HR: 16:45h
AN: DI14A-04 INVITED    [Abstracts]
TI: Predicting Seismological and Geochemical Observations Using Global and Regional 3-D Spherical Convection Models Incorporating Self-Consistently Calculated Mineral Physics
AU: * Tackley, P J
EM: ptackley@ethz.ch
AF: ETH Zurich, Institute for Geophysics Schafmattstrasse 30, Zurich, 8093, Switzerland
AU: Nakagawa, T
EM: takashi@geo.kyushu-u.ac.jp
AF: Kyushu University, Department of Earth and Planetary Sciences, Fukuoka, 12345, Japan
AU: Deschamps, F
EM: frederic.deschamps@erdw.ethz.ch
AF: ETH Zurich, Institute for Geophysics Schafmattstrasse 30, Zurich, 8093, Switzerland
AU: Connolly, J A
EM: james.connolly@erdw.ethz.ch
AF: ETH Zurich, Institute of Mineralogy and Petrology Clausiusstrasse 25, Zurich, 8092, Switzerland
AU: Duchoiselle, L
EM: lionel.duchoiselle@erdw.ethz.ch
AF: ETH Zurich, Institute for Geophysics Schafmattstrasse 30, Zurich, 8093, Switzerland
AB: The latest generation of the global 3-D spherical convection model yinyang-Stag3D allows the direct computation of a planet's thermo-chemical evolution, including self-consistently generated plate tectonics, chemical differentiation induced by melting, large viscosity variations, and a realistic treatment of phase diagrams and material properties. The latter has recently been added using free energy minimization to compute stable phases as a function of temperature, pressure, and composition as expressed by ratios of the five main oxides, and thus avoids the need for increasingly complicated and ad hoc parameterizations of phase transitions. Modern supercomputers and clusters also allow increasingly higher resolution, with up to 1.2 billion unknowns possible on only 32 dual-processor nodes of an opteron cluster. In ongoing research, results from such modeling efforts are compared to a wide range of seismological observations, ranging from statistical comparisons with global tomographic inversions (standard and probabilistic), and comparisons with regional models, for example of D" structure and heterogeneity, including structures that are sharp-sided and/or related to the post-perovskite phase transition. Such results also have implications for geochemistry including the possible location of "reservoirs". For high-resolution studies, a region of a sphere, instead of a whole sphere, can be modeled, and in this mode models of slab-CMB interaction are presented that show some of the small-scale thermo-compositional-phase structures that can be generated. Global models also allow the computation of planetary secular cooling, including prediction of how the core heat flux varies with time hence the evolution of the geodynamo, and possible transitions in plate tectonic mode. Thus, a suite of predictions can be made.
DE: 7208 Mantle (1212, 1213, 8124)
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: Study of the Earth's Deep Interior [DI]
MN: 2007 Fall Meeting