HR: 11:20h
AN: MR22A-05    [Abstracts]
TI: Ferromagnesian Post-Perovskite Silicates in the D" Conditions
AU: * Mao, W L
EM: wmao@uchicago.edu
AF: University of Chicago, Department of the Geophysical Sciences 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AU: * Mao, W L
EM: wmao@uchicago.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road, Washington, DC 20015 United States
AU: Shen, G
EM: shen@cars.uchicago.edu
AF: University of Chicago, Center for Advanced Radiation Sources 5640 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Prakapenka, V
EM: prakapenka@cars.uchicago.edu
AF: University of Chicago, Center for Advanced Radiation Sources 5640 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Meng, Y
EM: ymeng@hpcat.aps.anl.gov
AF: HPCAT, Advanced Photon Source Argonne National Laboratory 9700 South Cass Avenue, Argonne, IL 60439 United States
AU: Campbell, A J
EM: a-campbell@uchicago.edu
AF: University of Chicago, Department of the Geophysical Sciences 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Heinz, D L
EM: heinz@geosci.uchicago.edu
AF: University of Chicago, Department of the Geophysical Sciences 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Heinz, D L
EM: heinz@geosci.uchicago.edu
AF: Univeristy of Chicago, James Franck Institute 5640 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Shu, J
EM: shu@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road, Washington, DC 20015 United States
AU: Hemley, R J
EM: hemley@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road, Washington, DC 20015 United States
AU: Mao, H
EM: mao@gl.ciw.edu
AF: University of Chicago, Department of the Geophysical Sciences 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Mao, H
EM: mao@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington 5251 Broad Branch Road, Washington, DC 20015 United States
AU: Mao, H
EM: mao@gl.ciw.edu
AF: Univeristy of Chicago, James Franck Institute 5640 S. Ellis Avenue, Chicago, IL 60637 United States
AB: The D" boundary layer between the crystalline silicate mantle and molten iron core displays the largest contrast in physical and chemical properties of all the regions in the Earth, and undoubtedly plays a pivotal role in global dynamics and evolution. Recent high pressure-temperature {\it (P-T)} experiments and {\it ab-initio} theoretical calculations indicate that the pure end-member MgSiO$_{3}$ transforms to a post-perovskite (ppv) phase with the CaIrO$_{3}$ structure. Natural olivine with 12 mole percent Fe$_{2}$SiO$_{4}$ and synthetic orthopyroxenes with 20 and 40 percent FeSiO$_{3}$ were studied at high pressure-temperature to explore the possible incorporation of iron into ppv. The studies were conducted at Sector 13 (GSECARS) and 16 (HPCAT) of the Advanced Photon Source, Argonne National Laboratory. Samples were compressed in a diamond anvil cell and laser-heated. All samples were found to convert entirely or partially into the ppv structure, which was recently reported for pure MgSiO$_{3}$. With the liquid core as an unlimited reservoir of iron, core-mantle reactions could further enrich the iron content in this phase and explain the intriguing seismic signatures observed in the D" layer.
DE: 3900 MINERAL PHYSICS
DE: 3924 High-pressure behavior
SC: Mineral and Rock Physics [MR]
MN: 2004 AGU Fall Meeting