Effect of mass disorder on the lattice thermal conductivity of MgO periclase under pressure.
Thermal conductivity of mantle materials controlling the heat balance and thermal evolution of the Earth remains poorly constrained as the available experimental and theoretical techniques are limited in probing minerals under the relevant conditions. We report measurements of thermal conductivity of MgO at high pressure up to 60 GPa and 300 K via diamond anvil cells using the time-domain thermoreflectance technique. These measurements are complemented by model calculations which take into account the effect of temperature and mass disorder of materials within the Earth. Our model calculations agree with the experimental pressure dependencies at 300 and 2000 K for MgO. Furthermore, they predict substantially smaller pressure dependence for mass disordered materials as the mechanism of scattering changes. The calculated thermal conductivity at the core-mantle boundary is smaller than the majority of previous predictions resulting in an estimated total heat flux of 10.4 TW, which is consistent with modern geomodeling estimates.
Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, USA.
Douglas Allen
DA
Dalton
Wen-Pin
WP
Hsieh
Gregory T
GT
Hohensee
David G
DG
Cahill
Alexander F
AF
Goncharov
D003198:Computer Simulation; D006112:Gravitation; D008277:Magnesium Oxide / Q000737:chemistry*; D008422:Materials Testing; D008903:Minerals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008970:Molecular Weight; D011312:Pressure; D013696:Temperature; D013814:Thermal Conductivity
D008903:Minerals; D008277:Magnesium Oxide