Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

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

Wed. May 23, 2018 9:00 AM - 10:30 AM International Conference Room (IC) (2F International Conference Hall, 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), Chairperson:Kawai Kenji, Iizuka Riko

9:30 AM - 9:45 AM

[SIT22-15] Effects of iron on the lattice thermal conductivity of lower mantle minerals evaluated by Ab initio anharmonic lattice dynamics simulations

*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, Solid solution effects of iron, Ab initio calculation

Determination of lattice thermal conductivity (κlat) of lower mantle (LM) minerals is a key to understanding the dynamics and evolution of the earth’s deep interior. Some recent experimental studies have shown that κlat of MgO and MgSiO3 are substantially reduced by Fe incorporation (Manthilake et al., 2012; Goncharov et al., 2015; Ohta et al., 2017; Hsieh et al., 2017); Okuda et al. (2017) reported very weak effects on MgSiO3 at lowermost mantle pressure. So, experimental results are still largely scattered and effects on Fe in κlat remains unclear. We recently established an ab initio technique to compute κlat of Fe-free systems 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, the technique is extended further to Fe-bearing systems, (Mg,Fe)SiO3 bridgmanite (Brg) and (Mg,Fe)O ferropericlase (FP), combined with the internally consistent DFT+U technique (Wang et al., 2015). Calculations demonstrate strong solid solution effects in both Brg and FP. The effects of Fe are found to be caused mainly by the substantial changes in harmonic properties.