HR: 13:40h
AN: MR13B-01 INVITED     [Abstracts]
TI: Integrated in-situ probes for structural and dynamic properties of geological materials at ultrahigh pressures and temperatures
AU: * Mao, H
EM: mao@gl.ciw.edu
AF: Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Mao, W L
EM: wmao@uchicago.edu
AF: Los Alamos National Laboratory, LANSCE-12, MS-H805, Los Alamos, NM 87545 United States
AB: Multiple x-ray and allied probes have been recently developed and integrated with diamond-anvil cells at synchrotron facilities. They have effectively opened up the vast field area of the Earth's interior to direct, in-situ study. For instance, x-ray emission spectroscopy identifies the high-spin-low-spin transition that governs Fe-Mg partitioning, the most important factor in element differentiation in the mantle. Inelastic x-ray near-edge spectroscopy reveals the bonding nature of light elements that control the phase transitions, structure and partitioning of these elements (e.g., carbon bonding changes as an element, and in oxides, carbonates, and silicates). X-ray diffraction combined with laser-heated diamond anvil cell determines crystal structures and P-V-T equations of state. Shear moduli, single-crystal elasticity, and phonon dynamics can be measured to the core pressures with newly-enabled, complementary techniques, including radial x-ray diffraction, nuclear resonant inelastic x-ray scattering, non-resonant inelastic x-ray scattering, high-temperature Raman spectroscopy, and Brillouin scattering spectroscopy. The nonhydrostatic stress in solid samples which was previously regarded as a nuisance that degraded the experiments, can now be used for extracting important rheological information, including deformation mechanisms, preferred orientation, slip systems, plasticity, failure, and shear strength of major mantle and core minerals at high pressures. With the new arsenal of experimental techniques over the extended P-T-x regimes at we can now address questions that were not conceivable only a decade ago. Knowledge of the high P-T properties is leading to fundamental improvements in interpreting seismological observations and understanding the structure, dynamics, and evolution of the Earth's deep interior.
DE: 3909 Elasticity and anelasticity
DE: 3924 High-pressure behavior
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 3994 Instruments and techniques
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005