High-Pressure, -Temperature Deformation Experiments Using the in situ X-Ray Facility at X17B2 at NSLS

Shun-Ichiro Karato, Yale University

We have conducted a series of deformation experiments on minerals in the Earth’s deep interior under high-pressure and temperature conditions. The experimental studies involve three components:
(1) development of a new type of deformation apparatus
(2) applications of x-ray facilities at X-17B at NSLS
(3) the development of a theoretical model to interpret x-ray diffraction data.

In 2004, we started this series of work in collaboration with Don Weidner’s group at Stony Brook University who has developed all the x-ray facilities needed for this work. In this study, we apply differential stress to a sample under high-pressure and temperature using a newly designed apparatus (RDA (rotational Drickamer apparatus)), and measure stress and strain using in-situ x-ray facility at NSLS. The new theory is used to interpret x-ray diffraction data in terms of stress level and its distribution.

The maximum pressure and temperature range explored so far is P to ~22 GPa and T to ~2200 K. Using this technique, we have determined (1) the pressure dependence of creep strength of water-free olivine to P~10 GPa and T~1900 K, (2) obtained the creep strength data for wadsleyite and ringwoodite (to P~22 GPa, T~2200 K). These results help understand the stability of the deep continental roots, the energy dissipation associated with deep slab deformation.

This research was partially supported by COMPRES, EAR 10-43050

Kawazoe, T., S. Karato, J. Ando, Z. Jing, K. Otsuka, and J. W. Hustoft (2010), Shear deformation of polycrystalline wadsleyite up to 2100 K at 14–17 GPa using a rotational Drickamer apparatus (RDA), J. Geophys. Res., 115, B08208, doi:10.1029/2009JB007096.

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