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-P02] Core composition of Mercury estimated from elastic properties of liquid Fe-Ni-alloy

*Hidenori Terasaki1, Attilio Rivoldini2, Yuta Shimoyama1, Keisuke Nishida3, Satoru Urakawa4, Fuyuka Kurokawa1, Yusaku Takubo1, Yuki Shibazaki5, Tatsuya Sakamaki5, Akihiko Machida6, Yuji Higo7, Tadashi Kondo1 (1.Graduate School of Science, Osaka University, 2.Royal observatory of Belgium, 3.Graduate School of Science, The University of Tokyo, 4.Graduate School of Natural science and technology, Okayama University, 5.Graduate School of Science, Tohoku University, 6.QST, 7.JASRI)

Keywords:Mercury, Elastic property, Core

Knowledge about density and elastic properties, such as bulk modulus, of liquid Fe-Ni-alloys at high pressure are important to constrain the interior structure and composition of planetary cores. Mercury's core is relatively large compared to other terrestrial planets and is at least in a partially molten state (Margot et al. 2007). Recent X-ray spectroscopy data suggests that S of 1-4 wt% exists on the surface, indicating possible existence of some amounts of S in the core (e.g., Chabot et al. 2014). In this study, we have measured sound velocity and density of liquid Fe-Ni-S using ultrasonic pulse-echo and X-ray absorption methods combined with multianvil apparatus up to 14 GPa. The obtained sound velocity and bulk modulus significantly decreased with increasing S concentration especially at lower pressures. We asses the effect of the newly obtained elastic properties on the compositions of Mercury's core.