HR: 14:15h
AN: U13C-03    [Abstracts]
TI: Geodynamic modelling of volatile-rich mantle melts
AU: * Leahy, G M
EM: Garrett.Leahy@Yale.edu
AF: Yale University Department of Geology and Geophysics, PO Box 208109, New Haven, CT 06520-8109, United States
AU: Bercovici, D
EM: david.bercovici@yale.edu
AF: Yale University Department of Geology and Geophysics, PO Box 208109, New Haven, CT 06520-8109, United States
AB: Many difficulties remain in modelling the evolution of mantle chemistry, particularly with respect to the treatment of silicate melts. Given plausible scales of mantle heterogeneity and reasonable melt migration velocities (relative to mantle flow), it is likely that most silicate melts are not in thermodynamic equilibrium with their source rock. These effects are more significant for chemically derived melts, where time scales for diffusive equilibrium are much greater than that of thermal equilibration. Further, two-phase continuum approaches break down in this regime, as partial melts give way to dike formation, fingering instabilities, and lensing. Here we describe a new method for the theoretical treatment of the dynamic and chemical stability of silicate melts in the mantle. Our method explores the feedback between dynamic transport (due to gravitational forcing and differing material properties between the solid and melt) and chemical reactions that convert solid to melt (and vice-versa) due to thermodynamic disequilibrium. This method can be used to address the stability of silicate melts in a wide variety of tectonic environments under many different chemical conditions.
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8121 Dynamics: convection currents, and mantle plumes
DE: 8412 Reactions and phase equilibria (1012, 3612)
DE: 8434 Magma migration and fragmentation
SC: Union [U]
MN: 2007 Fall Meeting