Kyushu University Academic Staff Educational and Research Activities Database
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Akira Imai Last modified date:2022.06.27

Graduate School
Undergraduate School
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 Reseacher Profiling Tool Kyushu University Pure
Academic Degree
Field of Specialization
Economic Geology, Resource Geology
Outline Activities
Specialty in economic geology, resource geology, with special interest in magmatic hydrothermal system where porphyry copper and epithermal gold deposits are formed associated with magmatism in plate boundaries.
Methods in research in economnic geology, ore deposit geology are tought, and graduates are expected to be exploration geologists in global activity.
A member of advisory committee of Metal Mining Agency of Japan, and a member of Japanese supporting university in Asian University Network (AUN/SEED-Net) suponsored by Japanese government.
Research Interests
  • Magmatic hydrothermal system associated with magmatism at plate boundaries with focus on metallogenesis of porphyry copper and eppithermal gold deposits
    keyword : magmatic hydrothermal system, porphyry copper deposits, epithermal gold deposits, metallogenesis
    1987.04~2020.03Magmatic hydrothermal system associated with magmatism at plate boundaries: porphyry copper and epithermal gold deposits and their metallogeneses.
Current and Past Project
  • This project aims to reveal metallonenesis such as geological process and condition to form porphyry copper and eipthermal deposits in ancient arc settings, which are presently located in continental region, such as Central Asia and Indo-China region, though geological reconstruction.
  • Application of fluid inclusion microthermometry to exploration of porphyry Cu prospect in oreanic island arc.
  • Metallogeneses of porphyry Cu and epithermal Au deposits in oreanic island arcs.
  • Establishment of archeologic ancient Japanese nation by determination of the origin of cinnabar buried in tombs
Academic Activities
1. A. Imai, C. B. Dimalanta, A. Idrus, I W. Warmada and A. Harijoko, Resource Geology Thematic Issue: Collection of Achievements on Earth Resources from AUN/SEED-Net III., Wiley, 2009.10.
2. A. Imai, C. B. Dimalanta, A. Harijoko, Resource Geology Special Issue: Achievements on Earth Resource from AUN/SEED-Net Part II, Society of Resource Geology, 2007.06.
3. A. Imai, C. B. Dimalanta, G. P. Yumul, Jr., l. D. Setijadji, K. Watanabe, Resource Geology Special Issue: : Achievements on Earth Resource from AUN/SEED-Net, Society of Resource Geology, 2005.09.
4. E. IZAWA, K. WATANABE, A. IMAI, Resource Geology Special Issue: Papers Presented at the International Symposium on Gold and Hydrothermal Systems, Society of Resource Geology, 2002.12.
5. G. P. YUMUL, Jr., A. IMAI, Resource Geology Special Issue: Mineralization and Hydrothermal Systems in the Philippines, Society of Resource Geology, 2001.06.
1. Cirineo, A. V. L., Imai, A., Takahashi, R., Baluda, R. P., Oliveros, N., Maglambayan, V. B., Luis, R. R., Faustino, M. L. M. and Almadin, J., Overprinting porphyry-type veinlets on the intrusive rocks and phreatomagmatic breccias in the Southwest prospect, southwestern Sto. Tomas II (Philex), Baguio District, Philippines, Resource Geology, DOI: 10.1111/rge12242, 71, 1, 1-40, 71 (1), 1-40. , 2021.01.
2. Imai, Akira, Ohbuchi Yukiko, Tanaka Takayuki, Morit Seita, Yasunaga Kentaro, Characteristics of porphyry Cu mineralization at Waisoi (Namosi district), Viti Levu, Fiji, Resource Goelogy, 57巻4号374-385頁, 2007.12.
3. Yonezu Kotaro, Yokoyama Takushi, Okaue Oyoshihiro, Imai Akira, Watanabe Koichiro, Concentration of gold(I) thiosullfate complex ions on the surface of alumina gel and their change in chemical state: Preliminary experiment in the elucidation of the formation mechanism of epithermal gold deposits, Resource Geology, 2007.12.
4. Kotaro Yonezu, Takushi Yokoyama, Yoshihiro Okaue, Akira Imai, Koichiro Watanabe, Concentration of gold(I) Thiosulfate complex ions on the surface of alumina gel and their change in chemical state Preliminary experiment in the elucidation of the formation mechanism of epithermal gold deposits, Resource Geology, 10.1111/j.1751-3928.2007.00035.x, 57, 4, 400-408, 2007.12, In order to elucidate the formation mechanism of low-sulfidation epithermal gold deposit, the adsorption of [Au(S2 O3)2]3- (a model compound for gold(I) complex ion) on alumina gel (a model compound for the aluminum-bearing minerals) and change in chemical state of [Au(S2 O3)2]3- after adsorption on the surface of alumina gel were investigated as a basic model experiment. In the pH range from 4 to 6, the amount of [Au(S2 O3)2]3- adsorbed on alumina gel decreased with increasing pH and decreased drastically between pH 6 and 7, and then approached zero above pH 8 at 30°C. At 60°C, the amount of gold adsorbed above pH 7 was enhanced compared with that at 30°C. This adsorption tendency indicates that [Au(S2O3)2]3- is mainly adsorbed by electrostatic interaction between negative charges of [Au(S2O3)2]3- and positive charges of alumina gel because of its isoelectric point around pH 9. The chemical state of gold after adsorption of [Au(S2 O3)2]3- on alumina gel was examined using X-ray absorption near edge structure (XANES). The result showed that [Au(S2O3)2]3- was spontaneously reduced to elemental gold even in the absence of specific reducing agents after adsorption on alumina gel. This reduction reaction might occur by two steps: (i) disproportionation of the adsorbed [Au(S2O3)2]3- at the surface of alumina gel, and (ii) spontaneous reduction of the resulting gold(III) complex ions on the surface of alumina gel. The experimental results suggest that aluminum plays an important role in the concentration of gold(I) complex ions and subsequent reduction of gold during the formation of low-sulfidation epithermal gold deposits..
5. Harijoko, A., Ohbuchi, Y., Motomura, Y., Imai, A. and Watanabe, K., Characteristics of the Cibaliung gold deposit: A Miocene low sulfidation type epithermal gold deposit at the western Java, Indonesia, Resource Geology, 57巻2号, 2007.06.
6. Syafrizal, Imai, A. and Watanabe, K., Origin of ore-forming fluids responsible for gold mineralization of the Pongkor Au-Ag deposit, West Java, Indonesia: Evidences from mineralogic, fluid inclusion microthermometry and stable isotope study of the Ciurug-Cikoret vein, Resource Geology, 57巻2号, 2007.06.
7. Suerte, L. O., Nishihara, S., Imai, A., Watabnabe, K., Yumul, G. P., Jr. and Maglambayan, V. B., The occurrences of ore minerals and fluid inclusion study on the Kingking porphyry copper-gold deposit, eastern Mindanao, Philippines, Resource Geology, 57巻2号, 2007.06.
8. Imai, A., Shinomiya, J., Soe, M. T., Setijadji, L. D., Watanabe, K. and Warmada, I W., Porphyry-type mineralization at Selogiri area, Wonogiri regency, central Java, Indonesia, Resource Geology, 57巻2号, 2007.06.
9. Imai, A. Geshi, N., Shimano, T. and Nakada, S., Implication of sulfur isotopic variation to 2000 eruptions of Miyake-jima volcano, Izu arc, Island Arc, 16, 83-92., 2007.03.
10. Setijadji, L. D., Kajino, S., Imai, A. and Watanabe, K., Cenozoic island arc magmatism in Java Island (Sunda Arc, Indonesia): Clues on relationships between geodynamics of volcanic centers and ore mineralization, Resource Geol., 56, 267-292., 2006.01.
11. Ishihara, S., Ohmoto, H., Anhaeusser, C. L., Imai, A., and. Robb, L. J., Discovery of the oldest oxic granitoids in the Kaapvaal Craton and its impolication for the redox evolution of early Earth, Geol. Soc. Amer. Memoir, 198, 67-80., 2006.01.
12. Minami, T., Imai, A., Bunno, M., Kawakami, K. and Imazu, S., Using sulfur isotope to determine the sources of vermillion in ancient burial mounds in Japan, Geoarcheology, 20, 79-84., 2005.01.
13. Imai, A., Evolution of hydrothermal system at the Dizon porphyry Cu-Au deposit, Zambales, Philippines, Resource Geol., 55, 73-90., 2005.01.
14. Syafrizal, Imai, A., Watanabe, K. and Motomura, Y., Mineralization at the Ciurug vein, Pongkor gold-silver deposit, Indonesia, Resource Geol., 55, 225-238., 2005.01.
15. Imai, A. and Ohno, S., Primary ore mineral assemblage and fluid inclusion study of the Batu Hijau porphyry Cu-Au deposit, Sumbawa, Indonesia, Resource Geol., 55, 239-248., 2005.01.
16. Sanematsu, K., Duncan, R., Imai, A. and Watanabe, K., Geochronological constraints using 40Ar/39Ar dating on the mineralization of the Hishikari epithermal gold deposit, Japan, Resource Geol., 55, 249-266., 2005.01.
17. Aramaki, Y., Yokoyama, T., Okaue, Y., Imai, A. and Watanabe, K., A study on the formation of smectite in silica scale formed from geothermal water: The effect of magnesium, Resource Geol., 55, 281-284., 2005.01.
18. Imai, A., Occurrence of halogen-rich phlogopite in Late Cenozoic volcanic rocks in the Japanese arcs, Resource Geol, 55, 225-238., 2004.01.
19. Imai, A., Variation of Cl and SO3 contents of microphenocrystic apatite in intermediate to silicic igneous rocks of Cenozoic Japanese Island Arcs: Implications for porphyry Cu metallogenesis in the Western Pacific Island Arcs, Resource Geol.,, 54, 357-372., 2004.01.
20. Imai, A., Metallogenesis of porphyry Cu-Au deposits of the western Luzon arc, Philippines: K-Ar ages, SO3 contents of microphenocrystic apatite and significance of intrusive rocks., Resource Geology, 52, 147-161, 2002.06.
21. Imai, A., Mineral paragenesis, fluid inclusions and sulfur isotope systematics of the Lepanto Far Southeast porphyry Cu-Au deposit, Mankayan, Benguet, Philippines., Resource Geology, 50, 151-168, 2000.09.
22. Imai, A., Genesis of the Mamut porphyry Cu deposit, Sabah, East Malaysia., Resource Geology, 50, 1-23, 2000.03.
23. Spinifex texture of native sulfur: A cooling product of sulfur flow eruptions at Shiretoko-Iwozan volcano, Hokkaido, Japan.
24. Imai, A., Matsueda, H., Yamada, R. and Masuta, K., Polymetallic mineralization at the Shin-Ohtoyo deposit, Harukayama district, Hokkaido, Japan., Resource Geology, 49, 75-88, 1999.06.
25. Iizasa, K., Fiske, R. S., Ishizuka, O., Yuasa, M., Hashimoto, J., Ishibashi, J., Naka, J., Horii, Y., Fujiwara, Y., Imai, A. and Koyama, S., A Kuroko-type polymetallic sulfide deposit in a submarine silicic caldera., Science, 283, 975-977, 1999.02.
26. Maglambayan, V. B., Ishiyama,D., Mizuta, T., Imai, A. and Ishikawa, Y., Geology, alteration, and formation environment of the disseminated gold-silver telluride Bulawan deposit, Negros Occidental, Philippines., Resource Geology, 48, 87-104, 1998.06.
27. Ishizuka, O. and Imai, A., "Brown Ore" from the Fukasawa kuroko deposits, northeast Japan: Its characteristics and formation process., Resource Geology, 48, 53-73, 1998.06.
28. Imai, A., Listanco, E. L. and Fujii, T., Highly oxidized and sulfur-rich magma of Mount Pinatubo: Implication for metallogenesis of porphyry copper mineralization in the western Luzon arc., Newhall, C. G. and Punongbayan, R. S., eds., Fire and Mud: Eruptions and Lahars of Mount Pinatubo, Philippines, 865-874, 1996.12.
29. Imai, A. and Ozawa, K., Tectonic implication of the hydrated garnet peridotites near Mt. Kinabalu, Sabah, East Malaysia, Jour. Southeast Asian Earth Sci., 6, 431-445., 1991.12.
Membership in Academic Society
  • Society of Resource Geology
  • Society of Geology Applied to Mineral Deposits
  • International Association of Genesis of Ore Deposits
  • Geological Society of the Philippines
  • Geological Society of the Philippines
  • Society of Economic Geologists
Educational Activities
Exercize in Geological Survey
Economic Geology I
Exercize in Environmental Engineering
Internship in Resource Engineering
Introduction to Earth System
International Special Cource on Environmental Engineering
Other Educational Activities
  • 2022.04.
  • 2021.04.
  • 2003.09.
  • 2004.01.
Professional and Outreach Activities
Lecturer on Special Training Course of the Society of Resource Geology (1991, 1995).