Science, 311, pp. 644-646, (2006) [doi: 10.1126/science.1121808]
Plastic Deformation of MgGeO3 Post-Perovskite at Lower Mantle Pressures
S. Merkel, A. Kubo, L. Miyagi, S. Speziale, T. S. Duffy, H.-K. Mao and H.-R. Wenk
Polycrystalline MgGeO3 post-perovskite was plastically deformed in the diamond anvil cell between 104 and 130 gigapascals confining pressure and ambient temperature. In contrast with phenomenological considerations suggesting (010) as a slip plane, lattice planes near (100) became aligned perpendicular to the compression direction, suggesting that slip on (100) or (110) dominated plastic deformation. With the assumption that silicate post-perovskite behaves similarly at lower mantle conditions, a numerical model of seismic anisotropy in the D" region implies a maximum contribution of post-perovskite to shear wave splitting of 3.7% with an oblique polarization.
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