11:30 AM - 11:45 AM
[SIT21-10] Measurements of high pressure-temperature thermal conductivity of the Earth’s lower mantle minerals in a laser-heated diamond anvil cell
Keywords:Thermal conductivity, Lower mantle, High P-T experiment
We recently developed a new instrument to measure the thermal diffusivity (and thus thermal conductivity) of sample in-situat high pressure and temperature based on the combination of the TR method and the LHDAC system. We use a double-sided high-power CW laser heating technique to generate stable high temperature conditions of sample in a DAC. A pulsed pump laser and a CW probe laser are also irradiated to the sample to determine heat diffusion time through the sample via the thermoreflectance phenomena. Details of the thermoreflectance technique in a DAC may be found in our previous studies . Using the developed method, we measured the thermal conductivity of the main minerals in the Earth’s lower mantle, MgO periclase, MgSiO3bridgmanite, post-perovskite and CaSiO3perovskitein-situat high pressures and high temperatures. These are the first experimental demonstrations of thermal conductivity of the lower mantle minerals at the conditions below the mid-part of the Earth’s lower mantle. The new thermal conductivity measurement system will shed light on the controversial thermal transport properties of the Earth’s deep interior .
References: Hsieh, W.-P. et al., Phys. Rev. B, 80, 180302 (2009). Yagi, T. et al., Meas. Sci. Technol., 22, 024011 (2011).  Okuda, Y. et al., Earth Planet. Sci. Lett., 474, 25–31 (2017).  Kavner, A. and Rainey, E.S.G., Deep Earth: Physics and Chemistry of the Lower Mantle and Core, 31–42 (2016).