Presentation Information
[SMP31-P14]Deformation experiments on olivine aggregate with pre-existing fabric
*Kanata Takada1, Takehiko Hiraga1, Saya Yoshimatsu 1 (1.Earthquake Research Institute, University of Tokyo)
Keywords:
olivine,anisotropy,diffusion creep
In this study, we conducted pure shear and uniaxial deformation experiments on the aggregate with pre-existing A-type fabric: (i) olivine a-and b-axes parallel to directions of extension and compression, respectively, (ii) b-axes parallel to a directions of compression and a- and c-axes inclined at 45 degree to the tensile direction, (iii) b-planes oriented in the direction of the maximum shear stress with a-and c-axes axes oriented at ~45 degree against the direction of the maximum shear stress, and (iv) compressed uniaxially with b-plane oriented perpendicular to the compression direction. We found that CPO becomes insensitive with strain at the strain of >~0.8 with low CPO strength. Such CPO should correspond to steady-state CPO during diffusion creep. We observed grain rotation based on the change in the directions of CPO during diffusion-creep. So far, we can explain these observations based on preferential (easy) grain-boundary-sliding (GBS) on b-plane boundaries in the direction a-axis (e.g., Kim et al., 2020).