HR: 1340h
AN: MR43C-1518    [Abstracts]
TI: Elasticity of Fayalite and Spinel Polymorph of Fe2SiO4 at High Pressure and Temperature
AU: * Liu, Q
EM: qioliu@notes.cc.sunysb.edu
AF: Mineral Physics Institute, Stony Brook University, 255 Earth and Space Sciences Bldg., Stony Brook, NY 11794-2100, United States
AU: Liu, W
EM: weiliu3@notes.cc.sunysb.edu
AF: Mineral Physics Institute, Stony Brook University, 255 Earth and Space Sciences Bldg., Stony Brook, NY 11794-2100, United States
AU: Wang, L
EM: liping.wang@sunysb.edu
AF: Mineral Physics Institute, Stony Brook University, 255 Earth and Space Sciences Bldg., Stony Brook, NY 11794-2100, United States
AU: Li, B
EM: bli@notes.cc.sunysb.edu
AF: Mineral Physics Institute, Stony Brook University, 255 Earth and Space Sciences Bldg., Stony Brook, NY 11794-2100, United States
AU: Lindsley, D
EM: donald.lindsley@sunysb.edu
AF: Mineral Physics Institute, Stony Brook University, 255 Earth and Space Sciences Bldg., Stony Brook, NY 11794-2100, United States
AB: Fayalite is the iron end-member of the olivine solid solution series. Although there is an extensive set of accurate data about the elastic properties of forsterite, the elasticity data for fayalite end-member is sparse, especially at both high pressure and temperature conditions. In this study, elastic wave velocity measurements on polycrystalline fayalite and its high pressure polymorph spinel at high pressure and temperature were carried out using simultaneous X-ray diffraction, X-ray radiography, and ultrasonic interferometry. The experiment was conducted in a DIA-type cubic anvil apparatus (SAM85) installed at the superwiggler beamline X17B2 in Brookhaven National Laboratory. Ultrasonic data were acquired using a dual mode lithium niobate transducer (10 degree Y-cut, 30 MHz for S wave and 50 MHz for P wave). Boron epoxy cube was used as pressure transmitting medium. The sample was placed in the center of the cube with NaCl and BN as surrounding material. Double polished alumina rod was used as buffer rod. Energy-dispersive X-ray diffraction data for the sample and NaCl were collected for phase identification, density determination, and pressure calculation. Sample length was monitored by X-ray radiographic imaging. Travel time, sample length, and cell parameters were collected along multiple heating/cooling cycles up to 4 GPa and 673 K for fayalite and 7.5 GPa and 1173 K for spinel, from which compressional and shear wave velocities, elastic bulk and shear moduli for both phases can be derived. These results are important in studying the effect of iron on the physical properties of the solid solutions of Mg and Fe end-members at upper mantle and transition zone conditions.
DE: 3630 Experimental mineralogy and petrology
DE: 3909 Elasticity and anelasticity
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 3939 Physical thermodynamics
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting