HR: 10:35h
AN: MR52A-02 INVITED    [Abstracts]
TI: Constraints on Lateral Variations in Temperature and Composition in the Upper Mantle From Inversion of Long Period Seismic Waveforms.
AU: * Romanowicz, B A
EM: barbara@seismo.berkeley.edu
AF: Berkeley Seismological Laboratory, 215 McCone Hall, Berkeley, CA 94720, United States
AU: Cammarano, F
EM: fabio@seismo.berkeley.edu
AF: Berkeley Seismological Laboratory, 215 McCone Hall, Berkeley, CA 94720, United States
AU: Stixrude, L
EM: stixrude@umich.edu
AF: Department of Geological Sciences, Univ. of Michigan, 2534 C C Little Bldg, Ann Arbor, MI 48109, United States
AU: Lithgow-Bertelloni, C
EM: crlb@umich.edu
AF: Department of Geological Sciences, Univ. of Michigan, 2534 C C Little Bldg, Ann Arbor, MI 48109, United States
AU: Xu, W
EM: xuwenbo@umich.edu
AF: Department of Geological Sciences, Univ. of Michigan, 2534 C C Little Bldg, Ann Arbor, MI 48109, United States
AB: Our goal is the construction of a model of lateral variations in temperature and composition in the upper mantle obtained directly from the inversion of a global collection of long period three component multimode seismic waveforms. We start from a reference 1D model corresponding to a known pyrolite composition and a 60My geotherm connected with a 1300oC mantle adiabat, which was obtained by Monte-Carlo inversion of a global dataset of body wave travel times and fundamental mode free oscillation frequencies. We first inverted for lateral variations in temperature alone, taking into account the non-linear effects of anelasticity, and including corrections for radial anisotropy. Temperature can explain a large part of the signal contained in the waveforms, however, under cratons, a compositional signature is present. Also, the average 1D profile obtained from such an inversion is not compatible with a dry pyrolite composition, but rather, suggests a gradual enrichment in a garnet rich component with depth. Starting from our 3D temperature model, we present the first results of waveform inversion, utilizing both phase and amplitude information, and including lateral variations in composition, parametrized in terms of basalt depletion.
DE: 3900 MINERAL PHYSICS
DE: 3909 Elasticity and anelasticity
DE: 7200 SEISMOLOGY
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7270 Tomography (6982, 8180)
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting