Modeling solidification, phase separation and convection for magma oceansle - Charles-Edouard Boukaré

IMPMC - UPMC, 4, Place Jussieu - 75005 Paris. Tour 23 - Barre 22-23 - 4e étage, salle 401
Mardi 30 mai 2017 à 13 h 30
Charles-Edouard Boukaré - Brown University, Providence, Rhode Island, USA
Abstract
Since the earliest study of the Apollo lunar samples, the magma ocean hypothesis has received increasing consideration for explaining the early evolution of terrestrial planets. Giant impacts seem to be able to melt significantly large planets at the end of their accretion. The evolution of the resulting magma ocean would set the initial conditions (thermal and compositional structure) for subsequent long-term solid-state planet dynamics. However, magma ocean dynamics remains poorly understood.
The major challenge relies on understanding interactions between the physical properties of materials (e.g., viscosity (liquid or solid state), chemical buoyancy...) and the complex dynamics of a multiphase convecting system. Such complexities might be neglected in cases where liquidus/adiabat interactions and density stratification leads to stable situations. However, interesting possibilities arise when exploring magma ocean dynamics in other regime. In the case of the Earth, recent studies have shown that the liquidus might intersect the adiabat at mid-mantle depth and/or that solids might be buoyant at deep mantle conditions. These results require the consideration of more sophisticated scenarios. For instance, how does bottom-up crystallization look with buoyant crystals?
My talk will be divided into two parts. I will first focus on the petrology of a crystallizing system at deep mantle conditions. Then, I will present a numerical model of multiphase convection which can be used to investigate the impact of the petrology on the multiphase dynamic.
We build a solid-liquid thermodynamic database for silicates in the MgO-FeO-SiO2 system from 20 GPa to 140 GPa [Boukaré et al., 2015, JGR]. We compute the ternary phase diagram in the MgO-FeO-SiO2$_2$ system as a function of temperature and pressure. This self-consistent approach allows us to predict crystallization sequences at deep mantle conditions. We confirm that the melt is lighter than the solid of same composition for all mantle conditions but at thermodynamic equilibrium, the iron-rich liquid is denser than the solid in the deep mantle.
To understand this complex dynamics due to potential density cross-over between melt and solids, we develop a multiphase numerical code that can handle simultaneously phase change, convection in each phase and in the slurry, as well as the compaction or decompaction of the two phases [Boukaré et al., 2017, G3, in review]. Although our code can only run in a limited parameter range (Rayleigh number, viscosity contrast between phases, Prandlt number), it provides a rich dynamics that illustrates what could have happened. For a given liquidus/adiabat configuration, we explore magma ocean scenarios by varying the two main aspects controlling phase separation efficiency: the grain size and the iron partitioning between melt and solids. For what concerns the issue of a basal magma ocean, our study suggests that the location of a density contrast between solid and magma must be considered of equal importance with that of the intersection between liquidus and isentrope.
Egalement dans la rubrique
- L'identification des plus anciennes traces de la vie - Julien Alleon (Site Buffon)
- Condrites à enstatite et origine de la Terre - Maud Boyet
- L'enzyme glycolytique aldolase : aspects mécanistiques et fonctions « moonlighting » - Jurgen Sygush
- Cumulant Green’s function approaches for excited states, x-ray spectra, and thermodynamic properties - John J. Rehr
- Molecular dynamics and quantum Monte Carlo, from planetary interiors to adiabatic quantum computing - Guglielmo Mazzola
- Changements microstructuraux et diversité microbienne associés à l’altération des silicates : influence sur les cinétiques de dissolution du laboratoire au terrain - Bastien Wild
- Advanced Structural and Chemical Characterization of Complex Materials at the Nanoscale: The cases of Misfit Nanotubes and Amorphous Carbon Thin Films - Luc Lajaunie
- Sulfures de fer, plus que des minéraux accessoires sur Mars - Jean-Pierre Lorand
- Coexistence, Interfacial Energy and the Fate of Microemulsions of 2D Dipolar Bosons - Massimo Boninsegni
- Western Australian iron ore and their toolkit of detection - Erick Ramanaidou
- Formation des chondres par recyclage de poussières primordiales dans le disque d'accrétion - Yves Marrocchi (Site Buffon)
- Multiferroic skyrmions - Maxim Mostovoy
- All models are wrong, some are useful: Predicting and designing interactions based on multiple wrong models - Yanay Ofran
- Overview and science applications of European XFEL - Thomas Tschentscher
- Les isotopes de l'oxygène dans le système solaire jeune vus par les inclusions réfractaires des météorites - Jérôme Aléon (Site Buffon)
- Investigation of the ground state of Au-supported FePc film based on the interpretation of Fe K- and L-edge XMCD - Calogero Natoli
- NANOPROBE Un projet international et collaboratif entre SOLEIL et MAXIV (Suède) : Instrumentation nouvelle à l’échelle du laboratoire - Stefan Kubsky
- Les variations isotopiques du sélénium dans les chondrites : un outil pour décrire la formation des sulfures? - Jabrane Labidi
- Mineral physics studies of planetary cores: from the Moon to the exoplanets - Guillaume Morard
- Les batteries Li-ion - Alain Mauger
- Ingénierie des protéines pour la chélation sélective de radionucléides comme l'uranium - Catherine Berthomieu
- Experimental constraints on melting in the MgO-SiO2 system at the lower mantle conditions - Marzena A. Baron
- Distribution of Hydrogen in the Deep Earth : reports from the lab, rumors from the fields, & consequences for our Planet - Sylvie Demouchy
- Dielectric Inversion of Induction Logs Application in Gas Shale Detection - Martin G. Lüling
- Asteroid surfaces: irradiation and VIS-NIR micro-spectroscopy in the laboratory - Rosario Brunetto (Site Buffon)
- Earth's Deep Water Cycle: Atomic to Geophysical Scales - Steven Jacobsen
- Late accretion history of the terrestrial planets inferred from platimium stables isotopes - John Creech (Site Buffon)
- Unweaving the fabric of the Universe - Mairi Sakellariadou
- Détermination expérimentale et spectroscopique des facteurs de fractionnement isotopique: les isotopes du fer, traceurs de la différenciation planétaire - Mathieu Roskosz
- Mars, le premier milliard d'années - Sylvain Bouley (Site Buffon)
Les séminaires ailleurs
Nous avons sélectionné quelques sites sur lesquels sont recensés des séminaires pouvant vous intéresser :
Semparis : les serveur des séminaires parisiens
LPTMC
SOLEIL
ESPCI
Laboratoire Léon Brillouin
INSP
IPGP
CEA
Colloquium
Pierre et Marie Curie
Contact
A. Marco Saitta
Directeur de l'institut
marco.saitta(at)sorbonne-universite.fr
Bruno Moal
Secrétaire général
33 +1 44 27 52 17
bruno.moal(at)sorbonne-universite.fr
Jérôme Normand
Gestion du personnel
Réservation des salles
jerome.normand(at)sorbonne-universite.fr
Antonella Intili
Accueil et logistique
Réservation des salles
antonella.intili(at)sorbonne-universite.fr
Ouafa Faouzi
Gestion financière
gestionimpmc@impmc.upmc.fr (gestionimpmc @ impmc.upmc.fr)
Cécile Duflot
Communication
cecile.duflot(at)sorbonne-universite.fr
33 +1 44 27 46 86
Contact unique pour l'expertise de matériaux et minéraux
Stages d'observation pour élèves de 3e et de Seconde
feriel.skouri-panet(at)sorbonne-universite.fr
Adresse postale
Institut de minéralogie, de physique des matériaux et de cosmochimie - UMR 7590
Sorbonne Université - 4, place Jussieu - BC 115 - 75252 Paris Cedex 5
Adresse physique
Institut de minéralogie, de physique des matériaux et de cosmochimie - UMR 7590 - Sorbonne Université - 4, place Jussieu - Tour 23 - Barre 22-23, 4e étage - 75252 Paris Cedex 5
Adresse de livraison
Accès : 7 quai Saint Bernard - 75005 Paris, Tour 22.
Contact : Antonella Intili : Barre 22-23, 4e étage, pièce 420, 33 +1 44 27 25 61
Fax : 33 +1 44 27 51 52