Effects of pressure on diffusion creep in wet olivine aggregates
نویسندگان
چکیده
We report the results of an experimental study to determine influence pressure on diffusion creep in wet olivine. In order observe at high-pressure conditions laboratory strain rates, we prepared ultra-fine grained (0.22–0.72 μm) olivine aggregates both from San Carlos and oxide mixtures using a solgel technique. All samples contain some water (~1000 ppm wt) presumably due adsorption fine-grained powder samples. used Deformation-DIA (D-DIA) coupled with synchrotron X-ray facility (6-BM-B beamline APS) perform in-situ high (3–10 GPa) deformation experiments temperature range 973–1123 K. The operation our was inferred weak (hkl) dependence lattice strain, much smaller strength compared expected for dislocation creep, estimate stress exponent. Diffusion also confirmed comparison previous lower pressures. assume flow low following form ε˙∝CWrd−mexp−PV∗RT (ε̇: rate, CW: content, d: grain size) r = 0.7–1.0 m 2 or 3, which obtain activation volume (V*) 2.5 +/− 0.6 cm3/mol. This is substantially than that implying plays important role deep upper mantle. Some implications seismic anisotropy are discussed.
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ژورنال
عنوان ژورنال: Physics of the Earth and Planetary Interiors
سال: 2022
ISSN: ['1872-7395', '0031-9201']
DOI: https://doi.org/10.1016/j.pepi.2022.106840