Meeting room "Glova", 4 floor, Integrated Research Building
Abstract
Under the conditions of the Earth's mantle, both diffusion creep and dislocation creep can be the dominant deformation mechanism depending on physical and chemical environments. It is important to understand the dominant deformation mechanism in the mantle. In order to clarify the dominant deformation mechanism in the upper mantle, we have conducted deformation experiments at high-pressure and high-temperature using fine-grained forsterite aggregate. Experiments were carried out using a D-DIA apparatus at PF-AR, High Energy Accelerator Research Institute. The steady state stress-strain rate data taken at "dry" conditions (<50 H/10^6Si) together with data at 0.1 MPa were analyzed using a flow law equation. Based on the analysis, the activation volume (V*dif) for diffusion creep of olivine was determined to be ~9 cm3/mol. Karato and Wu (1993) discussed that diffusion creep is the dominant deformation mechanism below ~200 km depth using assumed value of V*dif = 6 cm3/mol. Present result implies that diffusion creep is predominant only at deeper part of upper mantle.
For inquiry：Taku Tsuchiya TEL:（089）927-8198
E-mail takut@sci.ehime-u.ac.jp
