HR: 16:30h
AN: MR24A-03    [Abstracts]
TI: Deformation Experiments at High Pressures in Diamond Anvil Cells: Texture Development in MgSiO3 Perovskite
AU: Wenk, H
EM: wenk@seismo.berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720 United States
AU: * Pehl, J
EM: jenpehl@eps.berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Speziale, S
EM: speziale@berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Merkel, S
EM: merkel@eps.berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Shu, J
EM: j.shu@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution, Washington, DC 20015 United States
AU: Shen, G
EM: shen@cars.uchicago.edu
AF: GSECARS-CAT, Argonne National Laboratory, Argonne, IL 60439 United States
AU: Prakapenka, V
EM: prakapenka@cars.chicago.edu
AF: GSECARS-CAT, Argonne National Laboratory, Argonne, IL 60439 United States
AU: Mao, H D
EM: h.mao@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution, Washington, DC 20015 United States
AU: Mao, H D
EM: h.mao@gl.ciw.edu
AF: GSECARS-CAT, Argonne National Laboratory, Argonne, IL 60439 United States
AB: With increasing interest in the geodynamics of the lower mantle and seismic anisotropy in the deep earth, a better understanding of the deformation behavior of lower mantle minerals is essential. Pressure conditions in the lower mantle can at present only be achieved with diamond anvil cells (DAC) and thus we have conducted DAC deformation experiments up to 50 GPa on (Mg,Fe)SiO$_{3}$ perovskite, the major lower mantle phase. In order to quantify the reproducibility and accuracy of the technique, we investigated copper up to 25 GPa as a reference material to verify texture type and homogeneity. Our previous DAC experiments documented texture development during phase transformations from olivine to ringwoodite, and to perovskite + magnesiowuestite. The new experiments explored enstatite transforming to perovskite and confirmed strong texture development with (001) lattice planes at high angles to the compression direction. These experiments furthermore document strengthening of textures with time and significant changes during in situ heating, with grain growth, corresponding to recrystallization. While conditions are still far from those in the lower mantle (stress, strain rate and temperature particularly) DAC experiments shed light on the deformation mechanisms in high pressure phases that can be used for modeling geodynamic processes in the deep earth.
DE: 3924 High-pressure behavior
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
SC: Mineral and Rock Physics [MR]
MN: 2004 AGU Fall Meeting