HR: 1340h
AN: MR23B-0052    [Abstracts]
TI: Structures and dynamics in the lower and lowermost mantle: Effects of density crossover in the transition zone and post-perovskite phase change in the CMB region
AU: * Nakagawa, T
EM: takashi@eps.s.u-tokyo.ac.jp
AF: Department of Earth and Planetary Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033 Japan
AU: Tackley, P
EM: ptackley@ucla.edu
AF: Institute of Geophysics, ETH-Zurich, HPP L13, Hoenggerberg, Zurich, CH-8093 Switzerland
AB: Three-dimensional thermo-chemical multiphase models of mantle convection are used to investigate characteristic structures and dynamics in the lower mantle region: (1) strongly heterogeneous stuff in the core-mantle boundary region and (2) small-scale material transfer through the 660km depth. In order to treat with both interesting features in the lower mantle, post-perovkite phase change that is included in both phase change systems (olvine-spinel-perovskite and pyroxene-garnet-perovskite) is necessary as well as having the density crossover between two phase change systems. However, our previous study [Nakagawa and Tackley, 2005 in MIT conference] did not assume effects of post-perovskite phase change with the multi-component phase system between olivine and pyroxene systems. That study also indicated that the post-perovskite phase change could tend to destabilize the compositionally-distinct layering above the core-mantle boundary that has been already shown in two-dimensional cases [Nakagawa and Tackley, 2005 in EPSL] and compositional stratification due to the density crossover between the olivine and pyroxene systems in the transition zone. In this study, combining those two effects caused by complicated phase changes of olivine and pyroxene material in a convecting mantle, the structure and dynamics in the lower and lowermost mantle would be revealed in three-dimensional models.
DE: 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124)
DE: 1213 Earth's interior: dynamics (1507, 7207, 7208, 8115, 8120)
DE: 8121 Dynamics: convection currents, and mantle plumes
DE: 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105)
DE: 8125 Evolution of the Earth (0325)
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005