THERMAL-DIFFUSIVITY OF PERICLASE AT HIGH-TEMPERATURES AND HIGH-PRESSURES

Thermal diffusivity of periclase is measured at pressures up to 5 GPa and at temperatures from 400 to 1500 K using a 6-8 type multi-anvil ap paratus by adopting the Angstrom method in a cylindrical geometry. The logarithmic volume derivative of the parameter b, which indicates the rmal resistance by the anharmonicity of the lattice vibration, is (par tial derivative ln b/partial derivative ln V) = 9.9. The lattice therm al diffusivity of magnesiowustite at the top of the lower mantle is es timated to be 5.8 X 10(-6) m(2) s(-1). Thermal conductivity of magnesi owustite in the lower mantle is mostly attributed to the heat transfer by the propagation of lattice wave.