Elucidation of the dynamic magma system by precise time-scale evaluation

2013 Fiscal Year Final Research Report

• Project/Area Number: 23340160
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Petrology/Mineralogy/Science of ore deposit
• Research Institution: Okayama University
• Principal Investigator: NAKAMURA Eizo 岡山大学, 地球物質科学研究センター, 教授 (80201672)
• Co-Investigator(Kenkyū-buntansha): MAKISHIMA Akio 岡山大学, 地球物質科学研究センター, 教授 (70219301) ; TANAKA Ryouji 岡山大学, 地球物質科学研究センター, 准教授 (00379819) ; KOBAYASHI Katsura 岡山大学, 地球物質科学研究センター, 准教授 (20325129)
• Project Period (FY): 2011-04-01 – 2014-03-31
• Keywords: マグマダイナミクス / U-Th-Ra / 放射非平衡 / 表面電離型質量分析計 / マルチコレクションICP-MS / 富士火山 / 斑晶鉱物 / K-Ar年代測定

Research Abstract

In order to understand the dynamic magma system of volcanoes, we attempted to develop new age dating methods then applied them to natural volcanic ejecta. Consequently, we established new U-Th-Ra disequilibrium dating method by using multi collection ICP-MS, and determined the duration of magma supply sequences of Fuji volcano. Additionally, we examined new K-Ar dating combining the spiked and the unspiked sensitivity method to determine eruption ages less than 0.1 Myrs. This method could be successfully applied for lavas from Bratan volcano in Indonesia. The dynamic eruption model regarding supervolcan eruptions driven by melt buoyancy was established.

Research Products

• [Journal Article] Supervolcano eruptions driven by melt buoyancy in large silicic magma chambers (2014)
  • Author(s): Malfait, J. W., Seifert, R., Petitgirard, S., Perrillat, J., Mezouar, M., Ota, T., Nakamura, E., Philippe, L., Sanchez-Valle, C.
  • Journal Title: Nature Geoscience
  • DOI: 10.1038/NGEO2042
• [Journal Article] Sediment-enriched adakitic magmas from the Daisen volcanic field , Southwest Japan (2013)
  • Author(s): Feineman, M., Moriguti, T., Terui, S., Nakamura, E., Yokoyama, T.
  • Journal Title: Geochem . Geophys . Geosyst . Volume: 14 Pages: 3009-3031
  • DOI: 10.1002/ggge.20176
• [Journal Article] K-Ar analyses of the post-caldera lavas of Bratan volcano in Bali Island , Indonesia-Ar isotope mass fractionation to light isotope enrichment (2013)
  • Author(s): Ryu, S., Kitagawa, H., Nakamura, E., Itaya, T., Watanabe, K.
  • Journal Title: J. Volcanol. Geotherm. Res. Volume: 264 Pages: 107-116
  • DOI: 10.1016/j.jvolgeores.2013.07.002
• [Remarks]
  • URL: http://www.misasa.okayama-u.ac.jp