A research group led by Associate Professor Motohiko Murakami at Graduate School of Science, Tohoku University has successfully Measured the precise elastic wave velocities of SiO2 glass under ultrahigh-Pressure that exceeds 2 million atmospheric pressure, and found that SiO2 glass has become heavier and denser above 1.4 million atmospheric pressures. The research group has examined a densification mechanism of magma (SiO2 glass) under the relevant ultrahigh-pressure conditions to the Earth’s deep interior, and simulated the density relationship of deep magma ocean covered the ancient Earth which occurred about 4 billion years ago. The research results strongly show that a density of magmas became extremely higher under the condition of more than 3,000-kilometer deep into the magma ocean and above 1.4 million atmospheric pressures, and that gravitationally stable and extremely heavy magma stayed deep into the Earth. These findings are expected to constraint the Earth history of the chemical/physical differentiation from the ancient Earth covered by magma ocean, and to contribute to the new development of material synthesis under ultrahigh-pressure.

 The research has been jointly conducted with Professor Jay D. Bass at the faculty of Science, University of Illinois with the aide of a Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science (JSPS), and Tohoku University Global CEO Program “Global Education and Research Center for Earth and Planetary Dynamics.” The research results will be published online in “Physical Review Letters,” a scientific journal issued by American Physical Society soon. The paper’s title is _Spectroscopic evidence for ultrahigh-pressure polymorphism in SiO2._

[Contact]
Associate Professor Motohiko Murakami
Graduate School of Science, Tohoku University
Tel: +81-22-795-5789 (or 6662)
E-mail: motohiko@m.tains.tohoku.ac.jp
URL: http://www.ganko.tohoku.ac.jp/bussei/member/Murakami