wt.% CO2 at 40 wt.% SiO2. For low silica melts, CO2 solubility correlates non-linearly with pressure showing a sudden increase from 0.1 to 100 MPa and a smooth increase for pressure > 100 MPa. This peculiar pressure–solubility relationship in low silica melts implies that CO2 degassing must mostly occur within the last 3 km of ascent to the surface having potential links with the highly explosive nature of kimberlite magmas and some of the geo-morphological features of their root zone. We present an empirical CO2 solubility model covering a large range of melt composition from 11 to 55 wt.% SiO2 spanning the transition from carbonatitic to kimberlitic at pressures from 1500 to 50 MPa.

Published
2015
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38. The effect of pressure and water concentration on the electrical conductivity of dacitic melts: Implication for magnetotelluric imaging in subduction areas

Author

Fabrice Gaillard, Mickael Laumonier, David Sifré, Bayerisches Geoinstitut (BGI), Universität Bayreuth, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Mantle wedge, Subduction, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Mineralogy, Geology, Conductivity, Thermal diffusivity, Mantle (geology), 13. Climate action, Geochemistry and Petrology, Electrical resistivity and conductivity, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Slab, Water content
Abstract

International audience; Silica-rich hydrous magmas are commonly stored in crustal reservoirs, but are also present at mantle depths in subduction contexts as a result of slab melting in the presence of considerable amounts of water and other vol-atile species. Magnetotelluric surveys frequently identify highly conductive zones at crustal or mantle depths possibly revealing the presence of such silica-rich melts and this can be used to trace the cycling of water in sub-duction zones and its relationship with arc-magmatism. The achievement of such a purpose is impeded by poor knowledge of the electrical conductivity of both dry and hydrous silica-rich melts at pressure. To fill this gap, we performed in situ electrical conductivity measurements on a dacitic melt using a 4-wire set up to 1300 °C, 3.0 GPa and H 2 O content up to 12 wt.%. Melt conductivity is strongly correlated with its water content, and we reveal a complex effect of pressure being relatively small at low water contents and major at high water contents: with increasing water content, the activation volume ranges between 4 (dry) and 25 cm 3 /mol (H 2 O = 12 wt.%) and the activation energy decreases from 96 kJ (dry) to 62 kJ (12 wt.% H 2 O). By comparison with diffusivity data, so-dium appears to be the main charge carrier, even at high (12 wt.%) water content. A T–P–[H 2 O] model predicting the conductivity of dacitic melts shows that crustal and mantle wedge conductive bodies can be interpreted by the presence of silica-rich, hydrous, partially crystallized magma.

Published
2015
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39. Experimental simulation and predictive modelling of rare earth element enrichment in carbonatites and alkaline magmas

Author

Johann Tuduri, Zineb Nabyl, Fabrice Gaillard, Malcolm Massuyeau, Giada Iacono-Marziano, Jérémie Melleton, Laurent Bailly, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Department of Geology [University of Johannesburg], and University of Johannesburg (UJ)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; Carbonatites and alkaline magmas are key pieces of the deep carbon cycle and constitute one of the principal resources of rare metals including REE. Several experimental studies have tackled the rare metal partitioning between immiscible carbonate and silicate liquids (Martin et al. 2013; Veskler et al. 1998, 2012). They show negative to massive enrichments in the carbonate liquid. However, no prevailing cause has been clearly isolated as such enrichments can be ruled by experimental conditions (P, T, ƒO 2), melt compositions (water and alkali contents), or technical issues such as unequilibrated experiments. The aim of this study is to simulate, by HP-HT experiments in the nephelinite-carbonatite system, crystal fractionation and immiscibility between carbonate and silicate liquids, in order to assess the factors ruling REE enrichment during the differentiation of alkaline magmas. Thirty experimental charges were synthetized using piston-cylinder and internally heated pressure vessel. The partitioning of REE between carbonate liquids, silicate liquids and crystals (pyroxene, calcite, nephelinite, perovskite, titanite) has been characterized. REE partition coefficients between carbonate and silicate liquid increase while Ca partition coefficient increases, suggesting that both have the same behavior. Also, the more the silicate liquid is polymerized, the more REE are concentrated into carbonate liquids. The Ca partition coefficient has been thus calibrated by an empirical model based on the silicate melt composition. This study reveals the optimum conditions for which carbonatite melts get enriched by >10 times with respect to the residual silicate melts. This predictive approach may serve as guide for prospection of REE-enriched carbonatites.

Published
2018

40. Publisher Correction: Melting conditions in the modern Tibetan crust since the Miocene

Author

Mickael Laumonier, Guillaume Richard, Xiaosong Yang, Bruno Scaillet, Fabrice Gaillard, Leїla Hashim, Arnaud Villaros, Laurent Jolivet, Martyn Unsworth, Jinyu Chen, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), China Earthquake Administration (CEA), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Multidisciplinary, Published Erratum, media_common.quotation_subject, Science, General Physics and Astronomy, Crust, General Chemistry, Geodynamics, Legend, General Biochemistry, Genetics and Molecular Biology, GeneralLiterature_MISCELLANEOUS, Paleontology, [SDU]Sciences of the Universe [physics], ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, lcsh:Q, lcsh:Science, Geology, media_common
Abstract

International audience; The original PDF version of this Article contained an error in which Fig. 3 and its legend were omitted and Equations 5 and 6 contained errors.This has been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.

Published
2018
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41. Volcanic gases

Author

Alessandro Aiuppa, Fabrice Gaillard, Aiuppa, Alessandro, and Gaillard, Fabrice

Subjects
010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Earth and Planetary Sciences (all), 0105 earth and related environmental sciences
Published
2018

43. Carbon dioxide in silica-undersaturated melt Part II: Effect of CO 2 on quenched glass structure

Author

Fabrice Gaillard, Michael Paris, Yann Morizet, and Bruno Scaillet

Subjects
Materials science, Silicon, Mineralogy, chemistry.chemical_element, Degree of polymerization, Silicate, chemistry.chemical_compound, chemistry, Polymerization, Geochemistry and Petrology, Aluminosilicate, Physical chemistry, Molecule, Solubility, Dissolution
Abstract

Despite CO 2 is the second most abundant volatile species implied in magmatic systems, its impact on the molecular structure of aluminosilicate glasses in complex systems is currently not well-constrained. Inasmuch, whether CO 2 induces an increase in glass polymerization or not is yet not clear for complex glass compositions. Using the set of nephelinite glass samples investigated in Part I (Morizet et al., 2014), in which the CO 2 solubility and speciation have been constrained as a function of the #K (molar K 2 O/K 2 O + Na 2 O), we have conducted a thorough investigation of the change in the silicate network structure associated to CO 2 dissolution. The change in silicate structure has been studied as a function of volatiles solubility (CO 2 up to 4.5 wt.%, H 2 O up to 3 wt.%) as well as a function of the #K (between 0 and 0.75) of the glasses. We used 29 Si Solid-State NMR for probing the silicon local environment in the quenched glasses. We observe that in such depolymerized nephelinite compositions the exchange between Na and K in volatile-free glasses induces a change in the glass structure attributed to the Mixed Alkali Effect (MAE) invoked in previous works. The observed changes might be related to geometric changes in the glass structure (change in network species bond lengths or angles). The addition of H 2 O only produces a negligible change in the degree of polymerization being probed by the constant NBO/T (Non-Bridging Oxygen per Tetrahedron) as H 2 O is added to volatile-free glasses. In contrast, we observed that the addition of CO 2 induces a strong change in the glass structure which might be interpreted as an increase in polymerization. Alternatively, considering the identified CO 2 dissolution mechanism (mostly as non-bridging carbonates units), the glass structure changes might reflect an apparent glass polymerization through the creation of Si–O–C bonds rather a true polymerization through the creation of Si–O–Si bonds.

Published
2014
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44. A relatively reduced Hadean continental crust and implications for the early atmosphere and crustal rheology

Author

Fabrice Gaillard, Xiaozhi Yang, Bruno Scaillet, State Key Laboratory for Mineral Deposits Research, Nanjing University (NJU), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Basalt, Underplating, [SDE.MCG]Environmental Sciences/Global Changes, Hadean, Continental crust, Archean, Geochemistry, early atmosphere, Crust, zircon, Early Earth, Igneous rock, Geophysics, Hadean continental crust, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Earth and Planetary Sciences (miscellaneous), oxidation state, impacts, Geology
Abstract

International audience; It is widely believed that the Earth was strongly reduced during its early accretion, however, the transition from the reduced state that prevailed during Earth's early period to the modern oxidized crust and mantle has never been captured by geochemical surveys on Earth materials as old as ∼4.0 billion years ago. By combining available trace-elements data of igneous zircons of crustal origin, we show that the Hadean continental crust was significantly more reduced than its modern counterpart and experienced progressive oxidation till ∼3.6 billions years ago. We suggest that the increase in the oxidation state of the Hadean continental crust is related to the progressive decline in the intensity of chondritic addition during the late veneer. Inputs of carbon- and hydrogen-rich chondritic materials during the formation of Hadean granitic crust must have favored strongly reduced magmatism. The conjunction of cold, wet and reduced granitic magmatism during the Hadean implies the production of methane-rich fluids, in addition to the CO- and H2-rich volcanic species produced by degassing of hot reduced basaltic melts as modified by delivered materials during the late veneer. When the late veneer events ended, magma produced by normal decompression melting of the mantle imparted more oxidizing conditions to erupted lavas and the related crust, emitting CO2- and H2O-rich gases. Our model suggests that the Hadean continental crust was possibly much weaker than present-day, facilitating intrusion of underplating magma and thus allowing faster crustal growth in the early Earth.

Published
2014
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45. Local redox buffering by carbon at low pressures and the formation of moissanite – natural SiC

Author

Fabrice Gaillard, Andrei A. Shiryaev, Institute of Physical Chemistry and Electrochemistry RAS, Institute of Geology of Ore Deposits, Russian Academy of Sciences [Moscow] (RAS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
mantle redox state, [SDE.MCG]Environmental Sciences/Global Changes, Mineralogy, engineering.material, Redox, Mantle (geology), Silicate, chemistry.chemical_compound, moissanite, chemistry, silicon carbide, Geochemistry and Petrology, Chemical physics, carboreduction, thermodynamic modeling, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Silicon carbide, engineering, Kimberlite, Moissanite, Geology
Abstract

International audience; Grains of natural SiC, moissanite, are encountered in various geological settings. According to thermodynamic calculations and high-pressure experiments, SiC formation requires very reducing conditions, approx. 6-10 orders of magnitude in fO2 more reducing than the present-day mantle redox state. SiC occurrences have motivated several studies but the required extremely reducing conditions remain a major inconsistency that has not been solved. It is shown here that such reducing conditions can be achieved during the ultimate steps of ascent of carbon-saturated melts, when pressure is lower than 100 bars. At these conditions, the redox buffering by carbon can impose fO2 similar to IW-6. Conditions favorable to SiC growth can therefore be reached around carbonaceous grains during the shallow emplacement of silicate melts or kimberlites and do not necessarily imply extremely localized oxygen-depleted regions in the mantle. Such reduced conditions can also explain the presence of elemental Si and iron-carbide inclusions in association with moissanite grains.

Published
2014
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46. Experimental assessment of the relationships between electrical resistivity, crustal melting and strain localization beneath the Himalayan–Tibetan Belt

Author

Fabrice Gaillard, Bruno Scaillet, Nicole Le Breton, Rémi Champallier, Laurent Arbaret, and Leila Hashim

Subjects
geography, Plateau, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Muscovite, Partial melting, Crust, Geophysics, Atmospheric temperature range, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Viscosity, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Magnetotellurics, Electrical resistivity and conductivity, Earth and Planetary Sciences (miscellaneous), engineering, Petrology, Geology, 0105 earth and related environmental sciences
Abstract

Seismic and magnetotelluric field campaigns carried out across the Himalaya and the Tibetan Plateau show mid-crustal low resistivity and low velocity zones. Interpretation of these anomalous observations, either saline fluids or partial melts, is still largely debated partly because experimental data simulating crustal melting under relevant pressure, temperature and water content conditions have not been provided. We report laboratory measurements constraining the resistivity as a function of temperature and the viscosity at 800 °C of natural metapelite during partial melting. Dehydration-melting of muscovite is simulated using a Paterson press at 300 MPa in the temperature range 600–850 °C. Electrical resistivity has been measured from the solid state ( 800 °C) and viscosity has been determined at 800 °C. Our results together with recent experimental constraints on seismic properties of partially molten rocks strongly suggest that the electrical and seismic anomalies measured underneath the Himalayan–Tibetan collisional orogen are best explained by partially molten rocks or local accumulation of pure melt bodies. This is also remarkably corroborated by the temperature–depth conditions of crustal partial melting and melt ponding expected from petrological surveys in the Himalayan range. However, our data suggest much higher melt fraction than previously thought and this implies regions in the middle crust having viscosities several orders of magnitude lower than previously assumed. High degree partial melting in the middle crust of the Himalayan–Tibetan orogenic system suggests revision of conceptual models on the development of mountain belts or that geophysical models addressing electrical resistivity at depth must be re-evaluated.

Published
2013
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47. 17 O NMR evidence of free ionic clusters Mn+ CO3 2− in silicate glasses: Precursors for carbonate-silicate liquids immiscibility

Author

Yann Morizet, Fabrice Gaillard, Pierre Florian, Michael Paris, 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), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), and Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Inorganic chemistry, Molecular configuration, 010502 geochemistry & geophysics, 01 natural sciences, Silicate, chemistry.chemical_compound, Geophysics, Polymerization, chemistry, 13. Climate action, Geochemistry and Petrology, Carbon dioxide, Carbonate, Molecule, Silicate glass, Dissolution, 0105 earth and related environmental sciences, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; Carbon dioxide is a ubiquitous component of low-silica melts such as kimberlites or melilitites. It is currently assumed that CO2 molecules dissolving in low-silica melts as carbonate groups (CO32−) induce a strong polymerization of the silicate network; however, the exact molecular configuration of this dissolution mechanism is still debated.Using 17O MAS NMR spectroscopy, we have investigated the carbonate molecular environment in a series of synthesized low-silica (31–41 wt% SiO2), CO2-bearing (from 2.9 to 13.2 wt% CO2) silicate glasses analogous to melilitites and kimberlites. With the selective {13C}-, {27Al}-, and {29Si}-17O J HMQC NMR method, we show that CO2 dissolved in the studied low-silica glasses is totally disconnected from the silicate network, forming free ionic clusters (FIC) Mn+ CO32− with Mn+, a charge compensating cation.The Mn+ CO32− FIC are considered as precursors to immiscibility in between carbonate and silicate liquids. Observed in all studied compositions, we suggest that this immiscibility can be produced from moderately to strongly depolymerized silicate melt compositions.

Published
2017
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48. Towards the reconciliation of viscosity change and CO 2 -induced polymerization in silicate melts

Author

Sandra Ory, Ida Di Carlo, Yann Morizet, David Sifré, Michael Paris, Fabrice Gaillard, 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), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, CO2 effect on silicate melt viscosity, Cationic polymerization, Mineralogy, Geology, Degree of polymerization, 010502 geochemistry & geophysics, 01 natural sciences, CO2 dissolution mechanism, Silicate, chemistry.chemical_compound, Viscosity, Low silica melt polymerization, chemistry, Polymerization, Chemical engineering, 13. Climate action, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Carbonate, Glass transition, Dissolution, 0105 earth and related environmental sciences
Abstract

International audience; Deep mantle melts contain massive amounts of CO2 but three critical issues related to the effect of CO2 on molecular structure and physical properties of magmatic melts remain poorly constrained: 1) there is no exact picture of CO2 dissolution mechanism in silicate melt, 2) the silicate melt polymerization upon CO2 dissolution has not been reliably quantified and 3) the effect of CO2 on silicate melt viscosity has never been measured adequately.We synthesized a series of 17O and 29Si-enriched CO2-bearing melilitite (SiO2 ~ 35 wt%) silicate glasses at high temperature and pressure. Using NMR spectroscopy, we have interrogated both anionic and cationic networks for quantifying the change in the degree of polymerization associated to CO2 incorporation in the melt. Increasing CO2 content induces a strong increase in the degree of polymerization. CO2 dissolution follows a complex mechanism involving the formation of Free Ionic Carbonate (FIC) Ca2 +·CO32– species. This carbonate subnetwork is the precursor to the immiscibility process between a carbonate liquid and a silicate liquid.Glass transition temperature (Tg) measurements show that increasing CO2 content induces a decrease in Tg implying a decrease in viscosity for the studied low silica melt composition. This result appears in complete contradiction with the melt polymerization induced by CO2 as quantified by NMR. We propose a model that reconciles both aspects. CO2 induces silicate subnetwork polymerization resulting in a viscosity increase but it also induces a competing effect by forming a carbonate subnetwork having a low viscosity. The overall result appears dominated by the carbonate subnetwork resulting in a slight decrease in melt viscosity in agreement with existing studies.

Published
2017
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49. The effect of Mg concentration in silicate glasses on CO 2 solubility and solution mechanism: Implication for natural magmatic systems

Author

Fabrice Gaillard, Yann Morizet, David Sifré, Michael Paris, Ida Di Carlo, 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), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
010504 meteorology & atmospheric sciences, Chemistry, Analytical chemistry, Mineralogy, Ionic bonding, Nuclear magnetic resonance spectroscopy, 010502 geochemistry & geophysics, 01 natural sciences, symbols.namesake, CO2 content, 13. Climate action, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, symbols, Molecule, Solubility, Raman spectroscopy, Dissolution, Stoichiometry, 0105 earth and related environmental sciences
Abstract

International audience; Following an experimental approach conducted between 0.5 and 1.5 GPa, we investigated the change in CO2 solubility as a function of the XMg (MgO/(MgO+CaO)) for a range of silicate glasses. The synthesised CO2-bearing glasses have XMg up to 0.72, stoichiometric NBO/T (degree of polymerization) up to 2.6 corresponding to highly depolymerized compositions analogues to kimberlites. Several samples were synthesised with 17O enrichment to investigate the CO2 dissolution mechanism via the change in O species environments by NMR spectroscopy.The experimental results show that CO2 solubility increases with NBO/T in agreement with previous works. In addition, increasing XMg strongly decreases CO2 solubility: from 18 to 7 wt.% CO2 as XMg ranges from 0 to 0.6 (1.5 GPa and NBO/T ~ 2).17O NMR results demonstrate that CO2 molecules dissolve as CO3^2- groups showing a signal at +146 ppm for which the intensity is linearly correlated to the wt.% CO2 determined by Raman. The analysis of the oxygen environments as a function of CO2 content for MgO^NBO (+62 ppm) and CaO^NBO (+103 ppm) show that CO2 dissolves preferentially in the vicinity of Ca2+ atoms. The difference in CO2 solubility is explained by the ability for Mg2+ cations to act as a weak network former and to be present in four-fold coordination or by the stronger affinity of CO2 molecules for Ca2+ rather than for Mg2+. We show that the CO2 solubility is negatively correlated to the melt ionic field strength which reflects the variation in the affinity of CO2 molecules for one cation or another.Strongly depolymerized mantle melts, such as kimberlites, melilitites, nephelinites and basanites will exhibit lower CO2 solubility than currently assumed due to their high MgO content which must imply degassing at greater depth, potentially in the sub-lithospheric mantle.

Published
2017
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50. Giant magmatic water reservoirs at mid-crustal depth inferred from electrical conductivity and the growth of the continental crust

Author

Jon D Blundy, Duncan Muir, Fabrice Gaillard, Martyn Unsworth, Mickael Laumonier, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Bayerisches Geoinstitut (BGI), Universität Bayreuth, Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), School of Earth and Ocean Sciences [Cardiff], Cardiff University, School of Earth Sciences [Bristol], University of Bristol [Bristol], Department of Earth and Atmospheric Sciences [Edmonton], University of Alberta, ANR-10-BLAN-0621,ELECTROLITH,Le devenir des volatils et les conductivités électriques du manteau connectés par les carbonatites(2010), European Project: 279790,EC:FP7:ERC,ERC-2011-StG_20101014,ELECTROLITH(2011), European Project: 247162,EC:FP7:ERC,ERC-2009-AdG,CRITMAG(2010), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], water, Geochemistry, 010502 geochemistry & geophysics, 01 natural sciences, Magmatic water, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, Volcanic arc, Subduction, electrical conductivity, andesite, Continental crust, Andesite, Crust, 15. Life on land, arc magmas, Geophysics, Volcano, Space and Planetary Science, Magma, continental crust growth, Geology
Abstract

The formation of the continental crust at subduction zones involves the differentiation of hydrous mantle-derived magmas through a combination of crystallization and crustal melting. However, understanding the mechanisms by which differentiation occurs at depth is hampered by the inaccessibility of the deep crust in active continental arcs. Here we report new high-pressure electrical conductivity and petrological experiments on hydrated andesitic melt from Uturuncu volcano on the Bolivian Altiplano. By applying our results to regional magnetotelluric data, we show that giant conductive anomalies at mid-crustal levels in several arcs are characterized by relatively low amounts of intergranular andesitic partial melts with unusually high dissolved water contents (≥8 wt.% H2O). Below Uturuncu, the Altiplano-Puna Magma Body (APMB) displays an electrical conductivity that requires high water content (up to 10 wt.%) dissolved in the melt based on crystal-liquid equilibria and melt H2O solubility experiments. Such a super-hydrous andesitic melt must constitute about 10% of the APMB, the remaining 90% being a combination of magmatic cumulates and older crustal rocks. The crustal ponding level of these andesites at around 6 kbar pressure implies that on ascent through the crust hydrous magmas reach their water saturation pressure in the mid-crust, resulting in decompression-induced crystallization that increases magma viscosity and in turn leads to preferential stalling and differentiation. Similar high conductivity features are observed beneath the Cascades volcanic arc and Taupo Volcanic Zone. This suggests that large amounts of water in super-hydrous andesitic magmas could be a common feature of active continental arcs and may illustrate a key step in the structure and growth of the continental crust. One Sentence Summary: Geophysical, laboratory conductivity and petrological experiments reveal that deep electrical conductivity anomalies beneath the Central Andes, Cascades and Taupo Volcanic Zone image the ponding of super-hydrous andesitic melts which contributes to the growth of continental crust.

Published
2017
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