HR: 09:36h
AN: U11B-08    [Abstracts]
TI: Quantifying the Flux of Slab Material Through the Transition Zone and Beyond
AU: * King, S D
EM: sdk@vt.edu
AF: Virginia Tech Geosciences, 4044 Derring Hall (0420), Blacksburg, VA 24061, United States
AB: While tomographic images are interpreted as the present day location of subducted slabs in the mantle, the variety of slab morphologies imaged suggests that slabs meet significant resistance at the upper part of the lower mantle. Unfortunately, these images only provide a qualitative estimate of the flux of material through the transition zone. It is known that the Clapeyron slope of the ringwoodite to perovskite plus ferropericlase phase transformation, the viscosity of the lower mantle, the effect of pressure on the coefficient of thermal expansion, the rate of trench migration, and the composition, thermal structure and rheology of the slab impact the dynamics of deeply subducted slabs. Previous attempts to quantify the flux of material through the transition zone have included following passive tracers, using two-point correlation functions, and the flow-based mass-flux diagnostic. Passive tracers are ideal for tracking the fate of slab; however it is difficult to use passive tracers to actually quantify the flux upper mantle material (if any) that is entrained with the slab into the lower mantle. The two-point correlation function is useful for identifying layering and can be related to the mass flux diagnostic, the most direct measure of the vertical flux of material in a fluid system. I will illustrate the mass flux diagnostic and two-point correlation function on some easy to interpret flows and then speculate on the two-point correlation function calculations from tomographic models.
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8147 Planetary interiors (5430, 5724, 6024)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Union [U]
MN: 2007 Fall Meeting