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Research Group Division of Earth and Planetary Materials Science


Petrotectonics Research Group

•Professor Tatsuki Tsujimori (Center for Northeast Asian Studies),
specializing in in metamorphic petrology and regional tectonics, with a particular research focus on the petrogenesis and geochemistry of high-pressure metamorphic rocks such as blueschists and eclogites
•Associate Professor Naoto Hirano (Center for Northeast Asian Studies),
specializing in Volcanoes, Basalt, and Ocean floor tectonics
•Assistant Professor Akio Goto (Center for Northeast Asian Studies),
specializing in Rheology on magma, and Physics on eruption phenomena
•Assistant Professor Tsuyoshi Miyamoto (Center for Northeast Asian Studies),
specializing in Volcano formation development history, and Petrology on magma process


Our research group studies earth materials science from the viewpoint of regional geology focused in northeastern Asia. Main objects of our study are ophiolites and volcanoes. Ophiolites are fragments of the ancient oceanic lithosphere that were accreted to the continental margin through subduction processes. They provide a key to elucidating the structure and composition of the oceanic lithosphere as well as the tectonic evolution of orogenic belts and genesis of our mineral resources. Our studies of volcanoes include geological mapping and geochemical analyses of lavas and pyroclastic deposits as well as geophysical measurements and analogue experiments of volcanic eruptions. These studies will clarify the intensity and mechanism of large-scale volcanic eruptions in the past, and contribute to mitigation of volcanic hazards in the future.

(1) Rock geological study of northeast Asian area

(1) Rock geological study of northeast Asian area The northeast Asian area is part of the Pacific Ring of mountain ranges that include the Japan islands. Both areas have many common points from a geological and lithological perspective. To know how the Japan islands were created during the past hundreds of millions of years, it is unavoidable that we study and investigate our neighboring northeast Asian area to study the past geological features as restored, many of which have been already lost in Japan. First, we strive to study ophiolites and greenstones in particular, which are found in places where rocks of the past oceanic crust are exposed on the land area. Next, we understand clearly the geological structure of the northeastern Asian area, including Japan, in addition to the history of the plate movements and mantle plumes activities. Through them all, we would like to deepen our knowledge of how our land has been created. We hope to help develop new resources and reduce disasters in the future as well.

(2) Development process of petit spot volcano and oceanic plate

(2) Development process of petit spot volcano and oceanic plate Such a geological phenomenon as an eruption of a volcano or a huge earthquake happening on the earth results from some rock beds (plates) covering the earth surface moving against one another. To find such a plate movement, we are studying the distribution of and the past activities of volcanoes as well as the magma creation mechanism while making field investigations and conducting examinations on the deep-sea bottom as well. In addition, we are investigating a new type of volcano (petit spot volcano), one of which was found in 2006 off Sanriku area of Japan.