Strength and Elasticity of Mantle Minerals by Radial X-Ray Diffraction and Brillouin Spectroscopy

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DuffyEAR-0125675In this project, the investigators will study rheological and elastic properties of mantle minerals by combining new radial x-ray diffraction techniques with Brillouin spectroscopy in a diamond anvil cell. Radial x-ray diffraction is a new high-pressure method that can constrain a wealth of information about single-crystal elastic constants, yield strength, strength anisotropy, stress continuity, texturing, and even the equation of state. Advantages of radial diffraction relative to other techniques for strength and elasticity determination are that the accessible pressure range reaches into the deep lower mantle and there is no requirement for high-quality single crystals. A major goal of this study is to explore the capabilities of radial x-ray diffraction by choosing a set of materials for which the investigators can simultaneously apply radial diffraction to 60 GPa and Brillouin scattering on single crystals to 20 GPa. This will provide a direct comparison of elasticity determined by the new lattice strain methods with well-established Brillouin techniques. Specific materials to be examined included perovskites, magnesiowustites, spinel, corundum, brucite, and calcium oxide. These results will have fundamental and wide applications to high-pressure studies and our understanding of the Earth's deep mantle.