Slip Systems in MgSiO 3 Post-Perovskite: Implications for D ′′ Anisotropy

Abstract

Slippery When Squeezed The behavior of seismic waves as they pass through Earth's interior depends on the physical properties of major mineral phases at depth. If such minerals are anisotropic—that is, they influence seismic waves preferentially depending on crystallographic orientation—interpreting the structure of a region becomes more challenging. In the lowermost mantle, near the boundary with the outer core, deformation of MgSiO 3 post-perovskite may affect anisotropy. Miyagi et al. (p. 1639 ) solved previous experimental limitations to show that, when squeezed at high pressures, MgSiO 3 post-perovskite weakens and breaks along its (001) lattice plane. When modeled, this deformation pattern produces anisotropic structures that are consistent with seismic data collected from this region.