HR: 15:10h
AN: T13F-07    [Abstracts]
TI: A Combined Geodynamic-Tomography Investigation into Thermochemical Piles in the Lower Mantle beneath Africa and the Pacific
AU: * Bull, A L
EM: abigail.bull@asu.edu
AF: Arizona State University, Department of Geological Sciences Box 871404 , Tempe, AZ 85287-1404 United States
AU: McNamara, A K
EM: allen.mcnamara@asu.edu
AF: Arizona State University, Department of Geological Sciences Box 871404 , Tempe, AZ 85287-1404 United States
AU: Ritsema, J
EM: j.ritsema@gmail.com
AF: The University of Michigan, Department of Geological Sciences 2534 C. C. Little Building, 1100 North University Ave, Ann Arbor, MI 48109-1005 United States
AB: Seismic tomography reveals large, low-velocity anomalies in the lower mantle beneath Africa and the Pacific. Heterogeneous mantle models typically place the anomalies into the context of thermochemical piles, characterized by a different, denser composition than the surrounding region. We investigate these structures using spherical thermochemical and isochemical convection calculations with imposed Earth-like boundary conditions. Due to the heterogeneous resolution of tomographic models, we must carefully compare our numerical models to the tomographic models. We choose to filter the numerical images by convolving them with the resolution matrix of the tomographic model S20RTS. This filter applies the inversion artifacts of S20RTS to the numerical models, allowing us to investigate the "blurring and smearing" that compromise the quality of the seismic images, and their effect on model interpretation. We develop statistical correlation methods to compare filtered geodynamic model predictions to observed tomography. We aim to investigate the necessity of a thermochemical component to produce the anomalies in the lower mantle observed by tomography. The procedure of tomographically filtering geodynamic model data may lead to a more-detailed, reliable understanding of the parameters required in geodynamic models to produce the anomalous structures observed beneath Africa and the Pacific.
DE: 0545 Modeling (4255)
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)
SC: Tectonophysics [T]
MN: Fall Meeting 2005