Japan Geoscience Union Meeting 2018

Presentation information

[EE] Poster

S (Solid Earth Sciences) » S-IT Science of the Earth's Interior & Tectonophysics

[S-IT22] Interaction and Coevolution of the Core and Mantle in the Earth and Planets

Tue. May 22, 2018 10:45 AM - 12:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Tsuyoshi Iizuka(University of Tokyo), Hidetoshi Shibuya(Department of Earth and Environmental Sciences, Faculty of Advanced Science and Technology, Kumamoto University), Taku Tsuchiya(愛媛大学地球深部ダイナミクス研究センター, 共同), Kenji Ohta(Department of Earth and Planetary Sciences, Tokyo Institute of Technology)

[SIT22-P17] Ab initio lattice thermal conductivity of MgSiO3 post-perovskite

*Haruhiko Dekura1, Taku Tsuchiya1,2 (1.Geodynamics Research Center, Ehime University, 2.Earth-Life Science Institute, Tokyo Institute of Technology)

Keywords:Lower mantle minerals, Lattice thermal conductivity, Ab initio calculation

Lattice thermal conductivity (κlat) of the lowermost mantle (D'' layer) is one of the key properties controlling the thermal evolution of the Earth and MgSiO3 post-perovskite (PPv) is believed to be the most abundant mineral in this region. Ohta et al. (2012) measured the κlat of PPv but only at 300 K, far from the mantle temperature. On the other hand, the κlat of PPv was computed under lowermost mantle P,T (Haigis et al., 2012; Ammann et al., 2014) but using interatomic model potentials with adjustable parameters. Reported κlat of PPv under the lowermost mantle P,T are inconsistent with each other. We recently established an ab initio technique to compute κlat based on the density-functional theory (DFT) combined with fully solving the phonon Boltzmann transport equation, which was successfully applied to MgO (Dekura and Tsuchiya, 2017). In this study, using this technique, κlat of PPv is calculated under the lowermost mantle condition, and it is found ~20% lower than those reported in the model potential studies. We also find that the κlat of PPv is ~50% larger than that of Brg. This indicates that the lateral variations in the core-mantle boundary heat flux would be enhanced by the Brg-PPv phase transition. Effects of anisotropy in the κlat of PPv on the heat flux will also be discussed.