5:15 PM - 5:30 PM
[SIT04-17] Preliminary deformation experiments for in-situ stress-strain measurements of bridgmanite
Keywords:Bridgmanite, In-situ measurements, deformation experiments, The Earth's lower mantle
In-situ uniaxial deformation experiments were conducted using MADONNA, which is D-DIA apparatus, as Kawai-type apparatus at SPring-8 BL04B1. Experimental conditions are 27.3 GPa, 1473 K estimated by equation of state on bridgmanite (Katsura et al., 2009). WC anvils with slit or corn (5o) to take tomography and 2D X-ray diffraction, was used along X-ray path. Two-dimensional X?ray diffraction patterns were taken for 300 s using CCD detector. To calculate the stress magnitude from the X?ray diffraction data, we used a model of stress-lattice strain relationship (Singh et al. 1998),
dhkl(ψ)= d0hkl [1+(1-3cos2ψ) σ/6 Ghkl] (1)
where dhkl is the d-spacing measured as a function of azimuth angle ψ, d0hkl is the d-spacing under the hydrostatic pressure, Ghkl is the appropriate shear modulus for a given hkl, and σ is the uniaxial stress. Pressure and stress were estimated using bridgmanite (111) diffraction peak at deformation experiments. X?ray radiographies of the strain markers was taken using an imaging system composed of a YAG crystal and a CCD camera with an exposure time of 10 s.
Uniaxial tension stress and strain of Mg-Pv at 27.3 GPa, 1473 K were estimated as ~1.3 GPa and ~4 % during doformation by differential ram. We confirmed deformation experiments at the lower mantle pressure conditions can be conducted by WC anvils. We will perform additional deformation experiments with large strain.