HR: 0800h
AN: MR31A-0140    [Abstracts]
TI: Single-crystal elastic properties of hydrous olivine
AU: Wang, J
EM: jwang11@uiuc.edu
AF: University of Illinois at U-C, 245 NHB 1301 W Green St, Urbana, IL 61801, United States
AU: Lakshanov, D
EM: lakshtan@uiuc.edu
AF: University of Illinois at U-C, 245 NHB 1301 W Green St, Urbana, IL 61801, United States
AU: Litasov, K
EM: klitasov@ganko.tohoku.ac.jp
AF: Institute of Mineralogy, Petrology and Economic Geology Faculty of Science Tohoku University, Aoba-ku, Sendai, 980-8578, Japan
AU: Morgenstern, M
EM: mmorgens@uiuc.edu
AF: University of Illinois at U-C, 245 NHB 1301 W Green St, Urbana, IL 61801, United States
AU: Ohtani, E
EM: ohtani@mail.tains.tohoku.ac.jp
AF: Institute of Mineralogy, Petrology and Economic Geology Faculty of Science Tohoku University, Aoba-ku, Sendai, 980-8578, Japan
AU: * Bass, J
EM: jaybass@uiuc.edu
AF: University of Illinois at U-C, 245 NHB 1301 W Green St, Urbana, IL 61801, United States
AB: Brillouin scattering measurements were performed on hydrous olivine (Fo93) with 0.6wt% water at ambient conditions. The single-crystal elastic moduli were obtained from three pre-orientated samples that allowed velocities to be obtained in the (100), (010), (011) planes at ambient condition. From the single crystal moduli, the aggregate elastic moduli (VRH averages) are K_S = 128.6(11) GPa and μ = 79.0(3) GPa for the adiabatic bulk modulus and shear modulus, respectively. The aggregate velocities are V_P = 8.43(4) km/s and V_S = 4.90(1) km/s for the compressional velocity and shear velocity, respectively. Comparing the results of this investigation with those of previous studies on anhydrous olivine with similar Fe contents, our results indicate the hydration has little effect on elastic properties of olivine at ambient conditions. Alternatively, our results may suggest that the previous studies underestimated the hydrogen content in the olivine samples used. It would appear that the velocity jump across the 410 km discontinuity in a wet mantle will be depend mostly on the water content of wadsleyite, since the elastic properties of this phase have been found to be far more sensitive to the H content of the sample. High pressure measurements are in progress. The high pressure derivatives of elastic moduli of hydrous olivine and hydrous wadsleyite are critical for constraining the water content hidden in the mantle transition zone.
DE: 3630 Experimental mineralogy and petrology
DE: 3900 MINERAL PHYSICS
DE: 3909 Elasticity and anelasticity
DE: 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105)
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting