HR: 09:45h
AN: MR21A-08    [Abstracts]
TI: Dynamics of Metal-Silicate Separation in a Terrestrial Magma Ocean
AU: * Hoink, T
EM: hoeink@uni-muenster.de
AF: Institut für Geophysik, Universität Münster, Corrensstrasse 24, Münster, 48149 Germany
AU: Schmalzl, J
EM: joergs@earth.uni-muenster.de
AF: Institut für Geophysik, Universität Münster, Corrensstrasse 24, Münster, 48149 Germany
AU: Hansen, U
EM: hansen@earth.uni-muenster.de
AF: Institut für Geophysik, Universität Münster, Corrensstrasse 24, Münster, 48149 Germany
AB: In a terrestrial magma ocean, the metal-silicate separation involved small metal droplets. Our goal is to better understand the dynamics of the metal droplet scenario. The mechanism of sedimentation in a vigorously convecting and strongly rotating magma ocean may differ significantly from settling droplets in still fluid. In order to systematically study the parameter dependence on the style of motion we utilize 2D and 3D convection models combined with a tracer-based sedimentation method. We investigate the characteristic flow patterns resulting from the competing effects of convection and droplet settling and find three styles of motion: a temperature-dominated style where most droplets remain suspended, a droplet-dominated style where the droplets separate from the fluid and a style of repetitive motion. The droplet dominated style is relevant to the magma ocean. In this scenario the droplets settle and form a dense bottom layer. We identify a time scale that is characteristic for the separation of metal droplets from the liquid silicate. Finally we study the chemical interaction of settling metal droplets and liquid silicate in a magma ocean. For a number of cases we compute the resulting Ni core-mantle partition coefficient.
DE: 0500 COMPUTATIONAL GEOPHYSICS (3200, 3252, 7833)
DE: 1009 Geochemical modeling (3610, 8410)
DE: 8125 Evolution of the Earth (0325)
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005