JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

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

[S-IT23] [EE] Structure and Dynamics of Earth and Planetary Mantles

Mon. May 22, 2017 10:45 AM - 12:15 PM A05 (Tokyo Bay Makuhari Hall)

convener:Takashi Nakagawa(JAMSTEC/MAT), Dapeng Zhao(Department of Geophysics, Tohoku University), Takashi Yoshino(Institute for Planetary Materials, Okayama University), Chairperson:Tomoeki Nakakuki(Hiroshima University), Chairperson:Koichiro Umemoro(Tokyo Institute of Technology)

12:00 PM - 12:15 PM

[SIT23-18] Fate of MgSiO3 post-perovskite in super-Earths

*Koichiro Umemoto1, Renata Wentzcovitch2, Shunqing Wu3, Kai-Ming Ho3, Min Ji3, Cai-Zhuang Wang3 (1.Earth-Life Science Institute, Tokyo Institute of Technology, 2.Columbia Universitity, 3.Iowa State University)

Keywords:MgSiO3 post-perovskite, pressure-induced phase transition, first-principles calculation, terrestrial exoplanets

MgSiO3 post-perovskite (ppv) is the final form of MgSiO3 in the Earth. However, what happens in super-Earths in which pressure and temperature are much higher than those of the Earth’s lower mantle? Understanding of fate of MgSiO3 ppv under ultrahigh pressures is crucial for nature of interiors of super-Earths. Computational studies so far have predicted several pressure-induced dissociations of MgSiO3 in super-Earths. Recent studies agree that MgSiO3 ppv undergoes three-stage dissociations involving MgO, SiO2, Mg2SiO4, and MgSi2O5 [1,2]. Based on these studies, we reinvestigate the high PT phase diagram of MgO-SiO2 system and we propose a new phase transition in MgO-SiO2 system in super-Earths. Clapeyron slope of the new transition and thermodynamic quantities calculated for these phases should provide fundamental information for numerical simulation of mantle dynamics in super-Earths.

[1] S. Q. Wu, M. Ji, C. Z. Wang, M. C. Nguyen, X. Zhao, K. Umemoto, R. M. Wentzcovitch, K. M. Ho, J. Phys. Condensed Matter, 26, 035402 (2014).
[2] H. Niu, A. R. Oganov, X. Q. Chen, and D. Li, Sci. Rep. 5, 18347 (2015).