Dehydration and melting process in deep subduction zone-Zircon geochemistry from the Sanbagawa eclogite-

2011 Fiscal Year Final Research Report

• Project/Area Number: 21540468
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geology
• Research Institution: Saitama University
• Principal Investigator: OKAMOTO Kazuaki 埼玉大学, 教育学部, 准教授 (60456001)
• Co-Investigator(Kenkyū-buntansha): TERABAYASHI Masaru 香川大学, 工学部, 教授 (40243745)
• Project Period (FY): 2009 – 2011
• Keywords: 地質学 / 地殻・マントル物質 / 沈み込み帯深部 / 部分融解 / ジルコン / 低温高圧型変成岩 / エクロジャイト / サブダクションファクトリー

Research Abstract

Partial melting texture was discovered from the Sanbagawa eclogoite which had been subducted down to upper mantle at Cretaceous time. Zircons were separated from the eclogite. The zircons exhibit sector zoning on the core to mantle under the CL images. SHRIMP U-Pb age dating and REE analysis from the zircons indicate that the partial melting had occurred in the case of young (hot) slab at upper mantle depth. The melting reaction was due to phengite decomposition. The zircon and the garnet were grown together in the presence of melt.

Research Products

• [Journal Article] Intra-oceanic island arc origin for Iratsu eclogites of the Sanbagawa belt, central Shikoku, southwest Japan (2011)
  • Author(s): Utunomiya, A., Jhan, B., Okamoto, K., Ota, T., Shinjo, H.
  • Journal Title: Chemical Geology Volume: 280 Pages: 97-114
  • Peer Reviewed
• [Journal Article] Thematic section : Fluid-rock interaction in the bottom of the inland seismogenic zone (2010)
  • Author(s): Terabayashi, M., Okamoto, K., Yamamoto, H., Chan Y. C.
  • Journal Title: sland Arc Volume: 19 Pages: 1-3
  • Peer Reviewed
• [Journal Article] 四国中央部三波川変成帯のテクトニクス (2009)
  • Author(s): 岡本和明, 青木一勝, 丸山茂徳
  • Journal Title: 地質学雑誌 Volume: 115巻 Pages: 37-49
  • Peer Reviewed
• [Journal Article] Early Paleozoic medium-pressure metamorphism in central Vietnam : evidence from SHRIMP U-Pb zircon ages (2009)
  • Author(s): Terabayashi, M., Okamoto, K., Usuki, T., Lan, C. Y., Yui, T. F., Iizuka, Y., Vu, V. T., Tran, T. A. Okamoto, K., Wooden, J. L., Liou, J. G.
  • Journal Title: Geosciences Journal Volume: 13 Pages: 245-256
  • Peer Reviewed
• [Journal Article] Detrital zircon evidence for the antiquity of Taiwan (2009)
  • Author(s): Lan, C. Y., T. Usuki, K. L. Wang, T. F. Yui, K. Okamoto, Y. H. Lee, T. Hirata, Y. Kon, Y. Orihashi, J. G. Liou, C. S. Lee
  • Journal Title: Geosciences Journal Volume: 13 Pages: 233-243
  • Peer Reviewed
• [Journal Article] Late Triassic-Late Cretaceous accretion/subduction in the Taiwan region along the eastern margin of South China (2009)
  • Author(s): Yui, T. F., Okamoto, K., Usuki, T., Lan, C. Y., Chu, H. T., Liou, J. G.
  • Journal Title: evidence from zircon SHRIMP dating, International Geology Review Volume: 51 Pages: 304-328
  • Peer Reviewed
• [Presentation] Zircons from the Quartz bearing Sanbagawa Eclogite (2011)
  • Author(s): Arakawa、M., Okamoto, K.
  • Organizer: Asia Oceania Geosciences Society
  • Place of Presentation: Taipei
  • Year and Date: 2011-08-11
• [Presentation] ジルコンから読み取る沈み込み帯深部の部分融解過程-三波川エクロジャイトを用いて- (2011)
  • Author(s): 荒川幸, 岡本和明, 堤之恭, 寺林優
  • Organizer: 地球惑星連合大会
  • Place of Presentation: 幕張
  • Year and Date: 2011-05-26
• [Presentation] Arakawa Miyuki Partial melting of deeply sub ducted metasediment-discovery of the melting textures from the quartz bearing eclogite in the Sanbagawa belt- (2011)
  • Author(s): Okamoto, K.
  • Organizer: 地球惑星連合大会
  • Place of Presentation: 幕張
  • Year and Date: 2011-05-23
• [Presentation] Partial melting of deeply sub ducted metasediment-discovery of the melting textures from the quartz bearing eclogite in the Sanbagawa belt (2010)
  • Author(s): Okamoto, K., Utsunomiya, A.
  • Organizer: Japan Western Pacific Geophysical Union
  • Place of Presentation: Taipei
  • Year and Date: 2010-06-22
• [Presentation] Importance of ferric estimation based on Mossbauer and micro-XANES analysis- (2009)
  • Author(s): Okamoto, K., Jahn, B., Yui, T.F., Akasaka, M., Xu, Z.
  • Organizer: 8th International Eclogite Conference
  • Place of Presentation: Xining, Qinghai, China
  • Year and Date: 2009-08-28