| Co-Investigator(Kenkyū-buntansha) |
MATSUI Masanori Kyushu Univ.Faculty of Science Ass.Prof., 理学部, 助教授 (90125097)
HUJINO Kiyoshi Hokkaido Univ.Graduate School Prof., 大学院・理学研究科, 教授 (40116968)
SUENO Shigeo Tsukuba Univ.Earth Science Prof., 地球科学系, 教授 (30110513)
IISHI Kazuaki Yamaguchi Univ.Faculty of Science Prof., 理学部, 教授 (60034716)
AKAOGI Masaki Gakushuin Univ.Faulty of Science Prof., 理学部, 教授 (30126560)
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| Research Abstract |
Conventional thermodynamical phase studies of earth interiors are not enough scientific approaches to comprehend the various geophysical phenomena Dynamical investigations of mantle substances are also significant to understand mantle dynamics such as subjection of slab and tectonic movement. It has been known that earth interiors have many types of structure changes under high pressure and temperature. Many attentions have been paid to the following phase changes ; (1).phase transformation (transition, melt, amorphization) ; (2).decomposition, (exsolution, dissociation, phase separation) ; (3).crystallization, (nucleation, growth, domain growth) ; (4).chemical reaction (solid-solid, solid-molten salt) ; (5).electronic changes, (excitation of electronic, ionic and radical). These transformations tend to maintain their stability in the new circumference and induced by changing the physical and chemical conditions such as pressure, temperature, partial pressure of oxygen, stress field, chemical potential around the substances in the mantle or shell.
In order to elucidate these phase changes, in situ X-ray diffraction studies have been made using diamond anvil (DAC) or multianvil high pressure apparatusinstalled in synchrotron radiation at Photon Factory in National Institute for High Energy Physics. Structure analyzes and physical properties under high pressure and temperature similar to the mantle condition or subjection zone were also investigated.
Compressibility, elastic constant and thermal expansion coefficients of many mantle minerals have been measured. Electric conductivity has also been measure as a function of pressure.
Molecular dynamical calculation simulates the structure and physical properties. Pressure-induced transformation, melting or crystallization from molten salt have been simulated under extreme conditions.
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