Motohiro Tsuboi

Major research fields


What is the structure of our living Earth? When was the Earth formed? These questions excite a feeling of our curiosity. The earth is composed of rocks, water and gases. These materials interact dynamically not only on the surface but also in the interior of the earth. Geochemistry is the study to understand these dynamic processes on the earth using chemistry. In our laboratory, we focus on the rocks and minerals. Rocks and minerals record the Earth's history when those were formed. So, rocks and minerals are the "Time Capsule" of the Earth. Our mission is to decode the time capsule letter from the earth. Among many kinds of rock types on the earth, our research target is granite. Granite is a common felsic igneous rock which mainly forms the continental crust of the earth. It mainly contains quartz, plagioclase, mica, amphibole and the small amount of accessory minerals such as zircon and apatite. We can get information of rock-forming environment such as pressure, temperature and the age by analyzing these minerals. The main research instruments we use include a polarizing microscope, X-ray diffraction spectrometer (XRD), X-ray fluorescence spectrometer (XRF) and Fourier transform infrared spectroscopy (FT-IR). Our research contributes not only to basic science but also to applied science such as natural resources and environmental pollution.

Major relevant publications

  1. Tsuboi, M., Asahara, Y. Heterogeneity of initial 87Sr/86Sr ratio within the Kamihara Tonalite, Ryoke belt, southwest Japan: evidence from strontium isotopic study of apatite, Journal of Mineralogical and Petrological Sciences, 104, 226-233 (2009)
  2. Tsuboi, M., The use of apatite as a record of initial 87Sr/86Sr ratios and indicator of magma processes in the Inagawa pluton, Ryoke belt, Japan, Chemical Geology, 221, 157-169 (2005)
  3. Tsuboi, M. and Suzuki, K., Heterogeneity of initial 87Sr/86Sr ratios within a single pluton: evidence from apatite strontium isotopic study, Chemical Geology, 199, 189-197 (2003)
  4. Magmatic zoisite and epidote in tonalite of the Ryoke belt, central Japan. Yosuke Masumoto, Masaki Enami, Motohiro Tsuboi and Mei Hong, European Journal of Mineralogy, 26, 279-291 (2014).
  5. The role of heterogenetic mantle in the genesis of adakites northeast of Sanandaj, northwestern Iran. Hossein Azizi, Yoshihiro Asahara, Motohiro Tsuboi, Kento Takemura and Saman Razyani, Chemie der Erde, 74, 87-97 (2014).

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