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Terre profonde: composition, structure, dynamique

Terre profonde: composition, structure, dynamique Institut de Minéralogie et de Physique des Milieux Condensés Institut de Physique du Globe de Paris. Composition chimique du noyau terrestre Anisotropie sismique de la graine

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Terre profonde: composition, structure, dynamique

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  1. Terre profonde: composition, structure, dynamique Institut de Minéralogie et de Physique des Milieux Condensés Institut de Physique du Globe de Paris Composition chimique du noyau terrestre Anisotropie sismique de la graine Diagrammes de phases et propriétés physiques des alliages de fer à l’état liquide G. Fiquet, J. Badro, A.L. Auzende, D. Antonangeli, J. Siebert

  2. Sample thermal emission Intensity Wavelength YAG, YLF or CO2 infrared laser

  3. Synchrotron sources…

  4. Sound velocities in iron and core properties Fiquet G., Badro J., Guyot F. et al., Science, 291, 468, 2001. Badro J., Fiquet, G., Guyot F. et al., EPSL, 254, 1-2, 233, 2007 Core with 8 wt% light elements

  5. P = 112 GPa P = 22 GPa For P=22 GPa VP{50°}  VP{90°} For P=112 GPa VP{50°} > VP{90°} Anisotropy of longitudinal acoustic velocities in iron aggregate at high pressure ANISOTROPY 4-5% Antonangeli, D., Fiquet G., Badro, J. et al., EPSL 225, 243 (2004)

  6. ● Elastic tensor of cobalt at high pressure (as a proxy for iron) Antonangeli et al., Phys. Rev. Lett., 2004 Antonangeli et al., Phys. Rev. B, 2005 Merkel et al., J. Appl. Phys., 2006 ●Elastic anisotropic properties of iron (sound velocities, anisotropy, c/a ratio at high-pressure and high-temperature…) Antonangeli et al., EPSL 2004 Antonangeli et al., GRL, 2006 Fiquet et al., J. Geophys. Res., in preparation ●Elastic properties and phase diagram of molten alloys (Fe-FeS, Fe-Si-S, Fe-FeO) Sanloup et al., Geophys. Res. Lett., 27, 811, 2000 Sanloup et al., Geophys. Res. Lett., 31, L07604, 2004 Morard et al., High Pressure Research, in press

  7. (Mg0.90 Fe0.10)SiO3 X-ray Emission Spectra of Perovskite Badro et al. Science (2004) High-pressure spin-pairing transition in magnesiowuestite at 65-70 GPa Badro J., Fiquet G., Guyot F. et al. Science, 300, 789

  8. [1] Transition HS/BS [2] Transition pv/postpv Fp Pv Partage (Fe,Mg) entre la pérovskite et le ferropériclase Pérovskite Mg et Ferropériclase = phases dominantes du manteau inférieur Partitioning coefficient K (pv/mw) P = 72 GPa Caractérisation par imagerie, diffraction électronique et analyse chimique Résultat: Fortes variations du partage du fer dans le manteau inférieur Conséquences géodynamiques? Auzende et al., EPSL, 2008

  9. LS HS Thermal Conductivity (radiative term)

  10. BS PREM 1000 40 Cold slab A ak135 60 Hot slab 1500 Pressure (GPa) 80 Depth (km) 2000 100 2500 120 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1  -  PREM The fate of subducted basaltic crust in the Earth's lower mantle ● Perrillat J.P., Ricolleau A., Daniel I., Fiquet G., Mezouar M., Guignot N., Cardon H. (2006) Phase transformations of subducted basaltic crust in the upmost lower mantle. Physics of the Earth and Planetary Interiors 157, 139–149 High-pressure high-temperature in situ X-ray diffraction on MORB samples (ESRF, Grenoble) combined with analytical TEM study of recovered samples Ricolleau et al., Amer. Mineral., 2008

  11. 200 nm IR laser CED : Outil pétrologique et géochimique pour la Terre profonde FIB (focused ion beam) : préparation d’échantillons MET-A : caractérisation minéralogique et chimique (éléments majeurs, état d’oxydation) Fp Pv STXM: caractérisation de l’état d’oxydation des éléments (Fe2+/Fe3+)- ALS, SLS, Soleil 708eV Pv NanoSIMS : caractérisation chimique (éléments traces) MNHN, LLNL MgO ____ 1 μm Olivine

  12. St CF Ca-pv Mg-pv Height ~ 5µm St Length ~ 20µm Thickness ~ 100nm MORB sample recovered from 55 GPa

  13. Phases de HP Partage entre liquide et solide à haute pression Le manteau profond a connu des épisodes de fusion Liquide La cristallisation de l’océan magmatique = stratification du manteau terrestre Océan magmatique Réconciliation modèles géophysiques & modèles géochimiques Kellogg et al., 1999

  14. Fusion à la frontière noyau-manteau ULVZ : fusion partielle en base de manteau Fractionnement élémentaire -> modifications U/Pb, Sm/Nd… Comparaison avec signature des OIB Lay et al, 1998

  15. Influence of changes in the electronic state on chemical and physical properties of lower mantle minerals. • Study of critical transport properties of minerals at high-pressure and temperature (thermal conductivity, diffusivity) - C2C RTN Marie Curie post-doctoral position open) • Elastic properties of Earth materials, phase diagrams (Al and Fe enriched perovskite compounds, iron elastic tensor at high pressure and high temperature) • Physical properties and phase relations of slab-related compositions (MORB, harzburgite, sediments) • Core mantle boundary (partial melting in the lowermost mantle), Earth differentiation (magma ocean, core segregation) • Flux of volatiles released into the mantle (carbon deep cycle, nitrogen)

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