HR: 0830h
AN: S21E-0369    [PDF]
TI: Extension of (Mg$_{0.64}$Fe$_{0.36}$)O Ferropericlase Equation of State Measurements to 25 GPa and 2173 K
AU: * van Westrenen, W
EM: willem@erdw.ethz.ch
AF: Institut f\"{u}r Mineralogie und Petrographie, ETH Z\"{u}rich, Z\"{u}rich, 8092 Switzerland
AU: Li, J
EM: jackielie@uiuc.edu
AF: Dept of Geology, University of Illinois, Urbana Champaign, Urbana, IL 61801 United States
AU: Fei, Y
EM: fei@gl.ciw.edu
AF: Geophysical Lab, Carnegie Institution of Washington, Washington, DC 20015 United States
AU: Frank, M R
EM: mfrank@niu.edu
AF: Dept of Geology and Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115 United States
AU: Funakoshi, K
EM: funakosi@spring8.or.jp
AF: SPring-8/JASRI, Mikazuki-cho, Sayo-gun, Hyogo, 679-5198 Japan
AU: Hellwig, H
EM: hhellwig@uiuc.edu
AF: Dept of Geology, University of Illinois, Urbana Champaign, Urbana, IL 61801 United States
AU: Komabayashi, T
EM: tkomabay@geo.titech.ac.jp
AF: Dept of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8551 Japan
AU: Mibe, K
EM: k.mibe@gl.ciw.edu
AF: Geophysical Lab, Carnegie Institution of Washington, Washington, DC 20015 United States
AU: Minarik, W G
EM: minarik@gl.ciw.edu
AF: Geophysical Lab, Carnegie Institution of Washington, Washington, DC 20015 United States
AU: Van Orman, J A
EM: jav12@cwru.edu
AF: Dept of Geological Sciences, Case Western Reserve University, Cleveland, OH 44106 United States
AU: Watson, H C
EM: watsoh@rpi.edu
AF: Dept of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180 United States
AB: We present an updated equation of state (EOS) for (Mg$_{0.64}$Fe$_{0.36}$)O ferropericlase (FP), the most voluminous oxide in the Earth's lower mantle, based on a new set of $PVT$ measurements. FP volumes were determined {\it in situ} in a multi-anvil apparatus, at pressures up to 25 GPa and temperatures up to 2173 K, with energy-dispersive X-ray diffraction at the SPring-8 synchrotron facility. Au and MgO were used as pressure markers. Including previous measurements by Fei et al. (PCM 1992) and Zhang and Kostak (PEPI 2002), 165 $PVT$ points are now available for this material. Data were fitted to high-temperature Birch-Murnaghan and Mie-Gr\"{u}neisen-type EOS. As an example of the attainable accuracy, our Birch-Murnaghan EOS reproduces experimental pressures for all 165 data points to within 0.28 GPa ($1\sigma$), with a maximum deviation of 0.8 GPa. The revised FP EOS is compared with recent EOS data for pure MgO, to assess possible variations in FP thermodynamic properties at lower mantle $PT$ conditions as a function of FP iron content.
DE: 1025 Composition of the mantle
DE: 3672 Planetary mineralogy and petrology (5410)
DE: 3919 Equations of state
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
SC: Seismology [S]
MN: 2003 Fall Meeting