HR: 1330h
AN: V42A-0331    [PDF]
TI: Effects of Iron and Aluminum on Thermoelastic Properties of Magnesium Silicate Perovskite
AU: * Nishiyama, N
AF: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Japan
AU: Yagi, T
EM: yagi@issp.u-tokyo.ac.jp
AF: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Japan
AU: Harada, T
AF: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Japan
AU: Ono, S
AF: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Japan
AU: Gotou, H
AF: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Japan
AU: Kikegawa, T
AF: Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Ooho, Tsukuba, 305-0801 Japan
AB: In the present study, effects of iron and aluminum on thermoelastic properties of magnesium silicate perovskite have been studied by in-situ X-ray diffraction experiments using a Kawai-type apparatus with sintered diamond anvils as the second stage anvils. Two kinds of starting materials were used; one is a powder of San Carlos orthopyroxene that contained iron (5.9 wt percent) and aluminum (4.4 wt percent), and the other is a powder of single crystal of enstatite, which was mixed with gold as an internal pressure calibrant. These two starting materials were enclosed separately in two sample capsules made of semi-sintered magnesia, in the same pressure cell. Thus, we were able to measure unit cell volumes of end-member MgSiO3-perovskite and the iron and aluminum-bearing counterpart (0.05 Al and 0.05 Fe for 3 oxygens) under identical pressure and temperature conditions. The unit cell volumes were measured at pressures of 19-32 GPa and temperatures of 300-1500 K. Specific volumes (V/V0) of these two perovskites that are measured at the same pressure and temperature conditions are consistent with each other within experimental errors through the whole pressure and temperature range, which suggests that incorporation of iron and aluminum has no observable effect on thermoelastic properties of silicate perovskite at these pressure and temperature conditions. The determined bulk moduli of MgSiO3- and iron and aluminum-bearing perovskites at ambient conditions are 248(6) GPa and 250(4) GPa, respectively, which is consistent with the study using diamond anvil cell coupled with CO2 laser-annealing technique by Andrault et al. (EPSL, 193, 501-508, 2001).
DE: 3919 Equations of state
DE: 3949 Thermal expansivity
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting