HR: 14:28h
AN: MR23D-05    [Abstracts]
TI: New Constraints on the Pyrolitic Model: In Situ X-ray Diffraction Measurements on KLB-1 Peridotite Under the Lower Mantle Conditions
AU: * Ricolleau, A
EM: a.ricolleau@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AU: Fei, Y
EM: y.fei@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AU: Cottrell, E
EM: cottrellE@si.edu
AF: Smithsonian Institution, National Museum of Natural History, Department of Mineral Sciences, P.O. Box 37012, Washington, DC 20013, United States
AU: Watson, H
EM: watson40@llnl.gov
AF: Lawrence Livermore National Laboratory, Earth and environment, 7000 east Avenue L-206, Livermore, CA 94550, United States
AU: Deng, L
EM: l.deng@ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AU: Zhang, L
EM: lzhang@ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AU: Fiquet, G
EM: guillaume.fiquet@impmc.jussieu.fr
AF: Institut de Physique du Globe de Paris, IMPMC, Mineralogie, 140 rue de Lourmel, Paris, 75015, France
AU: Auzende, A
EM: auzende@impmc.jussieu.fr
AF: Institut de Physique du Globe de Paris, IMPMC, Mineralogie, 140 rue de Lourmel, Paris, 75015, France
AU: Roskosz, M
EM: mathieu.roskosz@univ-lille1.fr
AF: Laboratoire de Structure et Propriétés de l'Etat Solide, Universite des Sciences et Techniques de Lille Bat C6, Villeneuve d'Ascq, 59655, France
AU: Morard, G
EM: guillaume.morard@gmail.com
AF: European Synchrotron Radiation Facility, 6 Rue Jules Horowitz BP 220, Grenoble, 38043, France
AU: Prakapenka, V
EM: prakapenka@cars.uchicago.edu
AF: Center for Advanced Radiation Sources, University of Chicago, 9700 S. Cass Ave, Argonne, IL 60439, United States
AB: Composition of the Earth\'{ }s lower mantle remains an essential question in Earth sciences. Modeling of lower mantle composition is generally obtained by comparing mineral physics data and seismic observations, using measured properties of the lower mantle end-member phases such as perovskite and ferropericlase. In this study, in situ X-ray diffraction patterns were collected from 30 GPa to 110 GPa and from 1400 K to 2500 K using KLB-1 peridotite as starting material. The experiments were performed in laser-heated diamond-anvil cell at the Advanced Photon Source and at the European Synchrotron Radiation Facility. The sample was loaded in neon pressure medium. We observe the three lower mantle phases at all pressures, i.e., magnesium-iron silicate perovskite, ferropericlase and calcium silicate perovskite, and report molar volume changes as a function of pressure and temperature. We notice the high spin to low spin transition of iron in the ferropericlase at room temperature and also at high temperature. The equations of state (EOS) of the two perovskites and ferropericlase are determined using Au as internal pressure standard. We also examine the Fe/Mg partitioning between Mg- perovskite and ferropericlase with analytical TEM carried out on recovered samples, and the phase proportion from the Rietveld refinement of X-ray diffraction patterns. Using the volume data and chemical composition information, we calculate the densities of peridotite along geotherm of the Earth. The calculations explore the effect of Fe/Mg partitioning variation and the accompanied change in the phase proportion on the densities. Our calculated density profile allows us to make direct comparison with the seismic observations and evaluate current composition mantle models.
DE: 1025 Composition of the mantle
DE: 3620 Mineral and crystal chemistry (1042)
DE: 3630 Experimental mineralogy and petrology
DE: 3919 Equations of state
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting