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    Structural Geology   Isotope Geochemistry   Sedimentology   Petrology and Volcanology 
    Paleobiology   Earth observation   Earth Material Science   Geochemistry     

 

                 
 
 
 
 
  Structural Geology Lab. : Structural geology and tectonics of faults and shear zones (This Laboratory will be closed on Mar. 2025 due to the retirement of Prof. Takagi.)
   
 
 

Prof. Hideo Takagi

Dr. Sc. (Nagoya Univ.)

Research Activities

 

 The tectonic evolution of the Japanese Islands, which are located along the convergent Pacific plate boundary, is being determined through the kinematic analysis of its shear zones. The major focus of research in our laboratory is to clarify the strain and kinematic processes, the deformation conditions and deformation history of fault rocks from both the brittle and ductile regimes, at various depths from the uppermost mantle to crustal and surface conditions. Research areas extend from Hokkaido to Kyushu, and also include the Korean Peninsula, the Yunnan area of China and the Himalayas (Nepal). Reconstructions of exotic terranes, such as the Paleo-Ryoke Terrane outcropping between the Sambagawa and Ryoke Belts along the MTL is another major project which relates to the tectonic evolution of Japanese Islands.
 We utilise various research methods which not only include precise field mapping and the collection of oriented rock samples to determine structural elements, but also laboratory work using BSE image and chemical analyses of minerals by EPMA, XRD analysis, observation of substructures using the electron microscope, observation of healed microcracks via cathode luminescence, and the measurement of magnetic susceptibility and isotopic dating.

マイクロクラック

Cathodoluminescence image showing healed microcracks penetrating the Nojima Granodiorite in the Ryoke Belt, Awaji Island.
Blue: K-feldspar, dark purple: quartz, yellow green: plagioclase. Dark part in the plagioclase is amphibole.
Dark veins penetrating K-feldspar are healed microcracks filled with K-feldspar.
 
   
   

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  Isotope Geochemistry (Earth and Palanetary Science) Lab.: Petrology and isotope geochemistry of rocks in diverse geologic settings (This Laboratory will be closed on Mar. 2025 due to the retirement of Prof. Fagan.)
   
 
 

Prof. Timothy J. Fagan

Ph. D. (Univ. California, Davis)

Research Activities

 I use the tools of petrology and isotope geochemistry to understand the formation and alteration of rocks in diverse geologic settings, including terrestrial metamorphic belts, lunar igneous systems, asteroids and the solar nebula (the cloud of dust and gas that surrounded the sun during earliest stages of our solar system).  Most of my recent work is on meteorites, and makes use of Al, Mg isotopes to determine the timing of alteration and O isotopes to assess the evolution of distinct oxygen reservoirs that existed in the solar nebula.

 

Allende隕石 Efremovkaコンドライト
Allende meteorite [detail]



 
Efremovka chondrite
elemental map [detail]


 
 
   
   

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  Sedimentology Lab. : Paleoenvironmental analysis using geochemical proxies in sedimentary rocks.
   
 
 

Prof. Tohru Ohta

Dr. Sc. (Waseda Univ.)

Research Activities

 

 Sedimentary rocks record physico-chemical conditions of the Earth’s past surface environment. Therefore, analyses of sedimentary structures and geochemistry of clastic rocks enable unraveling the environmental changes of the past Earth. By analyzing such records, we tackle to reveal the sedimentary environment and paleoclimate of the Japanese Islands, and further to assess evolutional histories of the Eastern Asian region. The main analytical methods employed in our laboratory include XRF, XRD, EPMA, CL and ICP-AES analysis as well as basic geological field researches.


 
Climbing dunes within the volcanic surge deposits. The presence of climbing dune indicates that both sediment supply and velocity were high during the time of volcanic eruption (Jeju, Korea).
 
   
   

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  Petrology and Volcanology Lab.: Magmatic processes in the shallow crust, and volcanic eruptions.
   
 
 

Prof. Yuki Suzuki

Ph. D. (Univ. of Tokyo)

Research Activities

 

 

 Japan is one of the most famous volcanic countries in the world. Volcanoes fascinate people with their beautiful landscapes and dynamic eruptions and provide benefits such as hot springs and mineral deposits, but they sometimes cause major disasters. Therefore, research on volcanoes is carried out with an awareness of its application to disaster prevention and mitigation. What makes our research laboratory unique compared to other laboratories is that our main research targets are young geological bodies (volcanic bodies) formed since hundreds of thousands of years ago, and ongoing geological phenomena (eruptions) are also included in the research. The time scale of these phenomena is short, with typical volcanic lifespans of several hundred thousand years, with volcanic activities lasting a few years, and with single eruptions lasting from several hours to several minutes.
 The eruptive phenomena observed on the earth's surface are diverse in terms of scale, style, and duration, etc., and it changes even in a single volcanic activity or in the life of a volcano. In order to explore the underlying mechanism, it is essential to clarify the structure of the underground magma supply system and the magma process. The volcanic rock formed by magma erupting onto the surface and rapid cooling have records of the history of magma generation, evolution in magma chambers, and migration of magma to the surface at the time of eruption, along with information on their time scales. The main theme of our laboratory is to decipher these volcanic rocks, "letters from underground," and to understand the mechanisms of diverse eruptive phenomena, eruption triggering processes, and the development history of volcanoes.
 In addition to the petrological methods, we also value the methods of volcanic geology. The layers of geological strata and lava flows left behind by each eruption provide clues to the temporal change of past volcanic activities (eruption style and scale) and the eruption history of a volcano after the birth. In other words, basic data on volcanic geology are essential for conducting meaningful petrological studies. It is believed that each volcano has own characteristics in style of volcanic activity, so exploring the past eruptions is extremely important for predicting the characteristics of future eruptions.
 



Eruption at Showa crater of Sakurajima volcano (July, 2013) .  


The earliest erupted magma in the 2011, Shinmoe-dake eruption
(a fragment in Jan 19 ash).

 
   
   

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  Paleobiology Lab.: Evolutionary paleobiology and its interactions with Earth’s climate in the greenhouse Earth.
 
 
 

Prof. Kazuyoshi Moriya

Ph. D. (Univ. of Tokyo)

Research Activities

 

 The Earth has repeatedly experienced the greenhouse, icehouse, or snowball intervals within its 4.6 billion years history. The climatic oscillation shows significant variety in tempo and magnitude, which is controlled by the external forcing and internal feedbacks of the Earth’s climate system. Since approximately 35 million yeas ago, the Earth has developed continental icesheets, and we now live in the icehouse world. However, the greenhouse interval without any continental icesheet had been predominant in the long Earth’s history.
 Especially, the Cretaceous and early Paleogene (app. 150 to 35 million yeas ago) have been known as the recent archetypal greenhouse interval. In this unique environment, many distinctive faunae and florae had been well diversified. In our laboratory, we investigate thermal structure and circulation of the greenhouse ocean and paleoecology of the molluscs (e.g. ammonoids) and calcareous microfossils (e.g. foraminifers) in this interval. We, then, discuss evolutional history of these animals and global climate change.
 We utilize geochemical analyses of fossil materials in addition to traditional methods, such as field observations and the morphometry of fossils. Stable isotope geochemistry and organic biomarker analyses are especially important to understand the seawater temperature, and habitat and growth rate of ancient animals. With using these methods, we discuss many events having variety of temporal and spatial variation, from the tectonic and orbital scale paleoclimate to the life history of a single animal, and elucidate the interactions of paleobiodiversity and evolution with the global paleoenvironmental shifts.


 

The ammonite pavement in the lower Jurassic Blue Lias in Lyme Regis.


 

Belemunitella americana from the Pee Dee Formation, South Carolina, USA. The international reference standard for stable carbon and oxygen isotopes, PDB, was made from the same species of belemnite fossils from the Pee Dee Formation.

 
   
   

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  Satellite Geodesy Lab.: Geodynamics revealed by artificial satellite observations.
 
 
 

Lecturer. Yusaku Tanaka

Ph. D. (Hokkaido Univ.)

Research Activities

 

 "What should we understand the earth is like?" Humans have been facing this question for a long time. Ancient people thought that the earth was flat. Around the 6th century B.C., however, they came to think that the earth was a sphere. When a ship appeared from beyond the horizon, the top of the ship would first be visible, and then the entire would gradually appear. The shape of the earth would be estimated based on such observations.
 The study of the shape of the earth (and also other planets, asteroids, or satellites in the solar system), including shape, rotation, gravity, natural environment, and those time variabilities based on observations is called "geodesy" in the modern academic world. Geodesy using space technology is called "space geodesy," and especially when using artificial satellite data, it is called "satellite geodesy".
 This laboratory is mainly engaged in satellite geodesy. We use artificial satellite data to investigate the shape, rotation, gravity, and natural environment of the earth and those time variabilities. Artificial satellites observes some physical quantities on the earth, such as positions on the ground, temperature, gravity, and so on, and data analysis is mainly based on statistics. So, statistical analysis of some terrestrial physical quantities observed by artificial satellites characterizes our researches.
 Here is an interesting example. Two figures shown below indicate the results of the analysis of gravity data around Japan observed by satellite gravimetry. These results are based on principal component analysis. If you do not know the details, you can see that the gravity around Japan has been changing co- and post-seismically related to the 2011 off the Pacific coast of Tohoku earthquake. In Figure 1, you can see the post-seismic gravity changes, and in Figure 2, you can see the coseismic gravity changes. The amounts of these changes are so small that humans cannot sense them and they do not affect our daily lives.

Figure 1:First principle component (60.1%) of the gravity changes.

Figure 2:Second principle component (23.5%) of the gravity changes.

 
   
   

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  Earth Materials Science Lab.: Petrology of convergent plate margins.
   
 
 

Assoc. Prof. Tomoki Taguchi

Ph. D. (Nagoya Univ.)

Research Activities

 

 I specialize in metamorphic petrology with a particular research focus on the petrogenesis and exhumation process of high-pressure type metamorphic rocks such as eclogites. The strength of our research group lies in combining geological observations with quantitative petrological, Raman spectroscopic and mineralogical approaches in metamorphic rocks to understand the geochemical and geodynamic processes at subduction zones from the mineral’s nanometer scale to the plate tectonic scale. Principally we have performed laboratory-based investigations on metamorphic rocks from the southwest Japan (Sanbagawa belt), eastern China (Sulu UHP terrane), and others.  


Eclogite-facies bodies from the Sanbagawa belt of southwest Japan.

 
   
   

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  Geochemistry Lab.: Clarifying the Earth's interior and evolution via experimental approaches combined with high-pressure apparatuses and chemical analyses.
 
 
 

Assoc. Prof. Riko Iizuka-Oku

Ph. D. (Univ. of Tokyo)

Research Activities

 

 We humans have only reached the depth of a thin layer from the Earth's surface and still do not fully understand the Earth's interior better than other planets. How can we study the interior of our planet? In our laboratory, we conduct high-pressure experiments using various high-pressure apparatuses to reproduce high-pressure and high-temperature conditions equivalent to the deep Earth (crust, mantle, and core). The main goal is exploring phenomena occurring in the unreached depths and elucidating the inner structure and evolution of the Earth and other terrestrial planets.
 We experimentally investigate changes in the crystal structures and physical properties, and chemical reactions of analogue materials (such as minerals and metals) in the Earth's and planetary interiors under high pressure and high temperature conditions (in the range of ~GPa and several thousand Kelvin). Using in-situ observations via multi quantum beams (synchrotron X-ray and pulsed neutron) and spectroscopy methods (Raman and infrared absorption) combined with chemical analyses of recovered samples, we are especially focusing on the behavior of water (hydrogen) transported to the deep Earth and noble gases that are depleted in the Earth's interior. It is essential to integrate various fields beyond geochemistry for unveiling the Earth's mystery, we are actively involved in the collaborative research working with other universities and research institutes.


Figure 1:Diamond anvil cell (DAC) and silicate sample loaded into its chamber.


Figure 2:Setup for high-pressure and high-temperature neutron experiments and the result of elemental mapping of the recovered sample.

 
   
   

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