下部マントルにおけるブリッジマナイトのレオロジー研究

抄録

Knowledge of rheological properties of bridgmanite, which is the most abundant mineral at the lower mantle, is one of the most important parameters to understand mantle dynamics. We developed deformation experimental technique up to the top of lower mantle conditions using D-DIA apparatus as Kawai-type (6-8 type) Press. Using this technique, crystallographic-preferred-orientation (CPO) of bridgmanite induced by shear deformation was determined. The seismic shear wave anisotropy observed around subduction zone at the lower mantle, can be explained in terms of the CPO of bridgmanite with mantle flow parallel to the direction of subduction zone. We also succeeded to measure the viscosity of bridgmanite in dislocation creep regime by in-situ deformation experiments.