Genesis and secular changes of Pacific LIPs: Approch from plume-type ophiolites in Japan

• Project/Area Number: 16K17831
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Chiba University
• Principal Investigator: Ichiyama Yuji 千葉大学, 大学院理学研究院, 助教 (90625469)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: オフィオライト / 付加体 / ウラン鉛年代 / マントルプルーム / 海洋性島弧 / 嶺岡・瀬戸川帯 / みかぶ帯 / 虫川コンプレックス / 伊豆・ボニン・マリアナ弧 / ジルコンU-Pb年代

Outline of Final Research Achievements

The investigations of igneous rocks in Japanese accretionary complexes and ophiolites provided the following results. (1) Igneous rocks in the Mineoka-Setogawa belt are fragments of the Izu-Bonin arc, and the model for the formation mechanisms of deep-seated crustal rocks beneath the Izu-Bonin arc was established. (2) Detailed radiogenic ages for the protoliths in the Mikabu and Sorachi-Yezo belts were determined, and the clue to understanding Pacific mantle plume in Late Jurassic was found out. (3) Two different radiometric ages were obtained from the Permian Mushikawa complex, and tectonics in Paleozoic east Asian continental margins was revealed.

Academic Significance and Societal Importance of the Research Achievements

日本列島に分布する付加体やオフィオライトは、過去の太平洋で形成された海洋性地殻～上部マントルの断片である。様々な年代の付加体やオフィオライトを構成する岩石の化学組成や年代を研究することによって、顕生代以降6億年の間、太平洋で起きた火成活動の変遷を理解することができる。また、地表では見られない深部火成プロセスを観察することも可能である。本研究では、ジュラ紀末に巨大なマントルプルームが活動していたこと、古生代後期の大陸縁辺部での地質学的環境が明らかとなった。そして伊豆・ボニン弧のような海洋性島弧の中部～下部地殻の形成過程が解明された。

Research Products

• [Journal Article] Early Miocene island arc tholeiite in the Mineoka Belt: Implications for genetic relationship with the Izu–Bonin–Mariana (IBM) arc (2018)
  • Author(s): Enomoto, H., Ichiyama, Y., and Ito, H.
  • Journal Title: Journal of Mineralogical and Petrological Sciences Volume: 113 Issue: 4 Pages: 190-197
  • DOI: 10.2465/jmps.180118
  • NAID: 130007474679
  • ISSN: 1345-6296, 1349-3825
  • Peer Reviewed / Open Access
• [Journal Article] Plutonic rocks in the Mineoka-Setogawa ophiolitic melange, central Japan: Fragments of middle to lower crust of the Izu-Bonin-Mariana Arc? (2017)
  • Author(s): Yuji Ichiyama, Hisatoshi Ito, Natsumi Hokanishi, Akihiro Tamura, Shoji Ara
  • Journal Title: Lithos Volume: 282-283 Pages: 420-430
  • DOI: 10.1016/j.lithos.2017.03.021
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] マリアナ蛇紋岩海山の変成苦鉄質岩・超苦鉄質岩の多様性：海溝軸からの距離依存 (2019)
  • Author(s): 市山祐司
  • Organizer: 変成岩などシンポジウム
• [Presentation] Zircon U-Pb ages of the Mikabu ophiolitic belt, Southwest Japan: Implications for the origin of the Shatsky Rise (2018)
  • Author(s): Ichiyama, Y., Takahashi, S., and Ito, H.
  • Organizer: European Geosciences Union
  • Int'l Joint Research
• [Presentation] High-pressure metamorphism and mantle metasomatism in the Mariana convergent margin: Petrology of mafic and ultramafic clasts recovered from IODP Exp. 366 (2018)
  • Author(s): Ichiyama, Y., Michibayashi, K., and Fryer, P.
  • Organizer: Japan Geoscience Union
  • Int'l Joint Research
• [Presentation] Various metamorphism and serpentinization of mafic and ultramafic clasts from the Mariana serpentinite seamounts (2018)
  • Author(s): Ichiyama, Y., Michibayashi, K., and Fryer, P.
  • Organizer: American Geophysical Union
  • Int'l Joint Research
• [Presentation] 新潟県青海地域虫川コンプレックスに産する2つの異なるジルコンU-Pb年代を示す古生代苦鉄質岩ブロック (2018)
  • Author(s): 小芝隆仁・市山祐司・伊藤久敏・田村明弘
  • Organizer: 日本地質学会
• [Presentation] 嶺岡・瀬戸川帯火山岩類の岩石化学とジルコンU-Pb年代 (2017)
  • Author(s): 榎本葉月，市山祐司，伊藤久敏，田村明弘，荒井章司
  • Organizer: JpGU
• [Presentation] IODP第366航海概報：マリアナ前弧蛇紋岩海山から得られた岩石 (2017)
  • Author(s): 市山祐司
  • Organizer: InterRidge-Japan研究集会
• [Presentation] Arc magma-induced mantle refertalization: a case study of plagioclase peridotite in the Mineoka-Setogawa Belt, central Japan (2017)
  • Author(s): Ichiyama, Y.
  • Organizer: JpGU
• [Presentation] Reconstruction of the Mineoka-Setogawa ophiolitic mlange: deciphering evolution of the Izu-Bonin-Mariana Arc (2017)
  • Author(s): Ichiyama, Y., Enomoto, H., Ito, H., Tamura, A. and Arai, S.
  • Organizer: Goldshmidt Conference
• [Presentation] 嶺岡・瀬戸川帯苦鉄質～珪長質深成岩類の岩石学： 伊豆・ボニン・マリアナ弧中部地殻の成因 (2016)
  • Author(s): 市山祐司・伊藤久敏・外西奈津美・田村明弘・荒井章司
  • Organizer: 日本鉱物科学会
  • Place of Presentation: 金沢大学（石川県・金沢市）
  • Year and Date: 2016-09-23
• [Presentation] 嶺岡・瀬戸川帯かんらん岩類の再検討： IBM 前弧玄武岩の溶け残りマントルか？ (2016)
  • Author(s): 市山祐司
  • Organizer: 日本地質学会
  • Place of Presentation: 日本大学（東京都・世田谷区）
  • Year and Date: 2016-09-10
• [Presentation] Petrogenesis of plutonic rocks in the Mineoka-Setogawa Belts: Toward understanding of deep crustal rocks in the IBM Arc (2016)
  • Author(s): Ichiyama, Y., Ito, H., Hokanishi, N., Tamura, A., Arai, S.
  • Organizer: Gold Schmidt Conference
  • Place of Presentation: パシフィコ横浜（神奈川県・横浜市）
  • Year and Date: 2016-06-26
  • Int'l Joint Research
• [Presentation] Zircon U-Pb age and geochemistry of plutonic rocks in the Mineoka-Setogawa Belts: Fragments of middle to lower crust of the IBM Arc? (2016)
  • Author(s): Ichiyama, Y., Ito, H., Hokanishi, N., Tamura, A., Arai, S.
  • Organizer: JpGU
  • Place of Presentation: 幕張メッセ（千葉県・千葉市）
  • Year and Date: 2016-05-22