Earth and Planetary Science
EPS Near-Surface Geochemistry and Geobiology

AUG 2007 - Post-Perovskite and D'' Anisotropy

In a recent issue of Science (reprint) researchers from Berkeley (Miller fellows Sebastien Merkel and Sergio Speziale, graduate student Lowell Miyagi and EPS faculty Rudy Wenk), Arizona State University, Princeton and the Advanced Photon Source at Argonne report on experimental deformation of the mineral phase postperovskite MgSiO3 with diamond anvil cells at pressures of 150 GPa. This phase is supposed to constitute the D" layer in the earth, just above the liquid core boundary. Using information about deformation mechanisms derived from the experiments the team then model the evolution of anisotropy in the deep earth that seismologists have observed.