Kyushu University Academic Staff Educational and Research Activities Database
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Junji Yamamoto Last modified date:2023.01.13

Professor / Material Science of Solar Planets
Department of Earth and Planetary Sciences
Faculty of Sciences


Graduate School
Undergraduate School


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Homepage
https://kyushu-u.pure.elsevier.com/en/persons/junji-yamamoto
 Reseacher Profiling Tool Kyushu University Pure
Phone
092-802-4215
Fax
092-802-4208
Academic Degree
Ph. D.
Country of degree conferring institution (Overseas)
No
Field of Specialization
Chemistry in the Earth system
ORCID(Open Researcher and Contributor ID)
0000-0002-2636-1002
Total Priod of education and research career in the foreign country
03years01months
Outline Activities
I am exploring chemically how the Earth was born, how it developed into its present state, and what it will be in the future. On the social learning, I am conducting activities to clarify ambiguous spatio-temporal scale of "environment".
Research
Research Interests
  • Four-dimensional exploration of the lithospheric mantle
    Identifying the source asteroid of the Earth
    Probability of layered mantle convection
    Development of Raman spectroscopic isotope analysis method
    keyword : Mantle, isotope, physical properties of minerals, fluid inclusion, spectroscopy
    2021.10~2021.10.
Academic Activities
Papers
1. Yamamoto J. and Kurz M.D., Noble gas isotopic compositions and abundance ratios of mantle xenoliths from Honolulu series volcanism, Oahu, Hawaii, Earth and Planetary Science Letters, https://doi.org/10.1016/j.epsl.2022.117979, 603, 117979, 2023.01, We report new noble gas isotopic compositions and abundance ratios (helium, neon, and argon) extracted from six lherzolite xenoliths on Oahu Island, Hawaii, by vacuum crushing. Considering the equilibrium temperature of the xenoliths and the fluid density of their fluid inclusions, they originated from a pressure of 0.98–1.04 GPa, corresponding to 33–34 km depth. The Moho depth beneath Oahu Island is around 15 km, suggesting that the xenoliths are part of the sub-oceanic lithospheric mantle (SOLM), 90 million years old, after generation of mid-oceanic ridge basalts (MORB). The samples have 3He/4He of 3.0–9.5 times atmosphere (Ra). The neon isotope compositions overlap with the data of previous studies for lava flow samples of the Hawaiian Islands, MORB, and air. The 40Ar/36Ar range from atmospheric to 3100. They show very low 4 He/40 Ar* and 4 He/21 Ne*, where asterisks denote correction for atmospheric contributions. The low 4He/40Ar* and 4He/21Ne* are characteristic of small fluid inclusions, based on step crushing experiments, indicating that they record kinetic fractionation that occurred in the SOLM most likely due to melt infiltration. Using 4 He/40 Ar* and 20 Ne/22 Ne respectively as indices of the kinetic fractionation and atmospheric contribution, we corrected for these effects. The corrected noble gas isotopic compositions are best explained by interaction between plume-derived melts and SOLM. The kinetic fractionation yields a decrease in 3He/238U in SOLM, which should result in a rapid decrease in 3He/4He with time. The slightly elevated 3He/4He (above 8 times atmospheric), as found in the present xenoliths cannot be maintained for more than one million years in the fractionated SOLM with 3He/U molar ratio of ∼1 × 10−8, which is calculated assuming that the 3He/U has the same degree of kinetic fractionation as 4He/40Ar* and 4He/21Ne*. Therefore, the fractionation event is likely to be recent, and may be related to recent magmatism in the SOLM beneath Oahu Island. Such igneous activity is limited to Honolulu series volcanism (0.35–0.80 Ma). Therefore, the xenoliths contain a record of magmas with plume-derived noble gases, most likely associated with the Honolulu series volcanism..
2. Junji Yamamoto, Jun Korenaga, Naoto Hirano, Hiroyuki Kagi, Melt-rich lithosphere-asthenosphere boundary inferred from petit-spot volcanoes, GEOLOGY, 10.1130/G35944.1, 42, 11, 967-970, 2014.11.
Works, Software and Database
1. .
2. .
Membership in Academic Society
  • TOKYO GEOGRAPHICAL SOCIETY
  • Japan Association of Mineralogical Sciences
  • THE JAPANESE SOCIETY FOR ENVIRONMENTAL EDUCATION
  • JAPAN GEOSCIENCE UNION
  • THE GEOCHEMICAL SOCIETY OF JAPAN
  • JAPAN SOCIETY OF EARTH SCIENCE EDUCATION
  • The Geochemical Society
  • American Geophisical Union
Awards
  • Incentive Award of The Geochemical Society of Japan
Educational
Educational Activities
In order to increase the educational effect, it would be effective to stimulate the learning motivation of students. I am therefore investigating the class evaluation to identify the factors that can stimulate and improve students' learning motivation, and to explore the educational system that can continue the learning motivation even after the class period.
Other Educational Activities
  • 2021.11, Yamamoto J. and Tokunaga S. (2021) Factors affecting overall evaluation of a class: Exploring factors improving learning motivation. Journal of Higher Education and Lifelong Learning, in press..
  • 2021.10, Yamamoto J. and Tokunaga S. (2021) Analogical Extended Expression for Understanding of Earth's Spatio-Temporal Scale. Environmental Education, in press..
  • 2019.12, Yamamoto J.,Tokunaga S., Asahi H., Odajima M. and Abe T.(2020)Improvement of a Teaching Material for the Earth’s Layered Structure. Education of Earth Science 72,115-128..
  • 2019.05, Yamamoto J., Tokunaga S., Tanaka T., Tajima T. (2019) Development of a Teaching Material for the Earth’s Layered Structure: A Sensory Tool for Specific Gravity. Education of Earth Science 72, 31-42..
  • 2017.05, Yamamoto J., Tokunaga S., Tanaka T., Takahata K., Tajima T., Mishima W. (2017) Development of educational tool for formation processes of graded layers -a sensory tool for viscous resistance of a media-. Education of Earth Science70, 31-41..
  • 2017.03, Mishima W., Yamamoto J., Arita K., Kato Y., Tanaka T., Torimoto J., Takahata K., Kusaka A. and Teranishi T. (2017) Potential of Mortar as an Experimental Material for Aid in Understanding of Rock Weathering by Freezing and Thawing. Education of Earth Science 70, 15-22..
  • 2015.07, Mishima W., Yamamoto J., Arita K., Torimoto J., Tanaka T. and Sakai M. (2015) Development of an experimental method in education to aid understanding of rock weathering brought about by freezing and thawing. Education of Earth Science 68, 59-67..
  • 2014.06, Shitaoka Y., Honjo M., Watanabe K., Kawahara M., Yamamoto J., Mithosh M., Nakano H., Hiraga S. and Takemura K. (2014) Comparative Analysis of availability of Magma formation program using Portable Clay Cooking Stove. Environmental Education, 24, 85-91..
  • 2013.03, Tokunaga S., Yamamoto J. (2013) Responsiveness of environmental education to the Great East Japan Earthquake ―Science Cafe―. Environmental Education after the Great East Japan Earthquake (Environmental Education in Japan), pp. 209, The Japanese Society of Environmental Education, Tokyo..
  • 2012.03, Shitaoka Y., Miyoshi M., Yamamoto J., Miyoshi M. and Takemura K.(2012)Study program to estimate hinterland using several separation methods for beach samd. Education of Earth Science 65, 51-61..
  • 2012.03, Yamamoto J., Tokunaga S. and Shitaoka Y.(2012)Availability of mantle carbon as an educational resource for environmental education. Environmental Education 21, 64-73..
  • 2011.05, Shitaoka Y., Miyoshi M., Mawatari H., Yoshikawa S., Yamamoto J., Watanabe K., Saito T., Sugimoto T., Yamada M., Miyoshi M. and Takemura K.(2011)Observation of magma formation using familiar products (in Japanese with English abstract). Education of Earth Science 64, 53-69..