広島大学大学院理学研究科 地球惑星システム学専攻

Research Groups

Earth and Planetary Material Science

The time and space scales of many geological phenomena are beyond those of history and access of mankind. Therefore, we need to study natural rocks and minerals which preserve information of the Earth activities, to understand what happened in past, and to predict geological future events. Members of this group study the natural rocks and minerals using cutting edge research tools such as a sensitive high resolution ion microprobe, X-ray fluorescence/Raman spectrometers, transmission/scanning electron microscopes, X-ray diffractometer and others, in addition to field survey. Our main topics include 1) evolution of continental crusts, 2) rock flow mechanism, 3) process of fault motion, 4) formation process of ore, 5) rock-fluid interaction and 6) crystallographic characteristics of minerals and their applications.

  • Tectonics of Japanese Island and East Asia
  • Precambrian plate tectonics
  • Rock rheology (fracture, plastic deformation)
  • Ore formation process
  • Rock-fluid interaction
  • Crystal chemistry of minerals

ANDO, Jun-ichi (Professor)
DAS, Kaushik (Associate Professor)
HAYASAKA, Yasutaka (Associate Professor)
                                (Special Appointment)
HOSHINO, Ken-ichi
                         (Visiting Associate Professor)
OHKAWA, Makio (Assistant Professor)
SARKAR, D. P. (Assistant Professor)

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    Anadir River from mantle peridotite (ophiolite) in the far northeast Siberia, Russia (field survey in August, 2007)

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    Deformed gneiss in India (field survey in 2010)

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    Thin section of upper-mantle rock (microscopic image under cross-polarized light). Inset: dislocations in olivine (transmission electron microscopic image).

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    Ilmenite lamellae in magnetite in Yamaguchi Prefecture, Japan (backscattered electron image by scanning electron microscopy)

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    Crystal structure of mayenite (empirical chemical formula: Ca12Al14O33)

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Earth and Planetary Physics

Present internal structures of the Earth and planets are the results of long-term deformation and fractionation of internal component materials since their births. To study internal structure leads us to know internal material properties and transport mechanisms. And, conversely, to study material properties and transport mechanisms takes us into understanding how present internal structures were created. In this group, we study internal structures, material properties and their transport mechanisms in the Earth and other planets from analyses of seismic waves, friction experiments, high-temperature and high-pressure experiments, and numerical simulations.

  • Slow earthquakes
  • Free oscillations of the Earth
  • Structure and properties of the Earth's interior
  • Fault dynamics and earthquake generation
  • Subsurface fluid migration
  • Deep magma
  • Mantle convection

INOUE, Toru (Professor)
KATAYAMA, Ikuo (Professor)
SUDA, Naoki (Professor)
KAWAZOE, Takaaki (Associate Professor)
SATO, Tomoko (Associate Professor)
KAKIZAWA, Sho (Assistant Professor)
NAKAKUKI, Tomoeki (Assistant Professor)

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    Field survey on serpentinite body in Nagasaki Prefecture, Kyushu island, Japan

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    High-temperature, high-pressure, fluid-flow, gas-medium deformation apparatus

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    Time variation in hypocenter distribution of tremors in the western Shikoku region, Japan (symbol color denotes time on a day scale)

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    Mantle-dynamics simulation of stagnation of slab (former oceanic plate) around the mantle transition zone (~410-660 km depth)

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    Deep mantle minerals synthesized by experiments at high pressure and high temperature (except olivine)

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Earth and Planetary Chemistry

Earth and Planetary Chemistry group is working on cosmochemistry for exterritorial materials (meteorite and cosmic dust), geochemistry for magma dynamics, chemical evolution experiments for biochemical precursor, experimental paleontology for fossil, sedimentary rock, and microbe to understand the evolution for the solar system, the Earth, and life for 4.6 Ga. We use a Thermal Ionization Mass Spectrometer (TIMS), Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), pyrolysis Gas Chromatography-Mass spectrometer (GCMS), electron microscope (e.g., SEM, TEM, EDS, and EBSD), and Synchrotron Radiation (e.g., XRD and STXM) to achieve our goal.

  • Magma geochemistry
  • Astrobiology
  • Analysis of cosmic dusts
  • Shock events recorded in shocked meteorites
  • Water-rock interaction on the Mars
  • Geomicrobiology

SHIBATA, Tomoyuki (Professor)
YABUTA, Hikaru (Professor)
MIYAHARA, Masaaki (Associate Professor)
SHIRAISHI, Fumito (Associate Professor)
CHAKRABORTI, T. M. (Assistant Professor)
KOIKE, Mizuho (Assistant Professor)
OTTO, Katharina A. (Assistant Professor)
                             (Special Appointment)
YOSHIKAWA, Masako (Researcher)

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    Stromatolite in the Western Australia

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    Field survey at the Sanbe hot spring in Shimane Prefecture, Japan

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    Shock-induced glass (blue) in plagioclase (red) caused by meteorite impact

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    High-pressure mineral (stishovite, SiO2) in shocked meteorite (transmission electron microscopic image)

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    Mass spectrometer

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Integrated Earth and Ocean Sciences (Institute for Interdisciplinary Science)

We study issues of geosciences, such as earthquakes and global environmental changes, by analyzing drill core samples and related materials recovered from a wide range of locations from continents to deep-sea floor with an interdisciplinary approach.

  • Geochemical cycle and enviromental change recorded in sediments and rocks
  • Microbiological and geochemical exploration of subseafloor biosphere
  • Mechanics of earthquake and faulting
  • Geomicrobiology
  • Development of analytical techniques of isotopes and trace elements in core samples

ISHIKAWA, Tsuyoshi (Visiting Professor)
TOMIOKA, Naotaka (Visiting Professor)
HIROSE, Takehiro (Visiting Professor)
HOSHINO, Tatsuhiko (Visiting Associate Professor)