Japan Geoscience Union Meeting 2018

Presentation information

[EE] Poster

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

[S-IT18] Planetary cores: Structure, formation, and evolution

Mon. May 21, 2018 10:45 AM - 12:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Hidenori Terasaki(Graduate School of Science, Osaka University), Eiji Ohtani(Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University), William F McDonough (共同), George Helffrich(Earth-Life Science Institute, Tokyo Institute of Technology)

[SIT18-P01] Sound velocity of liquid Fe-Ni-S-Si at Mercury outer core condition

*Yamada Iori1, Hidenori Terasaki2, Asaka Kamiya1, Keisuke Nishida3, Yuki Shibazaki4, Tatsuya Sakamaki4, Yuji Higo5, Yoshinori Tange5, Tadashi Kondo2 (1.Osaka University, 2.Graduate School of Science, Osaka University, 3.Graduate School of Science, Tokyo University, 4.Graduate School of Science, Tohoku University, 5.Japan Synchrotron Radiation Research Institute)

Keywords:Sound velocity, Mercury, Liquid core

A large Mercury core consists mainly of Fe and Ni and also contains some light elements. The X-ray spectroscopy measurements by the MESSENGER spacecraft indicates that 1-4 wt% S is included on its surface. Based on the partitioning behavior of S and Si between metal and silicate melts, both S and Si can be contained in metal phase when coexisting silicate melt contains 1-4 wt%S, suggesting that both S and Si are likely to be included in the outer core (Chabot et al. 2014). Thus, elastic properties of liquid Fe-Ni-S-Si are important implication to study the interior structures of Mercury and properties of liquid outer core.

In this study, we performed sound velocity measurement of liquid Fe-Ni-S-Si up to 14.8 GPa and 1943 K using multianvil press at BL04B1, SPring-8 facility. The sound velocity was measured using the pulse-echo overlap method. The P-wave velocity increases with pressure. Although the P-wave velocity of liquid Fe-Ni decreases by addition both of S and Si, it likely to increase from the velocity by addition of only S.