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

[R3-03] Shear instability and superplasticity induced by the metastable transformation in mantle olivine: Implications for microstructural evolution and rheology of MTZ slab

*Tomoaki Kubo¹, Rikuto Honda¹, Yuta Goto¹, Masahiro Imamura¹, Masaaki Miyahara², Yuji Higo³, Akio Suzuki⁴ (1. Kyushu Univ., 2. Hiroshima Univ., 3. JASRI, 4. Tohoku Univ.)

Keywords:olivine-spinel transformation, post-spinel transformation, deformation, synchrotron radiation

The non-equilibrium olivine-spinel and post-spinel transformation has been proposed to trigger deep-focus earthquakes and superplasticity. However, direct experimental study at mantle transition zone conditions have been limitted. We conducted deformation and transformation experiments at MTZ pressures using D-111 type apparatuses to address this issue. We will discuss microstructural evolution and rheology of MTZ slab based on the obtained results combined with some results on polycrystalline kinetics.