# 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 energy-dispersive synchrotron X-ray diffraction in a cubic-anvil DIA-type apparatus (SAM-85). Specimen lengths at high pressures (P) and temperatures (T) are directly measured by X-radiographic methods. Elastic wave travel times and X-ray diffraction data were collected after heating and cooling at high pressures to minimize effect of non-hydrostatic 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 pressure-volume-temperature data collected during these acoustic experiments were fit to a high temperature Birch-Murnaghan (HTBM) equation [with K{prime} fixed at 3.9] and to each isothermal P-V-T 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 Py-Mj 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):
- BNL-78735-2007-JA

Journal ID: ISSN 0031-9201; PEPIAM; TRN: US0801589

- DOE Contract Number:
- DE-AC02-98CH10886

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Phys. Earth Planet. Interiors; Journal Volume: 155; Journal Issue: 3-4

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; ACOUSTICS; ELASTICITY; GARNETS; HEATING; INTERFEROMETRY; SHEAR; SYNCHROTRONS; ULTRASONIC WAVES; X-RAY 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 energy-dispersive synchrotron X-ray diffraction in a cubic-anvil DIA-type apparatus (SAM-85). Specimen lengths at high pressures (P) and temperatures (T) are directly measured by X-radiographic methods. Elastic wave travel times and X-ray diffraction data were collected after heating and cooling at high pressures to minimize effect of non-hydrostatic 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 pressure-volume-temperature data collected during these acoustic experiments were fit to a high temperature Birch-Murnaghan (HTBM) equation [with K{prime} fixed at 3.9] and to each isothermal P-V-T 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 Py-Mj compositions indicates that the thermo elastic properties are insensitive to majorite content in the garnet along the pyrope-majorite join.},

doi = {10.1016/j.pepi.2005.10.008},

journal = {Phys. Earth Planet. Interiors},

number = 3-4,

volume = 155,

place = {United States},

year = {Sun Jan 01 00:00:00 EST 2006},

month = {Sun Jan 01 00:00:00 EST 2006}

}