[S-IT15] Study of the Earth's Deep Interior - Interaction and Coevolution of the Core and Mantle

[SIT15-P01] First-principles study on the thermal transport properties of the subducting slab

*Haruhiko Dekura¹ (1.Geodynamics Research Center, Ehime University)

Keywords:Lower mantle, Thermal transport property, Theory

The temperature structure of the Earth's interior is still one of the most uncertain physical quantities. Since the viscosity is a key parameter controlling the style of the mantle convection and is sensitive to temperature, the temperature profile of the mantle provides a basis for a better understanding of mantle dynamics. The subducting slab is one of the potential sources producing both the temperature and chemical heterogeneities in the deep Earth. The heat transport mechanism by thermal conduction is likely to be dominant in the subducting slab. Therefore, the temperature heterogeneity of the deep mantle induced by the subduction can be better constrained by determining the lattice thermal conductivity (κ) of its constituent minerals. However, precise determinations of the κ under the deep mantle conditions are still challenging, making the heat transport properties of the subducting slab remain unclear. We have recently initiated the first-principles determination of the κ of those minerals based on the density-functional theory for a tighter constraint on the temperature structure. In this presentation, we will report our progress of both harmonic and anharmonic phonon calculations of SiO₂ and CaSiO₃ perovskite necessary to compute κ under the lower mantle conditions.