Thermal conductivity and evolution of the Earth's and Mars' cores

Abstract

Precise determinations of the thermal conductivity of Fe alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth and other terrestrial bodies. While it can be directly measured, the thermal conductivity of metal is obtained from its electrical resistivity via Wiedemann–Franz law. Here we review recent measurements of the electrical resistivity of Fe alloys in a diamond-anvil cell, considering the resistivity of Fe, impurity resistivity, and the resistivity saturation effect, as well as the direct measurements and calculations of their thermal conductivity (or diffusivity). We also discuss implications of the high thermal conductivity of the Earth's and Martian cores for their thermal and compositional evolutions.