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2. In situ X-ray diffraction of silicate liquids and glasses under dynamic and static compression to megabar pressures

Author

Morard, Guillaume, Hernandez, Jean-Alexis, Guarguaglini, Marco, Bolis, Riccardo, Benuzzi-Mounaix, Alessandra, Vinci, Tommaso, Fiquet, Guillaume, Baron, Marzena A., Shim, Sang Heon, Ko, Byeongkwan, Gleason, Arianna E., Mao, Wendy L., Alonso-Mori, Roberto, Lee, Hae Ja, Nagler, Bob, Galtier, Eric, Sokaras, Dimosthenis, Glenzer, Siegfried H., Andrault, Denis, Garbarino, Gaston, Mezouar, Mohamed, Schuster, Anja K., and Ravasio, Alessandra

Published
2020

21. Solid-liquid iron partitioning in Earth's deep mantle

Author

Andrault, Denis, Petitgirard, Sylvain, Nigro, Giacomo Lo, Devidal, Jean-Luc, Veronesi, Giulia, Garbarino, Gaston, and Mezouar, Mohamed

Subjects
Observations, Environmental aspects, Volcanic hotspots -- Environmental aspects -- Observations, Mantle (Geology) -- Observations, Earth -- Mantle
Abstract

Melting processes in the deep mantle have important implications for the origin of the deep-derived plumes believed to feed hotspot volcanoes such as those in Hawaii (1). They also provide [...]

Published
2012

24. Structural characterization of natural U[O.sub.2] at pressures up to 82 GPa and temperatures up to 2200 K

Author

Greaux, Steeve, Gautron, Laurent, Andrault, Denis, Bolfan-Casanova, Nathalie, Guignot, Nicolas, and Haines, Julien

Subjects
Uranium -- Structure, Uranium -- Thermal properties, Crystals -- Structure, Crystals -- Analysis, Earth sciences research, Earth sciences
Abstract

Uranium is one of the main heat sources in the Earth, as about 25% of the total heat is produced by the radioactive decay of U. The location of U in the deep mantle is then essential for a better understanding of the geodynamics and thermal behavior of the Earth. For the first time, the crystal structure of natural simple dioxide U[O.sub.2] uraninite has been studied by X-ray diffraction with synchrotron radiation (ESRF, Grenoble, France), in situ in a laser-heated diamond-anvil cell at pressures and temperatures relevant to the deep Earth's mantle. Fluorite-type U[O.sub.2] displays a new sequence of phase transitions at high P and T, with a cubic modified fluorite Pa[bar.3] observed at 18 GPa, and an orthorhombic Pbca structure from 33 GPa up to 82 GPa. Using a second-order Birch-Murnaghan equation of state, we calculated room-pressure bulk modulus [K.sub.0] = 166(7) GPa with pressure derivative [K'.sub.0] = 4.0 for the Pa[bar.3] structure, and [K.sub.0] = 225(8) GPa with [K'.sub.0] = 4 for the Pbca structure. The expected Pnma cotunnite structure was not observed but is not excluded at pressures higher than 82 GPa. Since U[O.sub.2] displays a Pbca structure stable up to 82 GPa and presents a density much higher than the average density of the surrounding mantle, U[O.sub.2] could be a host of U in the deep lower mantle. Keywords: Heat sources, uranium oxide, X-ray diffraction, crystal structure, deep mantle

Published
2008

25. Equation of state of stishovite to lower mantle pressures

Author

Andrault, Denis, Angel, Ross J., Mosenfelder, Jed L., and Le Bihan, Tristan

Subjects
Equations of state -- Analysis, Phase transformations (Statistical physics) -- Models, Mineralogical chemistry -- Measurement, Earth sciences
Abstract

We performed new diffraction experiments to clarify the equation of state (EoS) of stishovite after we suspected systematic errors in previous experimental reports. Using diamond anvil cells, we repeated both single-crystal X-ray diffraction measurements under hydrostatic conditions and powder diffraction measurements using the laser-annealing technique and NaCl pressure medium. The major improvement is the increase in precision of the pressure determination using the quartz and NaCl equations of state. Using both sets of data, the stishovite bulk moduli were refined to [K.sub.0] = 309.9(1.1) GPa and [K'.sub.0] = 4.59(0.23). We also reinvestigated the mechanism of the phase transformation to the Ca[Cl.sub.2]-structured polymorph of Si[O.sub.2] at about 60 GPa. We confirm no volume discontinuity at the transition pressure, but the Ca[Cl.sub.2] form appears slightly more compressible than the rutile-structured form of Si[O.sub.2]. This change in compression behavior is used for quantitative analyses of the spontaneous strains of the pressure-induced phase transition.

Published
2003

26. Structural refinements of magnesite at very high pressure

Author

Fiquet, Guillaume, Guyot, Francois, Kunz, Martin, Matas, Jan, Andrault, Denis, and Hanfland, Michael

Subjects
Mineralogical research -- Analysis, Magnesite -- Analysis, Crystals -- Structure, Earth sciences
Abstract

Unit-cell parameters of magnesite were measured between ambient pressure and 80 GPa using angle dispersive powder X-ray diffraction. The isothermal bulk modulus determined from a third order Birch Murnaghan equation of state is [K.sub.T] = 108(3) GPa with [K'.sub.T] = 5.0(2), and [V.sub.0] = 279.2(2) [[Angstrom].sup.3], in agreement with previously reported values. Combining this result with previous measurements, we show that magnesite with R[bar]3c structure is stable compared to the assemblage periclase + carbon dioxide at pressures and temperatures corresponding to the core-mantle boundary. Crystal structure refinements have also been carried out up to 80 GPa. The main structural change is a strong compression of the Mg[O.sub.6] octahedra with increasing pressure, largely reflected in the anisotropic compression of the c axis. This compression, however, tends to level off at around 50-60 GPa. On the other hand, the C[O.sub.3] groups do not remain invariant since they undergo first a slight expansion and then a compression above the same threshold pressure of 60 GPa above which Mg-O bonds cannot compress further. Thus, in this structure-type, the energy gain due to a drastic volume reduction of the Mg[O.sub.6] octahedron compensates in a given pressure range for the energy cost of the small expansion of the C[O.sub.3] carbonate unit.

Published
2002

30. Structure analysis and stability field of (Beta)-iron at high P and T

Author

Andrault, Denis, Fiquet, Guillaume, Charpin, Thomas, and Le Bihan, Tristan

Subjects
Iron -- Spectra, Materials -- Thermal properties, Materials at high temperatures -- Research, Materials at high pressures -- Research, Matter -- Properties, Earth sciences
Abstract

New synchrotron X-ray diffraction data confirm our previous report of the transformation of the hexagonal close-packed (hcp) phase of iron to the Pbcm orthorhombic lattice ((beta)-iron) at high P and T. The volume differences between the (epsilon) and (beta), and the (beta) and (gamma) polymorphs are determined as 1.4 and 1.8%, respectively, indicating positive Clapeyron slopes between these polymorphs in the P-T phase diagram. All three polymorphs have a similar bulk modulus between 30 and 60 GPa. The Pbcm-polymorph can be observed in a metastable state as quenched from high T at high P and also at high T for P lower than 35 GPa where (beta)-iron is not a stable phase. Metastability is possible because the gliding of the same dense atomic layers is involved in both T-induced (epsilon)-hcp to (gamma)-fcc and (epsilon)-hcp to (beta)-Pbcm transformations. These observations explain why a controversy exists on the structure and P-T stability field of (beta)-iron. From our set of experiments, we estimate that Pbcm-iron is stable above 35 GPa and 1500 K, and that the ((gamma),(beta) liquid-iron) triple point is located at about 55 GPa and 2400 K.

Published
2000

31. The influence of the Earth’s early mantle viscosity on its cooling dynamics

Author

Monteux, Julien, Andrault, Denis, Guitreau, Martin, Samuel, H., Demouchy, Sylvie, 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), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Jouhannel, Sylvaine, 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), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)

Subjects
[SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, [SDU.STU.PE] Sciences of the Universe [physics]/Earth Sciences/Petrography, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

34. Comment on: Melting behavior of SiO2 up to 120 GPa (Andrault et al. 2020).

Author

Andrault, Denis, Pison, L., Morard, G., Garbarino, G., Mezouar, M., Bouhifd, M. A., and Kawamoto, T.

Subjects
DIAMOND anvil cell, MELTING
Abstract

The additional work we have done using our new laser heating in the diamond anvil cell system since the publication of Andrault et al. (Phys Chem Mineral 47(2), 2020) leads us to the conclusion that there was a systematic bias in the determination of temperature. First, the temperature of the W-lamp used for the calibration of the optical system was overestimated by ~ 22 K at 2273 K. Then, we made the assumption that hot SiO2 was a grey-body (constant emissivity ε(λ)), while the available measurements suggest instead that ε(λ) of SiO2 is similar to that of tungsten. Applying these two corrections lowers the SiO2 melting temperatures significantly. In LMV, we performed a new experimental determination of the SiO2 melting temperature, at 5000 (200) K and ~ 70 (4) GPa, which is well compatible with the amplitude of the correction proposed. The reevaluation of the melting temperature profile does not affect largely the interpretations or the main conclusions presented in Andrault et al. (Phys Chem Mineral 47(2), 2020). Within the stability field of stishovite, the melting curve still presents a relatively sharp change of slope at P–T recalculated as ~ 40 GPa and ~ 4800 K. It is related to a change of the melt structure. At higher pressures, the melting curve is almost flat up to the subsolidus transition from stishovite to the CaCl2-form around 85 GPa, where the slope of the melting curve increases again up to ~ 120 GPa. We present corrected figures and tables of the original publication. [ABSTRACT FROM AUTHOR]

Published
2022
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36. Low hydrogen contents in the cores of terrestrial planets

Author

Clesi, Vincent, Bouhifd, Mohamed Ali, Bolfan-casanova, Nathalie, Manthilake, Geeth, Schiavi, Federica, Raepsaet, Caroline, Bureau, Helene, Khodja, Hicham, Andrault, Denis, 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), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - 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-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), 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), CNRS-INSU (Programme National de Planétologie), ANR-13-BS06-0008,OxyDeep,Etat redox de la Terre profonde au cours de son evolution(2013), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-11-JS56-0015,HYDEEP,Cycle Profond de l'Hydrogène dans la Terre(2011), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), 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), 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), and 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)

Subjects
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [CHIM.MATE]Chemical Sciences/Material chemistry
Abstract

Co-auteur étranger; International audience; Hydrogen has been thought to be an important light element in Earth's core due to possible siderophile behavior during core-mantle segregation. We reproduced planetary differentiation conditions using hydrogen contents of 450 to 1500 parts per million (ppm) in the silicate phase, pressures of 5 to 20 GPa, oxygen fugacity varying within IW-3.7 and IW-0.2 (0.2 to 3.7 log units lower than iron-wüstite buffer), and Fe alloys typical of planetary cores. We report hydrogen metal-silicate partition coefficients of ~2 × 10$^{−1}$ , up to two orders of magnitude lower than reported previously , and indicative of lithophile behavior. Our results imply H contents of ~60 ppm in the Earth and Martian cores. A simple water budget suggests that 90% of the water initially present in planetary building blocks was lost during planetary accretion. The retained water segregated preferentially into planetary mantles.

Published
2018
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37. 182W evidence for core-mantle interaction in the source of mantle plumes

Author

Rizo, Hanika, Andrault, Denis, Bennett, Neil, Humayun, Munir, Brandon, Alan, Vlastelic, Ivan, Moine, B., Poirier, Andre, Bouhifd, Mohamed Ali, Murphy, David, Rizo, Hanika, Andrault, Denis, Bennett, Neil, Humayun, Munir, Brandon, Alan, Vlastelic, Ivan, Moine, B., Poirier, Andre, Bouhifd, Mohamed Ali, and Murphy, David

Abstract

Tungsten isotopes are the ideal tracers of core-mantle chemical interaction. Given that W is moderately siderophile, it preferentially partitioned into the Earth’s core during its segregation, leaving the mantle depleted in this element. In contrast, Hf is lithophile, and its short-lived radioactive isotope 182Hf decayed entirely to 182W in the mantle after metal-silicate segregation. Therefore, the 182W isotopic composition of the Earth’s mantle and its core are expected to differ by about 200 ppm. Here, we report new high precision W isotope data for mantle-derived rock samples from the Paleoarchean Pilbara Craton, and the Réunion Island and the Kerguelen Archipelago hotspots. Together with other available data, they reveal a temporal shift in the 182W isotopic composition of the mantle that is best explained by core-mantle chemical interaction. Core-mantle exchange might be facilitated by diffusive isotope exchange at the core-mantle boundary, or the exsolution of W-rich, Si-Mg-Fe oxides from the core into the mantle. Tungsten-182 isotope compositions of mantle-derived magmas are similar from 4.3 to 2.7 Ga and decrease afterwards. This change could be related to the onset of the crystallisation of the inner core or to the initiation of post-Archean deep slab subduction that more efficiently mixed the mantle.

Published
2019

40. Oxygen K-edge fine structures of water by x-ray Raman scattering spectroscopy under pressure conditions.

Author

Fukui, Hiroshi, Huotari, Simo, Andrault, Denis, and Kawamoto, Tatsuhiko

Subjects
OXYGEN, WATER, HIGH pressure (Science), LOW pressure (Science), PRESSURE, RAMAN effect, RAMAN spectroscopy, HYDROGEN bonding
Abstract

Fine structure of the oxygen K edge was investigated for water at ambient pressure, 0.16, 0.21, 0.27, 0.47, and 0.60 GPa using x-ray Raman scattering spectroscopy (XRS). Similarity in near-edge structures at 0.16 and 0.60 GPa suggests little difference in the electronic state of oxygen in the low-pressure and high-pressure forms of water. Yet, we observed significant variation of preedge structure of the XRS spectra with compression. The intensity of the preedge peak at 535.7 eV has a minimal value at around 0.3 GPa, indicating that the number of hydrogen bonding increases first and then decreases as a function of pressure. [ABSTRACT FROM AUTHOR]

Published
2007
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41. Effect of melt content and the melt texture on sound wave velocity and electrical conductivity

Author

Freitas, D., Manthilake, Geeth, Chantel, Julien, Bouhifd, Mohamed Ali, Andrault, Denis, freitas, Damien, 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), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), and Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy, [SDU.STU.MI] Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; The geophysical observations of elevated electrical conductivity (EC) and reduced seismic wave velocity (SWV) have long been discussed in conjunctions with partial melting in the Earth's asthenosphere. Alternative mechanisms based on solid state processes, such as anelastic relaxation and hydrogen diffusion in mantle minerals have also been proposed. However, the recent finding of young alkali basalt (< 10 Ma) on the 135 million-year-old Pacific-plate provides strong physical evidences for the partial melting at the top of the asthenosphere. Various experimental techniques have been used to constrain the melt fraction in the asthenosphere low velocity zone (LVZ) reported at depth of 70-220 km. Geochemical and petrological constrains suggest low degree melting (less than 1 %) in the asthenosphere, while laboratory based EC and SWV measurements suggest melt fractions ranging from 0.1 to 10 %. Moreover, the comparison between geophysical observations and laboratory measurements of EC and SWV also yields contradicting estimations of the melt fraction, highlighting potential disagreements between EC and SWV techniques. In this study we aimed at investigating the effect of melt fraction and the melt texture, key parameters governing the magnitude and the style of seismic velocity and electrical conductivity variations. We performed simultaneous sound wave velocity and electrical conductivity measurements on mixtures of San Carlos olivine and natural mid oceanic ridge basalt (MORB) at 2.5 GPa and up to 1650 K. This critical improvement enables us to understand how seismic and electrical measurments responses to melt volume fractions and the evolution of melt interconnectivity with time in a partially molten sample. With our results, we were able to determine the potential limitations associated with laboratory based electrical conductivity and seismic wave velocity measurements for estimation of the melt fraction. Overall, the seismic velocity measurements appear more appropriate method to determine the melt fraction in a partially molten system. Based on our results, the geophysical anomalies observed in the LVZ of the asthenosphere can be explained with 0.3 to 0.8 vol. % of MORB-like melt.

Published
2017

42. Mesures simultanées de conductivité électrique et de vitesse d'ondes sismiques de matériaux géologiques partiellement fondus à haute pression et haute température : implication pour la fraction de liquide silicaté dans l'asthénosphère

Author

Freitas, D., Manthilake, Geeth, Chantel, Julien, Andrault, Denis, 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), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), 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), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS), and freitas, Damien

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.STU.MI] Sciences of the Universe [physics]/Earth Sciences/Mineralogy, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; Un débat important existe actuellement sur les capacités des systèmes partiellement fondus à augmenter la conductivité électrique et réduire la vitesse des ondes sismiques du matériel géologique, nécessaires pour expliquer la présence de zones d’anomalies géophysiques dans le manteau terrestre (zone de faible vitesse : LVZ de l’asthénosphère entre 70 et 200 Km [1],[2],[3]). De nombreuses hypothèses alternatives ont été proposées et sont basées sur des processus à l’état solide [4] telles la diffusion de l’hydrogène dans la structure cristalline. Ces théories suggèrent une asthénosphère sans fusion partielle. Alors que de fortes évidences physiques confirment la présence de fusion partielle du manteau asthénosphérique, comme la découverte de basaltes alcalins jeunes disposés sur la plaque océanique indienne beaucoup plus ancienne [5], les mesures expérimentales de conductivité électriques et de vitesse des ondes sismiques réalisées en laboratoire sur les systèmes partiellement fondus apportent des estimations antagonistes de la fraction de liquide silicaté impliqué dans l’asthénosphère. De plus, la source du désaccord entre les deux techniques géophysiques (conductivité électrique et vitesse sismique) demeure toujours mal contrainte.Utilisant les nouvelles techniques expérimentales développées sur la presse multi-enclumes au Laboratoire Magmas et Volcans de Clermont-Ferrand, des mesures couplées de conductivité électrique et de vitesse des ondes acoustiques ont été réalisées de façon in situ et simultanée sur le même échantillon. Nous avons alors étudié des systèmes partiellement fondus en utilisant des échantillons composés d’un mélange biphasé d’olivine de San Carlos (standard pétrologique) et d’un basalte de ride médio-océanique hydraté provenant de la ride Est-Pacifique (issu d’un forage) dans des conditions de haute pression : 2.5 GPa et de haute température: jusqu’à 1650 K.

Published
2016

43. Topologically ordered amorphous silica obtained from the collapsed siliceous zeolite, silicalite-1-F: a step toward 'perfect' glasses

Author

Haines, Julien, Levelut, Claire, Isambert, Aude, Hebert, Philippe, Kohara, Shinji, Keen, David A., Hammouda, Tahar, and Andrault, Denis

Subjects
High pressure chemistry -- Analysis, Metallic glasses -- Chemical properties, Metallic glasses -- Optical properties, Silica -- Structure, Silica -- Chemical properties, Zeolites -- Structure, Zeolites -- Chemical properties, Chemistry
Abstract

A dense amorphous form of silica is prepared at high pressure from the highly compressible, siliceous zeolite, silicalite-1-F. This is an example of new topologically ordered, amorphous material with a different intermediate-range structure, a lower entropy with respect to a standard glass and distinct physical and mechanical properties, which has eventually approached an 'ordered' or 'perfect' glass.

Published
2009

44. Cosmochemical fractionation by collisional erosion during the Earth’s accretion

Author

Boujibar, Asmaa, Andrault, Denis, Bolfan-casanova, Nathalie, Bouhifd, Mohamed Ali, Monteux, Julien, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Early in the Solar System's history, energetic collisions of differentiated bodies affected the final composition of the terrestrial planets through partial destruction. Enstatite chondrites (EC) are the best candidates to represent the primordial terrestrial precursors as they present the most similar isotopic compositions to Earth. Here we report that collisional erosion of 415% of the early Earth's mass can reconcile the remaining compositional differences between EC and the Earth. We base our demonstration on experimental melting of an EC composition at pressures between 1 bar and 25 GPa. At low pressures, the first silicate melts are highly enriched in incompatible elements Si, Al and Na, and depleted in Mg. Loss of proto-crusts through impacts raises the Earth's Mg/Si ratio to its present value. To match all major element compositions, our model implies preferential loss of volatile lithophile elements and re-condensation of refractory lithophile elements after the impacts.

Published
2015
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49. Ferric iron and water incorporation in wadsleyite under hydrous and oxidizing conditions: A XANES, Mossbauer, and SIMS study

Author

Bolfan-Casanova, Nathalie, Munoz, Manuel, Mccammon, Catherine, Deloule, Etienne, Ferot, Anais, Demouchy, Sylvie, France, Lyderic, Andrault, Denis, Pascarelli, Sakura, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-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-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Bayerisches Geoinstitut (BGI), Universität Bayreuth, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Chemistry, [SDE.MCG]Environmental Sciences/Global Changes, Inorganic chemistry, ferric iron, Wadsleyite, 010502 geochemistry & geophysics, 01 natural sciences, Redox, XANES, Partition coefficient, Secondary ion mass spectrometry, Metal, Geophysics, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, visual_art, redox, hydroxyl defects, Mössbauer spectroscopy, visual_art.visual_art_medium, Fourier transform infrared spectroscopy, 0105 earth and related environmental sciences
Abstract

International audience; Wadsleyites with various iron contents were synthesized at ~12-14 GPa and 1400 °C under oxidizing and hydrous conditions in coexistence with enstatite. The samples were studied using micro-X-ray absorption near edge structure (XANES) and micro-Mössbauer spectroscopy to determine the ferric iron contents in polyphasic samples and secondary ion mass spectrometry (SIMS) to determine the water concentrations. XANES and Mössbauer analyses show that ferric iron content increases with increasing total iron content, and reaches a maximum of ~30% Fe3+/Fetotal. Two XANES results were cross-checked by Mössbauer analysis and both methods are in reasonable agreement. The use of Fourier transform infrared spectroscopy reveals a new protonation scheme in wadsleyite, with a significant proportion of protons associated with the high-frequency band at 3611 cm−1 and a new band located at 3500 cm−1. The intensity of these two bands is higher for Fe3+-rich wadsleyite. SIMS analyses show that water contents in wadsleyite vary from 4500 to 9400 ppm H2O by weight. Pyroxene water contents range from 790 to 1600 ppm wt H2O. The concentration of water in both phases decreases with increasing iron content. The partition coefficient of water between wadsleyite and pyroxene varies between 5 and 9 and increases with increasing Fe-number of wadsleyite [i.e., XFe/(XFe + XMg) × 100 ratio]. The divalent cation concentrations (i.e., Mg2+ + Fe2+), the Si as well as the H content in wadsleyite decrease with increasing Fe3+ content, indicating an incorporation mechanism via substitution into the metal (Me = Mg2+ and Fe2+) and Si sites with a ratio of 5/3 for (Fe3++H+):Me and of 5/1 for (Fe3++H+):Si, similarly as in the dry system. Thus, coupled substitution of Fe3+ and H+ does not affect the incorporation mechanism of Fe3+, but does affect the location of H+, which is partly incorporated at tetrahedral edges forming [FeSi′-(OH)o*]X neutral defects substituting for Si. In this model 25% of the ferric iron occupies the tetrahedral sites.

Published
2012
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