Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000 degrees C
Abstract
Acoustic wave velocities for synthetic polycrystalline pyrope (Mg{sub 3}Al{sub 2}Si{sub 3}O{sub 12}) were measured to 9 GPa and temperatures up to 1000 degrees C by ultrasonic interferometry combined with energydispersive synchrotron Xray diffraction in a cubicanvil DIAtype apparatus (SAM85). Specimen lengths at high pressures (P) and temperatures (T) are directly measured by Xradiographic methods. Elastic wave travel times and Xray diffraction data were collected after heating and cooling at high pressures to minimize effect of nonhydrostatic stress on the measurements. A linear fit to the high P and T data set yields the elastic bulk and shear moduli [K{sub S} = 175 (2) GPa; G = 91 (1) GPa] and their pressure and temperature derivatives [K{prime}{sub S}=3.9{+}0.3; G{prime} = 1.7 {+} 0.2 and ({partial_derivative}K{sub S}/{partial_derivative}T){sub P} = 18 (2) MPa/K; ({partial_derivative}G/{partial_derivative}T){sub P} = 10 (1) MPa/K]. In a separate analysis, the pressurevolumetemperature data collected during these acoustic experiments were fit to a high temperature BirchMurnaghan (HTBM) equation [with K{prime} fixed at 3.9] and to each isothermal PVT data yielding ({partial_derivative}K{sub T}/{partial_derivative}T){sub P} = 22 (2) MPa/K and ({partial_derivative}K{sub T}/{partial_derivative}T){sub P} = 20 (5) MPa/K, respectively. Comparison of Py{sub 100} data with those other PyMj compositions indicates that the thermo elasticmore »
 Authors:
 Publication Date:
 Research Org.:
 Brookhaven National Laboratory (BNL) National Synchrotron Light Source
 Sponsoring Org.:
 Doe  Office Of Science
 OSTI Identifier:
 914167
 Report Number(s):
 BNL787352007JA
Journal ID: ISSN 00319201; PEPIAM; TRN: US0801589
 DOE Contract Number:
 DEAC0298CH10886
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Phys. Earth Planet. Interiors; Journal Volume: 155; Journal Issue: 34
 Country of Publication:
 United States
 Language:
 English
 Subject:
 43 PARTICLE ACCELERATORS; ACOUSTICS; ELASTICITY; GARNETS; HEATING; INTERFEROMETRY; SHEAR; SYNCHROTRONS; ULTRASONIC WAVES; XRAY DIFFRACTION; national synchrotron light source
Citation Formats
Gwanmesia,G., Zhang, J., Darling, K., Kung, J., Li, B., Wang, L., Neuville, D., and Liebermann, R.. Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000 degrees C. United States: N. p., 2006.
Web. doi:10.1016/j.pepi.2005.10.008.
Gwanmesia,G., Zhang, J., Darling, K., Kung, J., Li, B., Wang, L., Neuville, D., & Liebermann, R.. Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000 degrees C. United States. doi:10.1016/j.pepi.2005.10.008.
Gwanmesia,G., Zhang, J., Darling, K., Kung, J., Li, B., Wang, L., Neuville, D., and Liebermann, R.. Sun .
"Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000 degrees C". United States.
doi:10.1016/j.pepi.2005.10.008.
@article{osti_914167,
title = {Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000 degrees C},
author = {Gwanmesia,G. and Zhang, J. and Darling, K. and Kung, J. and Li, B. and Wang, L. and Neuville, D. and Liebermann, R.},
abstractNote = {Acoustic wave velocities for synthetic polycrystalline pyrope (Mg{sub 3}Al{sub 2}Si{sub 3}O{sub 12}) were measured to 9 GPa and temperatures up to 1000 degrees C by ultrasonic interferometry combined with energydispersive synchrotron Xray diffraction in a cubicanvil DIAtype apparatus (SAM85). Specimen lengths at high pressures (P) and temperatures (T) are directly measured by Xradiographic methods. Elastic wave travel times and Xray diffraction data were collected after heating and cooling at high pressures to minimize effect of nonhydrostatic stress on the measurements. A linear fit to the high P and T data set yields the elastic bulk and shear moduli [K{sub S} = 175 (2) GPa; G = 91 (1) GPa] and their pressure and temperature derivatives [K{prime}{sub S}=3.9{+}0.3; G{prime} = 1.7 {+} 0.2 and ({partial_derivative}K{sub S}/{partial_derivative}T){sub P} = 18 (2) MPa/K; ({partial_derivative}G/{partial_derivative}T){sub P} = 10 (1) MPa/K]. In a separate analysis, the pressurevolumetemperature data collected during these acoustic experiments were fit to a high temperature BirchMurnaghan (HTBM) equation [with K{prime} fixed at 3.9] and to each isothermal PVT data yielding ({partial_derivative}K{sub T}/{partial_derivative}T){sub P} = 22 (2) MPa/K and ({partial_derivative}K{sub T}/{partial_derivative}T){sub P} = 20 (5) MPa/K, respectively. Comparison of Py{sub 100} data with those other PyMj compositions indicates that the thermo elastic properties are insensitive to majorite content in the garnet along the pyropemajorite join.},
doi = {10.1016/j.pepi.2005.10.008},
journal = {Phys. Earth Planet. Interiors},
number = 34,
volume = 155,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Acoustic wave velocities for synthetic polycrystalline pyrope (Mg3Al2Si3O12) were measured to 9 GPa and temperatures up to 1000 C by ultrasonic interferometry combined with energydispersive synchrotron Xray diffraction in a cubicanvil DIAtype apparatus (SAM85). Specimen lengths at high pressures (P) and temperatures (T) are directly measured by Xradiographic methods. Elastic wave travel times and Xray diffraction data were collected after heating and cooling at high pressures to minimize effect of nonhydrostatic stress on the measurements. A linear fit to the high P and T data set yields the elastic bulk and shear moduli [KS = 175 (2) GPa; G =more »

Magnesium grain boundary diffusion in forsterite aggregates at 1000{degrees}1300{degrees}C and 0.1 MPa to 10 GPa
Magnesium grain boundary diffusion rates in forsterite aggregates have been experimentally determined from 1000{degrees} to 1300{degrees}C and 0.1 MPa to 10 GPa. The samples are finegrained (mean linear intercept of 4.3 {mu}m) hotpressed aggregates. The technique employs a {sup 26}Mgenriched surface layer and depth profiling using an ion microprobe. Values of the product of the grain boundary diffusion coefficient (D{prime}) and the effective grain boundary width ({delta}) were calculated using appropriate analytical solutions to the grain boundary diffusion equation of Whipple. The Arrhenius parameters for the 0.1 MPa data for samples annealed in H{sub 2}+CO{sub 2} and CO+CO{sub 2} gasmore »