HR: 14:40h
AN: MR23D-06 INVITED    [Abstracts]
TI: Constraints on Mantle Composition from Ultrasonic Velocity Measurements at High P and T
AU: * Li, B
EM: Baosheng.Li@stonybrook.edu
AF: Stony Brook University, ESS Buildin Mineral Physics Institute, Stony Brook, NY 11794, United States
AU: Liu, W
EM: Wei.Liu@stonybrook.edu
AF: Stony Brook University, ESS Buildin Mineral Physics Institute, Stony Brook, NY 11794, United States
AB: Elasticity measurements at high pressure and high temperatures provide crucial data for testing and constraining possible mineralogical composition of the Earth's deep interior. Advanced ultrasonic techniques in conjunction with state-of-the-art synchrotron facilities can now allow us to conduct simultaneous measurements of sound velocities and density to P-T conditions up to 25-28 GPa and 1600K. Using these techniques, new results have been obtained for many important mantle phases, including olivine, wadsleyite, calcium silicate perovskite, and magnesium silicate perovskite through a thermodynamically self-consistent finite strain data analysis approach, proving an updated mineral physics elasticity database for the study of physical properties of mantle phases as well as aggregate models with different mineralogical compositions. We have calculated phase equilibrium and volume fractions for pyrolite and piclogite models by minimizing the free energy of the mineralogical assemblages at mantle depths, the compressional and shear wave velocities and density profiles are then compared with global and regional seismic data from the upper mantle to the bottom of the transition zone. Details of the comparison to distinguish pyrolite and piclogite at the different regions of the upper mantle and transitions zone as well as their comparison with the velocity gradient and discontinuities in the transition zone, will be discussed.
DE: 1025 Composition of the mantle
DE: 3630 Experimental mineralogy and petrology
DE: 3909 Elasticity and anelasticity
DE: 3919 Equations of state
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting