R3: High-pressure science and deep Earth's material

[R3-09] Dislocation creep of dry orthopyroxene aggregates under high P-T conditions

*Yumiko Tsubokawa¹, Tomohiro Ohuchi¹, Yuji Higo², Yoshinori Tange², Tetsuo Irifune¹ (1. Ehime Uni. GRC, 2. JASRI)

Keywords:Orthopyroxene, Deformation experiment, Dislocation creep, Upper mantle

To determine the flow-law parameters for dislocation creep of orthoenstatite, deformation experiments of dry orthoenstatite aggregates were conducted at high temperatures and high pressures using a D-DIA apparatus combined with synchrotron X-ray radiation. Orthoenstatite indicate dislocation creep with a stress exponent of ~2.8. Burgers vector and slip planes identified by TEM are comparable to those for its two main slip systems of orthoenstatite. Viscosity of dry orthoenstatite is significantly lower than that of dry olivine under lithospheric conditions.