HR: 0800h
AN: V51E-0834    [Abstracts]
TI: Molecular Dynamics Simulation of Isotope Fractionation in a Temperature Gradient
AU: * Lacks, D J
EM: daniel.lacks@case.edu
AF: Case Western Reserve University Dept. of Chemical Engineering, 10900 Euclid Avenue, Cleveland, 44106, United States
AU: Van Orman, J A
EM: james.vanorman@case.edu
AF: Case Western Reserve University Dept. of Geological Sciences, 10900 Euclid Avenue, Cleveland, 44106, United States
AB: Recent experimental work on silicate melts has shown that isotopes may be fractionated by Soret diffusion along a temperature gradient. The magnitude of the fractionation is surprisingly large and not well understood. We carried out non-equilibrium molecular dynamics simulations on silicate melts with an imposed steady-state temperature gradient, with the goal of gaining insight into the physical mechanisms that underlie these experimental results. Two isotopes of each element are included, and a steady-state spatial distribution of elements and isotopes is achieved. In agreement with experiments, we find that heavy isotopes are concentrated in the cold region, as are Mg and other network-modifying cations. The detailed physical origins of these behaviors will be discussed.
DE: 1037 Magma genesis and partial melting (3619)
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 3640 Igneous petrology
DE: 4255 Numerical modeling (0545, 0560)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting