Structure measurement of hydrous magma using neutron diffraction: Understanding of pressure dependences of hydrogen position

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18797
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Earth and planetary science and related fields
• Research Institution: Tohoku University
• Principal Investigator: Sakamaki Tatsuya 東北大学, 理学研究科, 助教 (30630769)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: マグマ / 水 / 水素 / 高圧 / 高温

Outline of Final Research Achievements

We succeeded in measuring the structure of hydrous magma at high pressure and temperature using X-ray and neutron diffraction techniques. One of the most important findings in this study is the pressure-induced anomalous change in the ordering of network structure: the periodicity of network structure of the hydrous magma extends up to 4 GPa and starts to shrink at much higher pressure. Since the structure of magma changes drastically around 4 GPa (120 km in depth), the behavior of the magma can be also varied. We can obtain a significant knowledge for understanding the magma behavior in the interior of the Earth.

Free Research Field

地球科学

Academic Significance and Societal Importance of the Research Achievements

マグマは、火山や中央海嶺から地表へ噴出するものに加え、地下数百～数千kmの地球深部に局所的に存在するということが、主に地球物理学的探査から示唆されてきた。このような地球深部マグマの挙動を、その構造を研究することで解明することに成功した。本研究成果は、我が国とも関わり合いの深い火成活動を中心としたマグマに関連する諸現象を理解するための新たな基礎的知見をもたらしたという重大な意義を持つ。