Energy dissipation of materials at high pressure and high temperature

We report an experimental method to study the anelastic properties of materials at high pressure and high temperature. The multianvil high pressure deformation device, used to apply a cyclic loading force onto the sample, can reach 15 GPa and 2000 K. A synchrotron x-ray radiation source provides time resolved images of the sample and reference material. The images yield stress and strain as a function of time; stresses are derived from the reference material, and strains from the sample. This method has been tested by applying a sinusoidal stress at megahertz to hertz frequency on a San Carlos olivine specimen at 5 GPa and up to 2000 K. Strain as small as 10(-5) can be resolved. We have obtained experimental results which exhibit resolvable attenuation factor (Q(-1)) and shear modulus (M) at deep Earth conditions. These results are in quantitative agreement with previously reported lower pressure data and suggest that temperature and grain size have dominating effect on these properties.