Details of the Researcher

PHOTO

Naoto Hirano
Section
Center for Northeast Asian Studies
Job title
Professor
Degree

  • 博士（理学）（筑波大学）

  • 修士（理学）（筑波大学）

Research History 9

  • 2013/04 - 2025/03
    Tohoku University　Center for Northeast Asian Studies

  • 2008/12 - 2013/03
    Tohoku University　Center for Northeast Asian Studies

  • 2008/07 - 2008/11
    Frontier Science Organization, Kanazawa University　研究員

  • 2007/04 - 2008/06
    Earthquake Chemistry, University of Tokyo　研究員

  • 2006/05 - 2007/03
    Scripps Institution of Oceanography, University of California, San Diego　研究員

  • 2004/04 - 2006/04
    Faculty of Science, Tokyo Institute of Technology　研究員

  • 2002/04 - 2004/03
    Earthquake Research Institute, University of Tokyo　研究員

  • 2002/04 - 2004/03
    Faculty of Science, Tokyo Institute of Technology　研究員

  • 2001/04 - 2002/03
    Ocean Reasearch Institute, University of Tokyo　研究員

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Education 2

  • University of Tsukuba　Graduate School, Division of Earth Science　地質学専攻

    - 2001/03

  • Yamagata University　Faculty of Science　地球科学科

    - 1996/03

Committee Memberships 8

  • 海底地形の名称に関する検討会　外部委員

    2024/04 - Present

  • 東京大学大気海洋研究所共同利用共同研究運営委員会 陸上共同研究部会　外部委員

    2023/04 - Present

  • 日本地質学会　代議員（地方支部区）

    2014/01 - 2022/03

  • 日本地球化学会　広報委員

    2014/01 - 2019/09

  • J-DESC IODP部会執行部　執行委員

    2013/04 - 2015/05

  • 日本地球化学会　広報委員

    2012/01 - 2013/12

  • 日本地球化学会　評議員

    2010/01 - 2011/12

  • J-DESC IODP部会執行部　執行委員

    2009/04 - 2011/03

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Professional Memberships 5

  • JpGU

  • American Geophysical Union

  • 日本地球化学会

  • 日本鉱物科学会

  • 日本地質学会

Research Areas 2

  • Natural sciences / Space and planetary science /

  • Natural sciences / Solid earth science /

Awards 2

  1. 日本地球化学会奨励賞

    2008/09　日本地球化学会　沈み込む海洋プレート上の新タイプ火山活動の発見とメカニズムの解明

  2. 日本岩石鉱物鉱床学会研究奨励賞

    2007/09　日本岩石鉱物鉱床学会

Papers 85

  1. Contribution of carbonatite and recycled oceanic crust to petit-spot lavas on the western Pacific Plate Peer-reviewed

    Kazuto Mikuni, Naoto Hirano, Shiki MacHida, Hirochika Sumino, Norikatsu Akizawa, Akihiro Tamura, Tomoaki Morishita, Yasuhiro Kato

    Solid Earth　15　(2)　167-196　2024

    DOI： 10.5194/se-15-167-2024 　

    ISSN： 1869-9510

    eISSN： 1869-9529

  2. An intraoceanic juvenile arc of shoshonite and adakitic andesite in the Nemuro Belt, the Lesser Kuril Arc, across the K/Pg boundary Peer-reviewed

    Taku Yutani, Naoto Hirano, Hirotaka Tanaka, Hirochika Sumino, Shiki Machida, Shun Sekimoto, Shigekazu Yoneda, Yasuhiro Kato

    Cretaceous Research　147　105510-105510　2023/07

    Publisher: Elsevier BV

    DOI： 10.1016/j.cretres.2023.105510 　

    ISSN： 0195-6671

  3. Hydrothermal ferromanganese oxides around a petit-spot volcano on old and cold oceanic crust Peer-reviewed

    Keishiro Azami, Shiki Machida, Naoto Hirano, Kentaro Nakamura, Kazutaka Yasukawa, Tetsu Kogiso, Masao Nakanishi, Yasuhiro Kato

    Communications Earth & Environment　4　(1)　2023/06/01

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43247-023-00832-3 　

    eISSN： 2662-4435

    More details Close

    Abstract Areas of old and cold oceanic plate lack conventional volcanism and have been assumed to be devoid of submarine hydrothermal activity. However, petit-spot volcanoes are common in areas of flexure of such oceanic plates. Here, we report hydrothermal ferromanganese oxides dredged from the vicinity of a petit-spot volcano at 5.7 km water depth in an area of oceanic plate flexure east of the Japan Trench. The bulk chemical, lead isotopic and mineralogical compositions of the samples indicate their formation by low-temperature hydrothermal activity, which can be interpreted as being caused by fluid–rock interactions at <200 °C. We propose that interaction of local marine sediments with volatile-rich petit-spot magmas may produce hydrothermal fluids containing not only iron and manganese but also enough amounts of carbon dioxide and methane to have implications for the global carbon cycle. However, contemporary hydrothermal activities at petit-spot volcanoes have not been confirmed yet.

  4. Lithological structure of western Pacific lithosphere reconstructed from mantle xenoliths in a petit-spot volcano Peer-reviewed

    Kazuto Mikuni, Naoto Hirano, Norikatsu Akizawa, Junji Yamamoto, Shiki Machida, Akihiro Tamura, Yuuki Hagiwara, Tomoaki Morishita

    Progress in Earth and Planetary Science　9　(1)　2022/11/12

    DOI： 10.1186/s40645-022-00518-y 　

    ISSN： 2197-4284

    eISSN： 2197-4284

  5. The mantle structure below petit-spot volcanoes Peer-reviewed

    Naoto Hirano, Shiki Machida

    COMMUNICATIONS EARTH & ENVIRONMENT　3　(1)　2022/05

    DOI： 10.1038/s43247-022-00438-1 　

    eISSN： 2662-4435

  6. A Paleogene magmatic overprint on Cretaceous seamounts of the western Pacific

    Naoto Hirano, Hirochika Sumino, Taisei Morishita, Shiki Machida, Takaomi Kawano, Kazutaka Yasukawa, Takafumi Hirata, Yasuhiro Kato, Teruaki Ishii

    Island Arc　30　(1)　2021/01/03

    DOI： 10.1111/iar.12386 　

    ISSN： 1038-4871

    eISSN： 1440-1738

  7. Intact Pacific oceanic crust captured as mafic xenoliths in a petit-spot volcano Peer-reviewed

    Kazuto Mikuni, Naoto Hirano, Shiki Machida, Norikatsu Akizawa, Shigekazu Yoneda, Akihiro Tamura, Tomoyuki Mizukami, Yasuhiro Kato, Tomoaki Morishita

    Marine Geology　483　2025

    DOI： 10.1016/j.margeo.2025.107497 　

    ISSN： 0025-3227

  8. Petrography and stratigraphic Os isotopic ages of ferromanganese nodules from the Northwest Pacific east of Minamitorishima Island Peer-reviewed

    Tatsuo Nozaki, Kosuke T. Goto, Yutaro Takaya, Kazuhiko Shimada, Akira Owada, Gen Shimoda, Jun-Ichi Kimura, Qing Chang, Tetsuji Onoue, Shiki Machida, Teruaki Ishii, Kenji Shimizu, Naoto Hirano, Kazuhide Mimura, Moei Yano, Junichiro Ohta, Yasuhiro Kato

    Journal of Asian Earth Sciences: X　100176-100176　2024

    Publisher: Elsevier BV

    DOI： 10.1016/j.jaesx.2024.100176 　

    ISSN： 2590-0560

  9. 87Sr/86Sr Isotopic Ratio of Ferromanganese Crusts as a Record of Detrital Influx to the Western North Pacific Ocean Peer-reviewed

    Keishiro Azami, Naoto Hirano, Jun-Ichi Kimura, Qing Chang, Hirochika Sumino, Shiki Machida, Kazutaka Yasukawa, Yasuhiro Kato

    Minerals　12　(8)　943-943　2022/07/27

    Publisher: MDPI AG

    DOI： 10.3390/min12080943 　

    eISSN： 2075-163X

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    In this study, the Sr isotope ratios (IRs; 87Sr/86Sr) of ferromanganese (Fe–Mn) crusts are analyzed through laser ablation inductively coupled plasma multiple-collector mass spectrometry. A sample collected from off Minamitorishima Island showed uniform Sr IRs (0.70906–0.70927) similar to that of present-day seawater with more than 36 mm thickness. Meanwhile, a detritus-rich sample collected from off northeast (NE) Japan showed a wide variation in Sr IRs (0.707761–0.709963). The Sr IR variation in the Fe–Mn crust from off NE Japan suggests detrital influx contributions from both the NE Japan arc (<0.708) and aeolian dust from China (>0.718). Detrital flux from the NE Japan arc increases from the bottom to middle layers, possibly due to the uplift of the Ou backbone range that occurred after ~2 Ma. The increased influx of the aeolian dust in the outer layer is attributable to global cooling in the Quaternary that increased the loess dust transportation from China to the western North Pacific Ocean. Meanwhile, the influence of the detrital influx on the sample from off Minamitorishima Island appeared to be negligible. The Sr IR analysis with high spatial resolution proposed in this study possibly improves the burial history of Fe–Mn nodules.

  10. A direct evidence for disturbance of whole sediment layer in the subducting Pacific plate by petit-spot magma–water/sediment interaction Peer-reviewed

    Norikatsu Akizawa, Naoto Hirano, Kenji M. Matsuzaki, Shiki Machida, Chiori Tamura, Junji Kaneko, Hideki Iwano, Tohru Danhara, Takafumi Hirata

    Marine Geology　444　2022/02

    DOI： 10.1016/j.margeo.2021.106712 　

    ISSN： 0025-3227

  11. Near bottom MBES survey mounted on a HOV at 5500m depth

    Junji Kaneko, Shiki Machida, Naoto Hirano, Takafumi Kasaya, Hidenori Kumagai

    OCEANS 2022　2022

    DOI： 10.1109/OCEANSChennai45887.2022.9775366 　

    ISSN： 0197-7385

  12. Modification for the matrix effect in SIMS-derived water contents of silicate glasses Peer-reviewed

    Kenji Shimizu, Takayuki Ushikubo, Takeshi Kuritani, Naoto Hirano, Shigeru Yamashita

    GEOCHEMICAL JOURNAL　56　(6)　223-230　2022

    DOI： 10.2343/geochemj.gj22019 　

    ISSN： 0016-7002

    eISSN： 1880-5973

  13. Cretaceous to Miocene NW Pacific Plate Kinematic Constraints: Paleomagnetism and Ar–Ar Geochronology in the Mineoka Ophiolite Mélange (Japan)

    Ariuntsetseg Ganbat, Daniel Pastor‐Galán, Naoto Hirano, Norihiro Nakamura, Hirochika Sumino, Yuji Yamaguchi, Tatsuki Tsujimori

    Journal of Geophysical Research: Solid Earth　126　(5)　2021/05/03

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1029/2020JB021492 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  14. Tokoro Belt (NE Hokkaido): an exhumed, Jurassic – Early Cretaceous seamount in the Late Cretaceous accretionary prism of northern Japan

    Shunta Sakai, Naoto Hirano, Yildirim Dilek, Shiki Machida, Kazutaka Yasukawa, Yasuhiro Kato

    Geological Magazine　158　(1)　1-12　2021/01/24

    DOI： 10.1017/S0016756819000633 　

    ISSN： 0016-7568

    eISSN： 1469-5081

  15. Multi‐approach characterization of shallow‐water carbonates off Minamitorishima and their depositional settings/history

    Md. Aftabuzzaman, Kazuki Yomogida, Shota Suzuki, Hideko Takayanagi, Akimasa Ishigaki, Shiki Machida, Yoshihiro Asahara, Koshi Yamamoto, Naoto Hirano, Shin‐Ichi Sano, Shun Chiyonobu, Davide Bassi, Yasufumi Iryu

    Island Arc　30　(1)　2021/01

    Publisher: Wiley

    DOI： 10.1111/iar.12400 　

    ISSN： 1038-4871

    eISSN： 1440-1738

  16. Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary

    Junji Yamamoto, Naoto Hirano, Mark D. Kurz

    Earth and Planetary Science Letters　552　2020/12/15

    DOI： 10.1016/j.epsl.2020.116611 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  17. Melting of recycled ancient crust responsible for the Gutenberg discontinuity

    Jia Liu, Naoto Hirano, Shiki Machida, Qunke Xia, Chunhui Tao, Shili Liao, Jin Liang, Wei Li, Weifang Yang, Guoying Zhang, Teng Ding

    Nature Communications　11　(1)　2020/12

    DOI： 10.1038/s41467-019-13958-w 　

    ISSN： 2041-1723

  18. Tectonic implications of carbonate deposits on the eastern slope of the Hahajima Seamount in the collision zone between the Izu–Bonin Arc on the Philippine Sea Plate and the Ogasawara Plateau on the Pacific Plate

    Jun Miyata, Hideko Takayanagi, Akimasa Ishigaki, Naoto Hirano, Satoshi Shiokawa, Akira Nishimura, Tsutomu Nakazawa, Tsuyoshi Ishikawa, Kazuya Nagaishi, Hidekazu Tokuyama, Akira Ishiwatari, Yasufumi Iryu

    Island Arc　29　(1)　2020/01/28

    DOI： 10.1111/iar.12368 　

    ISSN： 1038-4871

    eISSN： 1440-1738

  19. Alkali basalt from the Seifu Seamount in the Sea of Japan: post-spreading magmatism in a back-arc setting Peer-reviewed

    Naoto Hirano

    Solid Earth　11　(1)　23-36　2020/01/07

    DOI： 10.5194/se-11-23-2020 　

    ISSN： 1869-9529

    eISSN： 1869-9529

  20. Petit-spot volcanoes on the oldest portion of the Pacific plate Peer-reviewed

    Naoto Hirano

    Deep Sea Research Part I: Oceanographic Research Papers　154　103142-103142　2019/12

    DOI： 10.1016/j.dsr.2019.103142 　

    ISSN： 0967-0637

    eISSN： 1879-0119

  21. Rare earth elements and yttrium (REY) variability with water depth in hydrogenetic ferromanganese crusts

    Naoto Hirano

    Chemical Geology　493　224-233　2018/08

    DOI： 10.1016/j.chemgeo.2018.05.045 　

    ISSN： 0009-2541

  22. Direct ascent to the surface of asthenospheric magma in a region of convex lithospheric flexure Peer-reviewed

    Yuki Sato, Naoto Hirano, Shiki Machida, Junji Yamamoto, Masao Nakanishi, Teruaki Ishii, Arashi Taki, Kazutaka Yasukawa, Yasuhiro Kato

    International Geology Review　60　(10)　1231-1243　2018/07/27

    DOI： 10.1080/00206814.2017.1379912 　

    ISSN： 1938-2839 0020-6814

    eISSN： 1938-2839

  23. A quick report of R/V Hakuho KH18-2 cruise: lithospheric and asthenospheric composition of the Shikoku Basin Peer-reviewed

    Annual Meeting of the Geological Society of Japan　2018　2018

    DOI： 10.14863/geosocabst.2018.0_172 　

    ISSN： 1348-3935

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    [Program canceled for a disaster] Program canceled for the 2018 Hokkaido Eastern Iburi earthquake. However, This abstract is quotable and viewable on PDF.

  24. Electrical conductivity of old oceanic mantle in the northwestern Pacific I: 1-D profiles suggesting differences in thermal structure not predictable from a plate cooling model Peer-reviewed

    Naoto Hirano

    Earth, Planets and Space　69　111　2017/12

    DOI： 10.1186/s40623-017-0697-0 　

    ISSN： 1880-5981

    eISSN： 1880-5981

  25. Garnet xenocryst from petit-spot lavas as an indicator for off-axis mantle refertilization at intermediate spreading ridges Peer-reviewed

    Naoto Hirano

    Geology　45　(12)　1091-1094　2017/12/01

    DOI： 10.1130/g39427.1 　

    ISSN： 0091-7613

    eISSN： 1943-2682

  26. Relict chromian spinels in Tulu Dimtu serpentinites and listvenite, Western Ethiopia: implications for the timing of listvenite formation Peer-reviewed

    Ayano Sofiya, Akira Ishiwatari, Naoto Hirano, Tatsuki Tsujimori

    International Geology Review　59　(13)　1621-1631　2017/10/03

    DOI： 10.1080/00206814.2016.1213142 　

    ISSN： 0020-6814

    eISSN： 1938-2839

  27. Geochemical/Petrological Interactions between Subducting Lithosphere and Petit-spot Magmas Invited Peer-reviewed

    Naoto Hirano

    Journal of Geography (Chigaku Zasshi)　126　(2)　195-206　2017

    DOI： 10.5026/jgeography.126.195 　

    ISSN： 1884-0884

    eISSN： 1884-0884

  28. Petit-spot as definitive evidence for partial melting in the asthenosphere caused by CO 2 Peer-reviewed

    Machida, S., Kogiso, T., Hirano, N.

    Nature Communications　8　14302　2017

    DOI： 10.1038/ncomms14302 　

    ISSN： 2041-1723

  29. Geology and geochemistry of ferromanganese nodules in the Japanese Exclusive Economic Zone around Minamitorishima Island Peer-reviewed

    Machida, S., Fujinaga, K., Ishii, T., Nakamura, K., Hirano, N., Kato, Y.

    Geochemical Journal　50　(6)　539-555　2016

    DOI： 10.2343/geochemj.2.0419 　

    ISSN： 0016-7002

    eISSN： 1880-5973

  30. 歯舞群島と色丹島の地質資料と岩石試料の重要性

    平野直人, 油谷拓, 山本順司

    東北アジア研究　20　61-74　2016

  31. Submarine lava fields in French Polynesia Peer-reviewed

    Hirano, N., Nakanishi, M., Abe, N., Machida, S.

    Marine Geology　373　39-48　2016

    DOI： 10.1016/j.margeo.2016.01.002 　

    ISSN： 0025-3227

    eISSN： 1872-6151

  32. Pre-subduction metasomatic enrichment of the oceanic lithosphere induced by plate flexure Peer-reviewed

    Pilet, S., Abe, N., Rochat, L., Kaczmarek, M.-A., Hirano, N., Machida, S., Buchs, D.M., Baumgartner, P.O., Müntener, O.

    Nature Geoscience　9　(12)　898-+　2016

    DOI： 10.1038/ngeo2825 　

    ISSN： 1752-0894

    eISSN： 1752-0908

  33. Petit-spot geology reveals melts in upper-most asthenosphere dragged by lithosphere

    Shiki Machida, Naoto Hirano, Hirochika Sumino, Takafumi Hirata, Shigekazu Yoneda, Yasuhiro Kato

    EARTH AND PLANETARY SCIENCE LETTERS　426　267-279　2015/09

    DOI： 10.1016/j.epsl.2015.06.018 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  34. Petit-spot geology reveals melts in upper-most asthenosphere dragged by lithosphere Peer-reviewed

    Shiki Machida, Naoto Hirano, Hirochika Sumino, Takafumi Hirata, Shigekazu Yoneda, Yasuhiro Kato

    EARTH AND PLANETARY SCIENCE LETTERS　426　267-279　2015/09

    DOI： 10.1016/j.epsl.2015.06.018 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  35. The alkaline magmas intruded into the Nemuro Group

    Yutani Taku, Hirano Naoto

    Annual Meeting of the Geological Society of Japan　2015　95-95　2015

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2015.0_095 　

    ISSN： 1348-3935

    eISSN： 2187-6665

  36. Missing western half of the Pacific Plate: Geochemical nature of the Izanagi-Pacific Ridge interaction with a stationary boundary between the Indian and Pacific mantles Peer-reviewed

    Miyazaki, T., Kimura, J.-I., Senda, R., Vaglarov, B.S., Chang, Q., Takahashi, T., Hirahara, Y., Hauff, F., Hayasaka, Y., Sano, S., Shimoda, G., Ishizuka, O., Kawabata, H., Hirano, N., Machida, S., Ishii, T., Tani, K., Yoshida, T.

    Geochemistry, Geophysics, Geosystems　16　(9)　3309-3332　2015

    DOI： 10.1002/2015GC005911 　

    ISSN： 1525-2027

    eISSN： 1525-2027

  37. Melt-rich lithosphere-asthenosphere boundary inferred from petit-spot volcanoes Peer-reviewed

    Junji Yamamoto, Jun Korenaga, Naoto Hirano, Hiroyuki Kagi

    GEOLOGY　42　(11)　967-970　2014/11

    DOI： 10.1130/G35944.1 　

    ISSN： 0091-7613

    eISSN： 1943-2682

  38. The final equilibrium pressure and temperature for the primary petit-spot magma that erupted just before the outer rise in the northwestern Pacific.

    Machida Shiki, Kogiso Tetsu, Hirano Naoto

    Abstracts of Annual Meeting of the Geochemical Society of Japan　61　160-160　2014

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.61.0_160 　

  39. Carbon dioxide emission to Earth's surface by deep-sea volcanism Peer-reviewed

    Satoshi Okumura, Naoto Hirano

    GEOLOGY　41　(11)　1167-1170　2013/11

    DOI： 10.1130/G34620.1 　

    ISSN： 0091-7613

    eISSN： 1943-2682

  40. Petit-spot lava fields off the central Chile trench induced by plate flexure Peer-reviewed

    Naoto Hirano, Shiki Machida, Natsue Abe, Tomoaki Morishita, Akihiro Tamura, Shoji Arai

    GEOCHEMICAL JOURNAL　47　(2)　249-257　2013

    DOI： 10.2343/geochemj.2.0227 　

    ISSN： 0016-7002

    eISSN： 1880-5973

  41. 仙台付近の墓石 転倒率調査結果 Invited

    石渡明, 宮本毅, 平野直人

    東日本大震災を分析する, 第1巻, 地震・津波のメカニズムと被害の実態 (明石書店)　263-276　2013

  42. Conformity and precision of CO2 densimetry in CO2 inclusions: microthermometry versus Raman microspectroscopic densimetry Peer-reviewed

    Tomoyuki Kobayashi, Junji Yamamoto, Takao Hirajima, Hidemi Ishibashi, Naoto Hirano, Yong Lai, Vladimir S. Prikhod'ko, Shoji Arai

    JOURNAL OF RAMAN SPECTROSCOPY　43　(8)　1126-1133　2012/08

    DOI： 10.1002/jrs.3134 　

    ISSN： 0377-0486

  43. Retentivity of CO2 in fluid inclusions in mantle minerals Peer-reviewed

    Junji Yamamoto, Kazuhiko Otsuka, Hiroaki Ohfuji, Hidemi Ishibashi, Naoto Hirano, Hiroyuki Kagi

    EUROPEAN JOURNAL OF MINERALOGY　23　(5)　805-815　2011/10

    DOI： 10.1127/0935-1221/2011/0023-2150 　

    ISSN： 0935-1221

  44. Direct evidence for upper mantle structure in the NW Pacific Plate: Microstructural analysis of a petit-spot peridotite xenolith Peer-reviewed

    Yumiko Harigane, Tomoyuki Mizukami, Tomoaki Morishita, Katsuyoshi Michibayashi, Natsue Abe, Naoto Hirano

    EARTH AND PLANETARY SCIENCE LETTERS　302　(1-2)　194-202　2011/02

    DOI： 10.1016/j.epsl.2010.12.011 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  45. Petit-spot volcanism: A new type of volcanic zone discovered near a trench

    Naoto Hirano

    GEOCHEMICAL JOURNAL　45　(2)　157-167　2011

    DOI： 10.2343/geochemj.1.0111 　

    ISSN： 0016-7002

    eISSN： 1880-5973

  46. Role of plutonic and metamorphic block exhumation in a forearc ophiolite mélange belt: An example from the Mineoka belt, Japan Invited Peer-reviewed

    Ryota Mori, Yujiro Ogawa, Naoto Hirano, Toshiaki Tsunogae, Masanori Kurosawa, Tae Chiba

    Special Paper of the Geological Society of America　480　95-115　2011

    DOI： 10.1130/2011.2480(04) 　

    ISSN： 0072-1077

  47. 3-B12 Carbon emission from volcanoes

    Okumura Satoshi, Hirano Naoto

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2010　84-84　2010

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2010.0_84 　

    ISSN： 2433-5320

    eISSN： 2189-7190

  48. New insights into the oceanic lithosphere from petit-spot volcanoes and "Super-Mohole" project

    Hirano Naoto, Abe Natsue, Machida Shiki, Yamamoto Junji

    The Journal of the Geological Society of Japan　116　(1)　1-12　2010

    Publisher: The Geological Society of Japan

    DOI： 10.5575/geosoc.116.1 　

    ISSN： 0016-7630

    More details Close

    One of the mechanisms by which magma reaches the Earth’s surface is ascent along brittle fractures that develop where plates flex due to subduction and/or loading by seamounts, thereby forming a swarm of small knolls termed “petit-spots.” Such lavas are enriched in highly incompatible elements, suggesting an origin via partial melting of the asthenosphere. The widespread occurrence of this process is indicated by the discovery of small volcanoes (petit-spots) across broad regions of the NW Pacific plate and near the Tonga Trench, and is supported by a reinterpretation of the origin of alkaline basalts found within accretionary prisms. This paper provides new insights into the findings of Project Mohole based on investigations of petit-spots, as xenoliths entrained within petit-spot rocks, representing all types of geological material from the crust to the mantle, provide important information on old and subducting lithosphere of the NW Pacific plate. To complement this work, drilling undertaken as part of the proposed 21st Century Mohole project would represent a powerful tool in understanding the nature of young oceanic lithosphere. Thus, a study on petit-spot xenoliths, in conjunction with the 21st Century Mohole project (together constituting the Super Mohole Project), provides the opportunity to understand the nature of the entire oceanic lithosphere.

  49. Mechanisms of low-flux intraplate volcanic fields-Basin and Range (North America) and northwest Pacific Ocean Peer-reviewed

    Greg A. Valentine, Naoto Hirano

    GEOLOGY　38　(1)　55-58　2010/01

    DOI： 10.1130/G30427.1 　

    ISSN： 0091-7613

  50. Noble gas isotopic compositions of mantle xenoliths from northwestern Pacific lithosphere Peer-reviewed

    Junji Yamamoto, Naoto Hirano, Natsue Abe, Takeshi Hanyu

    CHEMICAL GEOLOGY　268　(3-4)　313-323　2009/11

    DOI： 10.1016/j.chemgeo.2009.09.009 　

    ISSN： 0009-2541

  51. Evidence for recycled plate material in Pacific upper mantle unrelated to plumes Peer-reviewed

    Shiki Machida, Naoto Hirano, Jun-Ichi Kimura

    GEOCHIMICA ET COSMOCHIMICA ACTA　73　(10)　3028-3037　2009/05

    DOI： 10.1016/j.gca.2009.01.026 　

    ISSN： 0016-7037

    eISSN： 1872-9533

  52. Knocker catalogue of the Mineoka ophiolite belt, Boso Peninsula, Japan

    Yujiro Ogawa, Ryota Mori, Naoto Hirano, AkikoTakahashi, Mia Mohammad Mohiuddin, Hiroshi Sato, Toshiaki Tsunogae, Masanori Kurosawa, Hidetsugu Taniguchi

    Earth Evolution Sciences, University of Tsukuba　3　3-25　2009/04

  53. Seamounts, knolls and petit-spot monogenetic volcanoes on the subducting Pacific Plate Invited Peer-reviewed

    Naoto Hirano, Anthony A. P. Koppers, Ayu Takahashi, Toshiya Fujiwara, Masao Nakanishi

    BASIN RESEARCH　20　(4)　543-553　2008/12

    DOI： 10.1111/j.1365-2117.2008.00363.x 　

    ISSN： 0950-091X

    eISSN： 1365-2117

  54. Origin of the asthenosphere

    Takahashi Eiichi

    Abstracts of Annual Meeting of the Geochemical Society of Japan　55　78-78　2008

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.55.0.78.0 　

  55. Three volcanic events on the NW Pacific Plate during Cretaceous to present

    HIRANO Naoto

    Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2007　18-18　2007/09/22

    Publisher: Japan Association of Mineralogical Sciences

    DOI： 10.14824/jakoka.2007.0.17.0 　

    ISSN： 1348-6543

    More details Close

    The volume of magma of the petit spot volcanoes (Hirano et al., 2006) has not been estimated but certainly must be several orders of magnitude less than surrounding Cretaceous volcanoes on the NW Pacific Plate. Note that we found 0-1, 2.5, 4.2, 6.0 and 8.6 Ma volcanoes, implying episodic eruption of magma over a distance of 600 km of plate motion on the flexural Pacific Plate before its subduction but with low volumes of magma production.

  56. Depleted mantle wedge and sediment fingerprint in unusual basalts from the Manihiki Plateau, central Pacific Ocean Peer-reviewed

    Stephanie Ingle, John J. Mahoney, Hiroshi Sato, Millard F. Coffin, Jun-Ichi Kimura, Naoto Hirano, Masao Nakanishi

    GEOLOGY　35　(7)　595-598　2007/07

    DOI： 10.1130/G23741A.1 　

    ISSN： 0091-7613

    eISSN： 1943-2682

  57. Subsurface structure of the "petit-spot'' volcanoes on the northwestern Pacific Plate Peer-reviewed

    Toshiya Fujiwara, Naoto Hirano, Natsue Abe, Kaoru Takizawa

    GEOPHYSICAL RESEARCH LETTERS　34　(13)　L13305　2007/07

    DOI： 10.1029/2007GL030439 　

    ISSN： 0094-8276

    eISSN： 1944-8007

  58. Noble gas and geochronology study of the Hana Ridge, Haleakala volcano, Hawaii; implications to the temporal change of magma source and the structural evolution of the submarine ridge Peer-reviewed

    Takeshi Hanyu, Kevin T. M. Johnson, Naoto Hirano, Zhong-Yuan Ren

    CHEMICAL GEOLOGY　238　(1-2)　1-18　2007/03

    DOI： 10.1016/j.chemgeo.2006.09.008 　

    ISSN： 0009-2541

    eISSN： 1872-6836

  59. Another nail in which coffin? Response

    Naoto Hirano, Anthony A. P. Koppers

    SCIENCE　315　(5808)　40-40　2007/01

    ISSN： 0036-8075

  60. Paleo-Moho depth determined from the pressure of CO2 fluid inclusions: Raman spectroscopic barometry of mantle- and crust-derived rocks Peer-reviewed

    Junji Yamamoto, Hiroyuki Kagi, Yoko Kawakami, Naoto Hirano, Masaki Nakamura

    EARTH AND PLANETARY SCIENCE LETTERS　253　(3-4)　369-377　2007/01

    DOI： 10.1016/j.epsl.2006.10.038 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  61. Volcanism in response to plate flexure Peer-reviewed

    Naoto Hirano, Eiichi Takahashi, Junji Yamamoto, Natsue Abe, Stephanie P. Ingle, Ichiro Kaneoka, Takafumi Hirata, Jun-Ichi Kimura, Teruaki Ishii, Yujiro Ogawa, Shiki Machida, Kiyoshi Suyehiro

    SCIENCE　313　(5792)　1426-1428　2006/09

    DOI： 10.1126/science.1128235 　

    ISSN： 0036-8075

  62. Petrology and geochemistry of mantle xenoliths from petit-spot volcano, NW Pacific Plate Peer-reviewed

    Natsue Abe, Junji Yamamo, Naoto Hirano, Shoji Arai

    GEOCHIMICA ET COSMOCHIMICA ACTA　70　(18)　A1-A1　2006/08

    DOI： 10.1016/j.gca.2006.06.016 　

    ISSN： 0016-7037

  63. O-154 Origin, tectonics and eruptive style of the petit spot volcano

    Hirano Naoto, Machida Shiki, Ishii Teruaki, Ingle Stephanie

    Annual Meeting of the Geological Society of Japan　2006　120-120　2006

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2006.0_120_1 　

  64. O-164 Mantle peridotites in the Western Pacific

    Ishii Teruaki, Hirano Naoto, Ohara Yasuhiko, Arima Makoto

    Annual Meeting of the Geological Society of Japan　2006　125-125　2006

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2006.0_125_1 　

  65. A35 Asthenospheric magmatism-1 : Crystallization, eruption and degassing process of newly found abyssal alkali basalt(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2006 FALL MEETING)

    Takehara Naoki, Takahashi Eiichi, Hirano Naoto

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2006　34-34　2006

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2006.0_34 　

  66. A36 Asthenosp heric magmatism-2 : Origin of alkali basalt on the old Pacific plate(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2006 FALL MEETING)

    Takahashi Eiichi, Takehara Naoki, Hirano Naoto

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2006　35-35　2006

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2006.0_35 　

  67. The chemical structure of the Hawaiian mantle plume Peer-reviewed

    ZY Ren, S Ingle, E Takahashi, N Hirano, T Hirata

    NATURE　436　(7052)　837-840　2005/08

    DOI： 10.1038/nature03907 　

    ISSN： 0028-0836

    eISSN： 1476-4687

  68. Late Eocene to early Miocene islans-arc on the Early Cretaceous to early Eocene oceanic plate along the Mineoka, Hayama and Setogawa Belt

    Hirano Naoto

    Annual Meeting of the Geological Society of Japan　2005　129-129　2005

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2005.0_129_2 　

    ISSN： 1348-3935

    eISSN： 2187-6665

  69. Noble gases in mantle-derived xenocrysts in an alkali basalt from Japan Trench oceanward slope Invited Peer-reviewed

    Yamamoto Junji, Hirano Naoto, Hanyu Takeshi, Kagi Hiroyuki, Kaneoka Ichiro

    Abstracts of Annual Meeting of the Geochemical Society of Japan　52　205-205　2005

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.52.0.205.0 　

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    We measured noble gas isotopic ratios of olivine xenocrysts in an alkali-basalt sampled from a northwest Pacific seamount. The xenocrysts are reported to be derived from upper-mantle from major element compositions. By applying both vacuum crushing and stepwise heating extraction of the noble gases, uncontaminated 3He/4He ratios range between 7.2 and 7.7 RA and 40Ar/36Ar ratios are up to 5000 in the xenocrysts. These observations demonstrate that the upper mantle beneath the oceanward slope of the Japan Trench has a similar isotopic composition to the MORB source, suggesting a uniform MORB source is largely distributed in the upper mantle.

  70. Young, olivine xenocryst-bearing alkali-basalt from the oceanward slope of the Japan Trench Peer-reviewed

    N Hirano, J Yamamoto, H Kagi, T Ishii

    CONTRIBUTIONS TO MINERALOGY AND PETROLOGY　148　(1)　47-54　2004/09

    DOI： 10.1007/s00410-004-0593-z 　

    ISSN： 0010-7999

  71. Construction of I-Xe and 40Ar-39Ar Dating System Using a Modified VG3600 Mass Spectrometer and the First I-Xe Data Obtained in Japan Peer-reviewed

    Noriko Ebisawa, Hirochika Sumino, Ryuji Okazaki, Yutaka Takigami, Naoto Hirano, Keisuke Nagao, Ichiro Kaneoka

    Journal of Mass Spectrometry Society of Japan　52　(4)　219-229　2004/04

    Publisher: The Mass Spectrometry Society of Japan

    DOI： 10.5702/massspec.52.219 　

    ISSN： 1340-8097

    More details Close

    Improvements in ion collectors of the VG3600 mass spectrometer used for 40Ar-39Ar dating in the Radioisotope Center, University of Tokyo, have been performed. We also constructed a new compact vacuum line for extraction and purification of noble gases, and connected it to the mass spectrometer. The new noble gas mass spectrometry system enables us to measure all noble gases (He, Ne, Ar, Kr, and Xe) at low detection limits corresponding to 2×10-15 cm3 STP or 5×103 atoms of Kr and Xe. A newly designed W-coil furnace effectively heats small samples (1-100 mg) in a Mo-crucible with condition of low blank levels (10-10 and 10-15 cm3 STP for Ar and Xe). Smaller sample sizes required for 40Ar-39Ar dating have reduced activity levels. The system was preliminarily applied to I-Xe dating of neutron irradiated meteorites, Bjurböle, Allende and Yamato-74191, and discovered a late formation age of Yamato-74191 (26 Ma after Bjurböle) compared with the Allende meteorite.

  72. A58 Volcanism in the east of Honshu about 150°E considered of the fresh alkali basalt recovered from the seaside wall of the Japan Trench

    Haraguchi Satoru, Hirano Naoto, Ogawa Yujiro, KR03-07 and KR04-08 cruise onboard scientists

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2004　59-59　2004

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2004.0_59 　

  73. A59 Kaiko Knolls at the Japan Trench : Anomalously young volcano on the Cretaceous Pacific Plate

    Hirano Naoto, Takahashi Eiichi, Takahashi Ayu, Umino Susumu, Ogawa Yujiro

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2004　60-60　2004

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2004.0_60 　

  74. A60 The Chemical Structure of the Hawaiian Mantle Plume

    Ren Z.-Y., Hirano N., Hirata T., Takahashi E.

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2004　61-61　2004

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2004.0_61 　

  75. Young alkali-basalt in the west Pacific with xenocryst from lithospheric mantle

    HIRANO Naoto

    Annual Meeting of the Geological Society of Japan　2003　160-160　2003

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2003.0_160_1 　

    ISSN： 1348-3935

    eISSN： 2187-6665

  76. Multi-stage evolution of the Tertiary Mineoka ophiolite, Japan: New geochemical and age constraints Invited Peer-reviewed

    N Hirano, Y Ogawa, K Saito, T Yoshida, H Sato, H Taniguchi

    OPHIOLITES IN EARTH HISTORY　218　279-298　2003

    DOI： 10.1144/GSL.SP.2003.218.01.15 　

    ISSN： 0305-8719

  77. The nature of faulting and deformation in the Mineoka ophiolite, NW Pacific Rim Invited Peer-reviewed

    A Takahashi, Y Ogawa, Y Ohta, N Hirano

    OPHIOLITES IN EARTH HISTORY　218　299-314　2003

    DOI： 10.1144/GSL.SP.2003.218.01.16 　

    ISSN： 0305-8719

  78. Occurrence of the sandstone included in the alkali-basalt lava flow from the western Mineoka Belt, Boso Peninsula, Japan, and its tectonic significance Peer-reviewed

    平野直人, 奥澤康一

    Journal of the Geological Society of Japan　108　(11)　691-700　2002/11

    Publisher: The Geological Society of Japan

    DOI： 10.5575/geosoc.108.11_691 　

    ISSN： 0016-7630

    eISSN： 1349-9963

    More details Close

    Sandstone xenoliths included in an alkali-basalt lava were discovered in the Toge area, western Mineoka Belt, Boso Peninsula, central Japan. The sandstone is composed of plagioclase, quartz, felsic volcanic rock fragments, and datolite of secondary replacement origin, and is thought to be identical to the Kamitsuka or Atagoyama Formation, Mineoka Group. The host alkali-basalt and associated picrite basalt show geochemical characteristics of within-plate type basalts, and are correlatable to the alkali-basalt of the same chemistry at Hegurinaka 5km SW which indicates 19.62±0.90 Ma Ar-Ar age. The occurrence of the sandstone implies that the alkali-basalts in the Mineoka Belt erupted near the convergent margin in the early Miocene time.

  79. Long-lived early Cretaceous seamount volcanism in the Mariana Trench, Western Pacific Ocean Peer-reviewed

    N Hirano, Y Ogawa, K Saito

    MARINE GEOLOGY　189　(3-4)　371-379　2002/09

    DOI： 10.1016/S0025-3227(02)00445-0 　

    ISSN： 0025-3227

  80. A new type of intra-plate volcanism; young alkali-basalts discovered from the subducting Pacific Plate, Northern Japan Trench Peer-reviewed

    N. Hirano, K. Kawamura, M. Hattori, K. Saito, Y. Ogawa

    Geophysical Research Letters　28　(14)　2719-2722　2001/07/15

    DOI： 10.1029/2000GL012426 　

    ISSN： 0094-8276

  81. O-6 Faulting history in the MOR-type basalt, Mineoka Belt, Boso Peninsula

    Takahashi A., Ogawa Y., Ohta Y., Hirano N.

    Annual Meeting of the Geological Society of Japan　2001　4-4　2001

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2001.0_4_2 　

  82. O-5 Occurrence and implications of alkali-basalt in the Mineoka Belt, central Japan

    HIRANO Naoto, OKUZAWA Koichi

    Annual Meeting of the Geological Society of Japan　2001　4-4　2001

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2001.0_4_1 　

    ISSN： 1348-3935

    eISSN： 2187-6665

  83. P-64 Ar-Ar ages of the Uyeda Ridge and its origin

    HIRANO Naoto, ISHII Teruaki, SAITO Kazuo

    Annual Meeting of the Geological Society of Japan　2000　239-239　2000

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.2000.0_239_1 　

  84. Tectonics of the Mineoka ophiolite based on the ages and chemistry of basalt

    HIRANO Naoto

    Annual Meeting of the Geological Society of Japan　1998　457-457　1998

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.1998.0_457 　

    ISSN： 1348-3935

    eISSN： 2187-6665

  85. ~<40>Ar/~<39>Ar age and chemistry of basalts in Mineoka Belt

    HIRANO Naoto, OGAWA Yujiro, SAITO Kazuo, YOSHIDA Takeyoshi

    Annual Meeting of the Geological Society of Japan　1997　221-221　1997

    Publisher: The Geological Society of Japan

    DOI： 10.14863/geosocabst.1997.0_221_1 　

Show all ︎Show first 5

Misc. 47

  1. Results of geochemical analysis and modeling of Mikuni et al. "Contribution of carbonatite and recycled oceanic crust to petit-spot lavas on the western Pacific Plate"

    Mikuni, K, Hirano, N, Machida, S, Sumino, H, Akizawa, N, Tamura, A, Morishita, T, Kato, Y

    EarthChem　2024

    DOI： 10.60520/IEDA/113084 　

  2. Carbonatite-induced petit-spot melts squeezed upward from the asthenosphere beneath the Jurassic Pacific Plate

    Kazuto Mikuni, Naoto Hirano, Shiki Machida, Hirochika Sumino, Norikatsu Akizawa, Akihiro Tamura, Tomoaki Morishita, Yasuhiro Kato

    2023/08/29

    Publisher: Copernicus GmbH

    DOI： 10.5194/egusphere-2023-1499 　

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    Abstract. The lithosphere–asthenosphere boundary (LAB), which can be seismically detected, stabilizes plate tectonics. Several conflicting hypotheses have been proposed as the causes of LAB discontinuity, such as the contribution of hydrated minerals, mineral anisotropy, and partial melts. The petit-spot melts ascending from the asthenosphere, owing to subducting plate flexures, support the partial melting at the LAB. Here, we observed the lava outcrops of six monogenetic volcanoes formed by petit-spot volcanism in the western Pacific. Thereafter, we determined the 40Ar/39Ar ages, major and trace element compositions, and Sr, Nd, and Pb isotopic ratios of the petit-spot basalts. The 40Ar/39Ar ages of two monogenetic volcanoes were ca. 2.6 Ma (million years ago) and ca. 0 Ma, respectively. The isotopic compositions of the western Pacific petit-spot basalts suggest their geochemically similar melting sources. They were likely derived from a mixture of high-μ (HIMU) mantle-like and enriched mantle (EM) -1-like components related to carbonatitic/carbonated materials and recycled crustal components. A mass balance-based melting model implied that the characteristic trace element composition (i.e., Zr, Hf, and Ti depletions) of the western Pacific petit-spot magmas could be explained by the partial melting of garnet lherzolite with a small degree of carbonatite melt flux with crustal components. This result confirms the involvement of carbonatite melt and recycled crust in the source of petit-spot melts and provides an implication for the genesis of tectonic-induced volcanism with similar geochemical signatures to those of petit-spots.

  3. X-ray diffraction intensities of the hydrothermal ferromanganese oxides obtained from a petit-spot volcano

    Azami, Keishiro, Shiki Machida, Naoto Hirano, Kentaro Nakamura, Kazutaka Yasukawa, Tetsu Kogiso, Masao Nakanishi, Yasuhiro Kato

    figshare　2023

    DOI： 10.6084/m9.figshare.22559851 　

  4. Rock and sediment dataset of petit-spots in the northwestern Pacific

    Norikatsu Akizawa, Naoto Hirano, Shiki Machida, Akira Ishikawa, Yuka Niwa, Gen Shimoda, Kazutaka Yasukawa, Kenji M. Matsuzaki, Chiori Tamura, Junji Kaneko

    Data in Brief　45　108764-108764　2022/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.dib.2022.108764 　

    ISSN： 2352-3409

  5. Editorial for the thematic issue, “Orogens, ophiolites, and oceans: A snapshot of Earth's tectonic evolution”

    Yasufumi Iryu, Tatsuki Tsujimori, Naoto Hirano, Yuji Ichiyama

    Island Arc　31　(1)　2022

    DOI： 10.1111/iar.12468 　

    ISSN： 1038-4871

    eISSN： 1440-1738

  6. 太平洋プレートの組成進化~海山・プチスポット・緑色岩

    平野 直人

    新地球　1　33-41　2020

  7. Quick report of the R/V Yokosuka and Shinkai 6500 YK16-01, YK19-05S Cruise-Preliminary 6K dive report on “petit-spot” volcano around Minamitorishima Island-

    石井輝秋, 金子誠, 町田嗣樹, 金子純二, 浅見慶志朗, 平野直人, 秋澤紀克, 松本亜沙子, 田中えりか, 油谷拓, 進士優朱輝, 小長谷智哉, 長谷川貴章, 木野聡志, 大嶋ちひろ, 坂本衣里, 井和丸光

    深田地質研究所年報　(21)　2020

  8. Quick report of the R/V Shinsei-maru KS-18-9 dredge cruise on petit-spot volcanoes : Historical great discovery : explosion crater (Maar) in the Pacific abyssal plane, off Tohoku

    (20)　105-128　2019

    Publisher: 深田地質研究所

  9. 未知のマグマ活動の成因を探る～根室半島と歯舞群島

    平野直人

    Arctic Circle　99　2016

    Publisher: 一般財団法人北方文化振興協会

  10. 海洋プレートの進化と海底火山を理解するためのAr–Ar年代測定

    平野直人

    アイソトープ総合センターニュース　42　(1)　10-16　2011

    Publisher: 東京大学アイソトープ総合センター

  11. New kind of volcano on the Earth ―Geochronological studies of neutron-irradiated lavas erupted on the sea floor―

    Naoto Hirano

    KINKEN Research Highlights　2011　77-77　2011

    Publisher: Institute for Materials Research, Tohoku University

  12. Massive basalt flows on the southern flank of Tamu Massif, Shatsky Rise: a reappraisal of ODP Site 1213 basement units

    Anthony A.P. Koppers, Takashi Sano, James H. Natland, Mike Widdowson, Renat Almeev, Andrew R. Greene, David T. Murphy, Adelie Delacour, Masaya Miyoshi, Kenji Shimizu, S. Li, Naoto Hirano, Joerg Geldmacher, Expedition, Scientists

    Proceedings of the IODP volume 324　2010

    DOI： 10.2204/iodp.proc.324.109.2010 　

  13. Petit-spot volcanoes off the Chile & Tonga Trench

    Hirano Naoto, Machida Shiki, Abe Natsue

    Abstracts of Annual Meeting of the Geochemical Society of Japan　57　154-154　2010

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.57.0.154.0 　

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    The new kind of volcanoes, petit-spot, is monogenetic and young volcano discovered on the Cretaceous NW Pacific Plate, where the outer-rise forms during subduction when old and cold lithosphere bends so that it can sink into the interior of the Earth at the trenches. I would show the possible sites of the petit-spot volcanic activities at the oceanward slopes of the Japan, Chile and Tonga trenches, which are good examples of fracture-related petit-spot volcanoes. Pending more detailed rock sampling at the ocean-ward slope of the trenches and the age dating of lavas, we anticipate that petit-spot volcanic activity is an ubiquitous phenomenon on all flexed parts of all subducting tectonic plates globally.

  14. Geochemistry of Alkaline Basalts from Petit-spot Volcanoes in the Northwestern Pacific

    Machida Shiki, Hirano Naoto, Kato Yasuhiro, Abe Natsue

    Abstracts of Annual Meeting of the Geochemical Society of Japan　57　18-18　2010

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.57.0.18.0 　

  15. Overview of the MR08-06 Leg1 Marine Geology and Geophysical Research: A complete cross-Ocean Hemisphere Cruise

    ABE Natsue, Fujiwara Toshiya, Kanamatsu Toshiya, Suetsugu Daisuke, Yamazaki Toshitsugu, Iwamori Hikaru, Anma Ryo, Hirano Naoto, Orihashi Yuji, Harada Naomi

    Abstracts of Annual Meeting of the Geochemical Society of Japan　57　189-189　2010

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.57.0.189.0 　

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    A complete trans-Pacific cruise, MR08-06 Leg1, was conducted in January-March 2009 from Sekinehama, Japan to Valparaiso, Chile via Papeete, Tahiti, as a part of SORA 2009 (South Pacific Ocean Research Activity 2009) by JAMSTEC R/V MIRAI, which is a half year cruise in the Pacific Ocean. The main objectives of MR08-06 Leg1 are geological and geophysical surveys in the broad ocean basin, so to say ocean-hemisphere.

  16. Petit-spot volcanoes scraped off into accretionary wedge

    Hirano Naoto

    Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2010　3-3　2010

    Publisher: Japan Association of Mineralogical Sciences

    DOI： 10.14824/jakoka.2010.0.3.0 　

    ISSN： 1348-6543

    More details Close

    New of the mechanisms by which magma reaches the Earth's surface is ascent along brittle fractures that develop where plates flex due to subduction and/or loading by seamounts, thereby forming a swarm of small knolls termed "petit-spots". The widespread occurrence of this process is supported by the reinterpretation of the origin of alkaline basalts found within accretionary prisms.

  17. Knocker catalogue of the Mineoka ophiolite belt, Boso Peninsula, Japan

    Ogawa, Y., Mori, R., Hirano, N., Takahashi, A., Mohiuddin, M.M., Sato, H., Tsunogae, T., Kurosawa, M., Taniguchi, H., Chiba, A.T.

    Earth Evolution Sciences　3　3-25　2009/03/31

    ISSN： 1881-8463

  18. Physical properties in the asthenosphere beneath the petit-spot region inferred from BBOBS data

    SHITO Azusa, SUGIOKA Hiroko, ITO Aki, BABA Kiyoshi, ABE Natsue, HIRANO Naoto, SHIOBARA Hajime, KANAZAWA Toshihiko

    Blue Earth要旨集　2009　2009

  19. Evidence for recycled plate material in Pacific upper mantle unrelated to plumes

    Machida Shiki, Hirano Naoto, Kimura Jun-Ichi

    Abstracts of Annual Meeting of the Geochemical Society of Japan　56　284-284　2009

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.56.0.284.0 　

  20. プチスポット活動にかかわる熱流量の研究

    濱元栄起, 山野誠, 馬場聖至, 阿部なつ江, 平野直人, 高橋亜夕

    しんかいシンポジウム予稿集　24th　2008

  21. 北西太平洋の新種火山「プチスポット」の総合調査:メルト生成場とマグマ噴出場の分布解明

    馬場聖至, 阿部なつ江, 平野直人, 町田嗣樹, 石井輝秋, 山本順司, 山野誠, 濱元栄起, 杉岡裕子, 志藤あずさ, 伊藤亜妃, 高橋亜夕, 富士原敏也, 中西正男, 小池悠己, 小池悠己, 磯部太祐, 吉田貴洋

    しんかいシンポジウム予稿集　24th　2008

  22. What is the supra-subduction ophiolite or forearc ophiolite?: Examples from the Mineoka belt and constraints from the Izu-Mariana arc

    Ogawa Yujiro, Kurosawa Masanori, Hirano Naoto, Mori Ryota

    Abstracts of Annual Meeting of the Geochemical Society of Japan　55　303-303　2008

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.55.0.303.0 　

  23. プチスポット総合調査—Multidisciplinary investigation of petit spot—総特集 海洋プレートと島弧の深部構造(1)IODP超深度掘削へ向けて ; プチスポット

    馬場 聖至, 阿部 なつ江, 平野 直人

    月刊地球 = Chikyu monthly / 月刊地球編集部 編　29　(9)　548-553　2007/09

    Publisher: 日野 : 海洋出版

    ISSN： 0387-3498

  24. 北西太平洋で発見された新種の火山--プチスポット火山—A new kind of volcano, petitspot, discovered on the NW Pacific Plate—総特集 海洋プレートと島弧の深部構造(1)IODP超深度掘削へ向けて ; プチスポット

    平野 直人

    月刊地球 = Chikyu monthly / 月刊地球編集部 編　29　(9)　540-547　2007/09

    Publisher: 海洋出版

    ISSN： 0387-3498

  25. 北西太平洋で発見された新種の火山－プチスポット火山－

    平野直人

    月刊地球　29　(9)　540-547　2007/09

    Publisher: 海洋出版

  26. プチスポット総合調査

    馬場聖至, 阿部なつ江, 平野直人, 富士原敏也, 市來雅啓, 町田嗣樹, 高橋亜夕, 山本順司, 山野誠, 濱元栄起, 杉岡裕子, 志藤あずさ

    月刊地球　29　(9)　548-553　2007/09

    Publisher: 海洋出版

  27. プチスポット産アルカリ玄武岩の同位体組成が示す北西太平洋上部マントルの不均質性

    町田嗣樹, 平野直人, 木村純一

    月刊地球　29　(9)　554-560　2007/09

    Publisher: 海洋出版

    ISSN： 0387-3498

  28. プチスポット海底火山 ～新種の火山の発見～

    平野直人

    JGL　3　(2)　6-8　2007/05

    Publisher: 日本地球惑星科学連合

    ISSN： 1880-4292

  29. Noble gas and geochronology study of the Hana Ridge, Haleakala volcano, Hawaii; implications to the temporal change of magma source and the structural evolution of the submarine ridge

    Takeshi Hanyu, Kevin T. M. Johnson, Naoto Hirano, Zhong-Yuan Ren

    CHEMICAL GEOLOGY　238　(1-2)　1-18　2007/03

    DOI： 10.1016/j.chemgeo.2006.09.008 　

    ISSN： 0009-2541

    eISSN： 1872-6836

  30. Response [3]

    Hirano, N., Koppers, A.A.P.

    Science　315　(5808)　40　2007/01/05

    ISSN： 0036-8075

  31. 海洋プレートと島弧の深部構造-IODP超深度掘削へ向けて-プチスポット総合調査

    馬場聖至, 阿部なつ江, 平野直人, 富士原敏也, 市來雅啓, 町田嗣樹, 高橋亜夕, 山本順司, 山野誠, 濱元栄起, 杉岡裕子, 志藤あずさ

    月刊地球　29　(9)　2007

    ISSN： 0387-3498

  32. 北西太平洋の新種火山「プチスポット」の総合調査:メルト生成場とマグマ噴出場の分布解明

    馬場聖至, 阿部なつ江, 平野直人, 杉岡裕子, 志藤あずさ, 町田嗣樹, 濱元栄起, 伊藤亜紀, 高橋亜夕, 吉田貴洋, 磯部大祐, 小池悠己, 石井輝秋

    海洋研究開発機構航海概要報告書&運航実績一覧&航跡図&運航線表(CD-ROM)　2007　2007

  33. Asthenosphere under petitspot volcanoes, NW Pacific Plate

    Hirano Naoto, Yamamoto Junji, Machida Shiki

    Abstracts of Annual Meeting of the Geochemical Society of Japan　54　84-84　2007

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.54.0.84.0 　

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    Newly found volcanoes, petitspot, on the Cretaceous NW Pacific Plate are monogenetic volcanic edifices where the melt escaped from asthenosphere to the surface (Hirano et al., 2006, Science). Volcanic materials of the petitspot, therefore, are anticipated to show the chemical composition of the asthenospheric mantle. Here we show the geochemical composition of petitspot lavas in order to know the composition of the asthenosphere under the NW Pacific Plate.

  34. プチスポット玄武岩の同位体組成が示す、プルームに関連しない太平洋上部マントルの不均質性

    町田 嗣樹, 平野 直人, 木村 純一

    日本地球化学会年会要旨集　54　85-85　2007

    Publisher: 一般社団法人日本地球化学会

    DOI： 10.14862/geochemproc.54.0.85.0 　

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    近年、日本海溝海側斜面および北西太平洋の古い太平洋プレート上に、新しいタイプの若い火山（プチスポット）が発見された。本発表では、若い火山から得られた微量元素に富む未分化なアルカリ玄武岩のSr、Nd、Pb同位体組成を報告する。アルカリ玄武岩は、南半球（インド洋や大西洋）の中央海嶺玄武岩や海洋島玄武岩と同様のSr、Nd、Pb同位体組成（DUPAL異常）を示し、EM1マントル端成分の組成に極めて近い。この事実は、マントルプルームの影響のないノーマルな北半球の太平洋型マントルにも、リサイクルされたプレート物質による不均質性が存在することの証拠である。

  35. Depleted mantle wedge and sediment fingerprint in unusual basalts from the Manihiki plateau, central Pacific Ocean: Reply

    Stephanie Ingle, John J. Mahoney, Hiroshi Sato, Millard F. Coffin, Jun-Ichi Kimura, Naoto Hirano, Masao Nakanishi

    Geology　35　(1)　e165　2007

    Publisher: Geological Society of America

    DOI： 10.1130/G24882Y.1 　

    ISSN： 1943-2682 0091-7613

  36. Paleo-Moho depth determined from the pressure of CO2 fluid inclusions: Raman spectroscopic barometry of mantle- and crust-derived rocks

    Junji Yamamoto, Hiroyuki Kagi, Yoko Kawakami, Naoto Hirano, Masaki Nakamura

    EARTH AND PLANETARY SCIENCE LETTERS　253　(3-4)　369-377　2007/01

    DOI： 10.1016/j.epsl.2006.10.038 　

    ISSN： 0012-821X

    eISSN： 1385-013X

  37. Another nail in which coffin? Response

    Marcia McNutt

    SCIENCE　315　(5808)　40-40　2007/01

    DOI： 10.1126/science.315.5808.39c 　

    ISSN： 0036-8075

  38. 40Ar‐39Ar法による岩石・鉱物の年代測定

    SAITO KAZUO, IWATA NAOYOSHI, SATO YOSHIKO, HANYU TAKESHI, HIRANO NAOTO

    東北大学金属材料研究所附属量子エネルギー材料科学国際研究センター共同利用研究経過報告書(CD-ROM)　22nd　ROMBUNNO.IV.-6.　2006/06

  39. 東アジア‐日本海‐東北日本弧‐北西太平洋を横断する1次元電気伝導度構造の傾向

    市来雅啓, 阿部なつ江, 後藤忠徳, 馬場聖至, 歌田久司, 上嶋誠, 金沢敏彦, 望月公広, 山田知朗, 藤浩明, 平野直人, 小川康雄, 三品正明

    しんかいシンポジウム予稿集　22nd　157-158　2006/02

  40. Noble gas recycling in the Izu-Ogasawara arc

    Shimizu Aya, Sumino Hirochika, Nagao Keisuke, Notsu Kenji, Hirano Naoto, Machida Shiki, Ishii Teruaki

    Abstracts of Annual Meeting of the Geochemical Society of Japan　53　211-211　2006

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.53.0.211.0 　

  41. Relation between partial melting of ultrahigh-temperature metamorphic rocks and sapphirine formation

    Sato Kei, Hirano Naoto, Hirata Takafumi

    Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists　2005　106-106　2005

    Publisher: Japan Association of Mineralogical Sciences

    DOI： 10.14824/jampeg.2005.0.106.0 　

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    Sapphirine is one of the major minerals ubiquitously found in ultrahigh-temperature (UHT) metamorphic rocks. Mineral assemblage of sapphirine + quartz was found in metamorphic rocks from Napier Complex, East Antarctica [1], and this paragenesis of the two minerals implies a possibility of extreme high-grade metamorphic conditions as follows: >1030&deg;C at 9.5 kbar [2] or: >1050&deg;C at 11 kbar [3]. Sapphirine is recognized as an important phase, which suggests UHT condition; however, nucleation and growths processes have not been well understood.Our research group with Dr. T. Miyamoto and Prof. T. Kawasaki experimentally demonstrated sapphirine formation in the system of UHT granulite (sample no. TM981229-03E; [4]) from the Napier Complex. The granulite sample is almost H2O-free; and it contains mineral assemblages of "sapphirine corona including spinel grains" and "sapphirine + quartz". This experiment revealed that sapphirine formed at around 1100&deg;C and 9 kbar under decreasing temperature condition through series of reactions: (1) spinel + melt = orthopyroxene + sapphirine; (2) spinel + melt = fluorphlogopite + sapphirine; and: (3) orthopyroxene + spinel + melt = sapphirine [5 and 6]. The molten phases showed granitic composition. The results mean that the sapphirine is a reaction product, which is crystallized under retrograde metamorphic condition. Moreover, it is also implied that molten phase, which is partially generated from UHT metamorphic rocks, is not completely segregated from its bulk; and the residual melt is essential for the sapphirine formation in the granulite system.Grew et al. [7] pointed out that the distribution of trace elements in sapphirine could be used as a significant indicator for investigations of the partial melting. In order to understand that, we are conducting determination of minor elements of the sapphirine and other phase's in the granulite using an ICP-MS coupled with a laser ablation system at Tokyo Institute of Technology. Thus, it is expected that our analytical results should also give new information of that. In the presentation, we'll discuss genetic relationship between molten phase and sapphirine in the UHT granulite system, based on major and trace elements distributions in the sapphirine and other phases.References: [1] Dallwitz, Nature, 219 (1968) 476-477; [2] Hensen and Green, Contrib. Mineral. Petrol., 38 (1973) 151-166; [3] Bertrand et al., Contrib. Mineral. Petrol., 108 (1991) 55-71; [4] Miyamoto et al., Polar Geosci., 17 (2004) 88-111; [5] Sato et al., J. Mineral. Petrol. Sci., 99 (2004) 191-201; [6] Sato et al., Abst. 24th Symp. Antarct. Geosci. NIPR (2004) pp. 87 (in Japanese); [7] Grew et al., Abst. 24th Symp. Antarct. Geosci. NIPR (2004) 27-28.

  42. Magma process and origin of young volcanisms on the Early Cretaceous Pacific Plate

    Hirano Naoto, Yamamoto Junji, Takahashi Eiichi, Abe Natsue, Ishii Teruaki

    Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists　2005　12-12　2005

    Publisher: Japan Association of Mineralogical Sciences

    DOI： 10.14824/jampeg.2005.0.12.0 　

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    Anomalously young volcanoes, of approximately 6, 4 and 1 Ma in age, for the 130-135 Ma Pacific Plate were discovered form the toe of the oceanward slope of the northern Japan Trench [1] and the abyssal plain on the Northwestern Pacific Basin. The new bathymetric, geological and petrological data indicate two types of eruptive style, different in the degree of vesicularity and major element composition; one is very vesicular lava forming knolls, another is dense lava forming sheet flows. The distributions of these volcanoes clearly have the trend of WNW to ESE, which are perpendicular to the hinge line of the flexural lithosphere (outer-rise) due to plate-subduction.The lavas are trapped some xenoliths of basalts, gabbros and peridotites, which are likely oceanic crust and lithospheric mantle in origin. Two types of olivine are also present in these lavas, xenocrysts with reaction rims and magmatic. The forsterite (Fo) (#91-92) values and NiO contents (0.3-0.5 wt%) of the xenocrysts are similar in composition to those of the depleted mantle peridotite. Chromian spinel inclusions in the xenocrysts also show the depleted composition in the range of abyssal peridotite. These data indicate that the xenocrysts originate from MORB-depleted mantle [2]. The calculated primitive magma, on the other hand, follows a low degree of partial melting along the 2.5 to 3 GPa cotectic lines, which would corresponds the depth of asthenosphere.The ascending magma from asthenosphere, therefore, would trap some xenoliths and xenocrysts originating in the conduit wall, possibly when brittle fractures occurs in the upper lithosphere due to the concave flexure of the plate in front of the convex bowing of outer-rise. The eruption occurred along some fissures being bent before subduction, in parallel to the maximum horizontal compression due to the down-warping of the Pacific plate motion for sub-crustal magma injection.

  43. Geochemical evidence for the origin of young volcanisms on the Early Cretaceous Pacific Plate

    Hirano Naoto, Yamamoto Jyunji, Takahashi Eiichi, Kaneoka Ichiro, Hirata Takafumi

    Abstracts of Annual Meeting of the Geochemical Society of Japan　52　(0)　208-208　2005

    Publisher: GEOCHEMICAL SOCIETY OF JAPAN

    DOI： 10.14862/geochemproc.52.0.208.0 　

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    沈み込む古いプレート上で活動する新しいタイプの火山活動が発見されて以来、地球上の新しいタイプの火山として注目されている。本研究ではこの火山の成因を、噴出玄武岩の主要元素成分および微量元素成分、希ガス同位体組成を用いた地球化学的証拠から解明した。

  44. Multi-stage evolution of the Tertiary Mineoka ophiolite, Japan: New geochemical and age constraints

    N Hirano, Y Ogawa, K Saito, T Yoshida, H Sato, H Taniguchi

    OPHIOLITES IN EARTH HISTORY　218　279-298　2003

    DOI： 10.1144/GSL.SP.2003.218.01.15 　

    ISSN： 0305-8719

  45. The nature of faulting and deformation in the Mineoka ophiolite, NW Pacific Rim

    A Takahashi, Y Ogawa, Y Ohta, N Hirano

    OPHIOLITES IN EARTH HISTORY　218　299-314　2003

    DOI： 10.1144/GSL.SP.2003.218.01.16 　

    ISSN： 0305-8719

  46. 嶺岡オフィオライトの起源

    佐藤暢, 谷口英嗣, 高橋直樹, Mia Mohammad, MOHIUDDIN, 平野直人, 小川勇二郎

    Journal of Geography, Geographical Society of Tokyo　108　(3)　203-215　1999/03

    DOI： 10.5026/jgeography.108.203 　

  47. 放射年代と化学組成に基づく嶺岡帯中の火成岩の起源

    平野直人

    筑波大学博士課程地球科学研究科修士論文　123　1998

Show all ︎Show first 5

Books and Other Publications 3

  1. 東北アジアの自然と文化 2

    東北大学東北アジア研究センター

    東北大学出版会　2023/01

    ISBN: 9784861633737

  2. 大陸と日本をつなぐ自然史 : 地質・生態系の総合研究最前線

    鹿野, 秀一, 平野, 直人, 千葉, 聡

    古今書院　2021/01

    ISBN: 9784772253123

  3. 東北アジアの自然と文化

    東北大学東北アジア研究センター

    東北大学出版会　2018/03

    ISBN: 9784861632952

Presentations 83

  1. How to occur the melt at the lithosphere–asthenosphere boundary: Insights from geochemical perspective on petit-spot lavas

    Kazuto Mikuni, Naoto Hirano

    AGU 2024 Fall Meeting　2024/12/11

  2. Cretaceous hotspots, Eocene non?-hotspot, and petit-spots on the Western Pacific plate

    Naoto Hirano, Kazuto Mikuni, Yuya Jindo, Shiki Machida

    AGU 2024 Fall Meeting　2024/12/09

  3. 沈み込む帯へのインプット直前の太平洋プレート構成岩石

    平野直人, 神藤裕哉, 三國和音

    地球惑星科学連合2024年大会　2024/05/27

  4. 西太平洋海山群に存在する若いホットスポット海山列の探索

    神藤裕哉, 平野直人, 町田嗣樹

    地球惑星科学連合2024年大会　2024/05/27

  5. 地球深部探査船「ちきゅう」によるプチスポットパイプのライザーレス掘削で海洋マントル採取に挑もう

    石井輝秋, 平野直人, 秋澤紀克, 金子誠, 町田嗣樹

    地球惑星科学連合2024年大会　2024/05/27

  6. プチスポット玄武岩から見る北西太平洋プレート下の揮発性成分

    佐野真, 平野直人, 奥村聡, 秋澤紀克, 田村明弘, 森下知晃

    地球惑星科学連合2024年大会　2024/05/27

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    学生優秀発表賞

  7. 北西太平洋プチスポット玄武岩のPb-Sr-Nd同位体組成からみる上部マントル不均質

    中野泰紀, 平野直人, 町田嗣樹

    地球惑星科学連合2024年大会　2024/05/27

  8. Mantle heterogeneity beneath the NW Pacific Plate investigated using volatile and trace element compositions of petit-spot basalts

    佐野真, 平野直人, 奥村聡, 秋澤紀克, 田村明弘, 森下知晃

    日本地球化学会年会要旨集(Web)　2024/09/18

  9. Evolution of the Pacific plate: its submarine geology, oceanic crust, and suboceanic mantle

    平野直人, 町田嗣樹, 秋澤紀克

    日本地球化学会年会要旨集(Web)　2024/09/18

  10. EM1 component beneath petit-spot: the source material of non-plume EM1

    中野泰紀, 平野直人, 町田嗣樹

    日本地球化学会年会要旨集(Web)　2024/09/18

  11. プチスポット海底火山

    平野直人

    第199回 深田研談話会　2023/11/10

  12. 疑似モホール計画：プチスポット火山産海洋地殻・マントル捕獲岩はマントル掘削の先駆けとなりうるか

    三國和音, 平野直人, 町田嗣樹, 秋澤紀克, 田村明弘, 森下知晃

    日本地球化学会 第70回年会　2023/09/21

  13. プチスポット火山によるアセノスフェア～海底表層リンケージ.

    平野直人, 秋澤紀克, 三國和音, 町田嗣樹

    海底拡大系観測から探る地球内部と表層のリンケージ～InterRidge-Japan研究集会～　2023/06/19

  14. 深海底におけるプチスポット火山の噴火様式 Invited

    平野直人, 三國和音, 町田嗣樹

    地球惑星科学連合2023年大会　2023/05/24

  15. カーボナタイトフラックスに起因するアセノスフェア部分溶融およびプチスポットマグマのリソスフェアへのインプット

    三國和音, 平野直人, 秋澤紀克, 町田嗣樹, 角野浩史, 田村明弘, 森下知晃

    地球惑星科学連合2023年大会　2023/05/22

  16. 嶺岡帯玄武岩の年代測定と古地磁気観測によるテクトニクスの復元

    平野直人

    AORI共同利用研究集会: フィリピン海プレート北端部テクトニクスの再検討　2022/11/28

  17. 美濃帯犬山セクションの層状チャートに貫入する塩基性・超塩基性岩脈の意義

    新保陽輔, 平野直人, 秋澤紀克, 角野浩史

    日本地質学会第129年学術大会　2022/09/04

  18. プチスポット火山がもたらすケイ長質捕獲岩：太平洋プレート最古部の海洋地殻物質断片

    三國和音, 平野直人, 秋澤紀克, 町田嗣樹

    日本地質学会第129年学術大会　2022/09/04

  19. プレート沈み込み手前で発生するプチスポット火山が引き起こす地質擾乱・マントル交代作用

    平野直人, 三國和音, 新保陽輔, 秋澤紀克, 町田嗣樹

    日本地球惑星科学連合2022大会　2022/05/26

  20. 西太平洋海山群におけるホットスポット海山列の検証

    神藤裕哉, 平野直人, 町田嗣樹, 森下泰成, 角野浩史

    日本地球惑星科学連合2022大会　2022/05/26

  21. 北海道東部太平洋側の特異な地質基盤に起因する植生・気候・文化・産業

    平野直人, 山本順司

    日本地球惑星科学連合2022大会　2022/05/25

  22. Process of hydrothermal activity estimated from independent component analysis

    浅見慶志朗, 町田嗣樹, 平野直人, 中村謙太郎, 安川和孝, 小木曽哲, 加藤泰浩, 加藤泰浩

    日本地質学会学術大会(Web)　2022

  23. Characteristics of petit-spot basalts based on comparison of element compositions with EM-1 intraplate basalts

    Shimbo Yosuke, Hirano Naoto

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

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    Petit-spot basalts are geochemically classified as oceanic island basalts (OIBs) influenced by the EM-1 component. The regional differences in trace element compositions of EM-1 OIBs provide clues to the heterogeneity of mantle and the conditions of origin of petit-spot magmas. In this study, the whole-rock trace element compositions of the world EM-1 OIBs are performed by principal component analysis to find characteristic elemental behaviors using the multidimensional elemental data. The selected principal components suggest that many hot spot volcanoes and some petit spot volcanoes are affected by different principal components. Petit-spot volcanoes on the NW Pacific Plate, Site C, were strongly influenced by both principal components. The relatively diverse compositions even in the same area suggest that petit-spot magmas originate from small-scale and heterogeneous mantle.

  24. Evolution of the Pacific Plate: An investigation of subducting plate

    Hirano Naoto, Machida Shiki, Akizawa Norikatsu

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

  25. Comparison of noble gas and CO2 compositions of petit-spot lava and mid-ocean ridge basalt

    Obase Tomoya, Sumino Hirochika, Hirano Naoto, Machida Shiki

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

  26. Ar-Ar and U-Pb ages of petit-spot volcanic cluster on the subducting Pacific Plate

    Hirano Naoto, Sumino Hirochika, Iwano Hideki, Danhara Toru, Hirata Takafumi

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

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    Submarine petit-spot magmatisms induced by lithospheric flexure provide some injections into old lithosphere and submarine environment near trench prior to its subduction. Although Ar-Ar age estimates were poorly constrained for lava samples because of recoil and excess Ar, eight holocrystalline samples provide the good plateau ages. In a further attempt to determine the age of the lavas, we separated zircon crystals from peperite samples, which show upper limit of eruption age. Older zircons, moreover, were dated at various ages all younger than the crustal age, implying submarine sediments were annealed and highly disturbed due to the petit-spot magma. Our Ar-Ar and U-Pb age data of lavas and peperites provide a new understanding of the lithosphere and submarine environment of the NW Pacific Plate.

  27. High-resolution acoustic survey of Petit Spot volcano using the submersible SHINKAI 6500

    Kaneko Junji, Machida Shiki, Hirano Naoto, Kasaya Takafumi, Kumagai Hidenori

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

  28. Sr, Nd, and Pb isotopic compositions and Ar-Ar ages of Western Pacific Seamount Province

    Jindo Yuya, Hirano Naoto, Machida Shiki, Morishita Taisei, Sumino Hirochika

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

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    Recently, some Paleogene Ar-Ar ages were recently reported at Minamitorishima Island, the Chuo Seamount on Ogasawara Plateau and Uyeda Ridge located in the Western Pacific Seamounts Province (WPSP) which is an area recognized as group of short-lived Cretaceous hotspot tracks. Although the Ogasawara Plateau and Minamitorishima Island were already formed in Early Cretaceous, it is impossible to recognize as a continuous eruption since Early Cretaceous because of their too long hiatus. In this study, we analyzed acid-leached Sr, Nd, Pb isotopic composition and calculated the eruptive region based on Ar-Ar ages of the Paleogene lava sample to discuss the origin of the magma. The samples from four seamounts of the Cretaceous hotspot seamount trails (N-Wake) were simultaneously analyzed as well. The Paleogene samples from Minamitorishima Island and Chuo Seamount are clearly discriminated from the Cretaceous hotspot seamounts in both isotopic composition and eruptive site .

  29. Influence of hydrothermal alteration on oceanic crust by petit-spot volcanos

    Azami Keishiro, Machida Shiki, Hirano Naoto, Kogiso Tetsu, Nakamura Kentaro, Kato Yasuhiro

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

  30. Geochemical characteristics of petit-spot volcanoes on the western Pacific Plate

    Mikuni Kazuto, Hirano Naoto, Machida Shiki, Sumino Hirochika, Akizawa Norikatsu, Tamura Akihiro, Morishita Tomoaki, Kato Yasuhiro

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2022/09/07

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    Petit-spot, the fourth kind of universal volcanic activity on the Earth after island arcs, mid ocean ridges, and hotspots, is expected to originate from the lithosphere-asthenosphere boundary. Therefore, the study of petit-spot basalts potentially provides information about the nature of the asthenosphere as a fundamental theory of plate tectonics. In this study, the analysis of major and trace element compositions, Sr, Nd, and Pb isotopic ratios, and Ar-Ar datings are performed for western Pacific petit-spot volcanoes to investigate the chemical characteristics of upper mantle below the oldest portion of the Pacific Plate. We report the nature of melting source of the petit-spot magmas on the basis of their geochemistry and some modelled compositions of partial melt from carbonated materials.

  31. Mantle compositions below petit-spot volcanoes of the NW Pacific Plate International-presentation

    2017 AGU Fall Meeting　2017/12/10

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    V51D-0375

  32. Accretionary records on Japanese archipelago, NW Pacific rim International-presentation

    The Geological Society of America 129th Annual Meeting　2017/10/22

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    115-6

  33. 三浦層群三崎層火山噴出物中の異質礫の全岩組成及び鉱物組成

    日本地質学会第124年学術大会, 2017年愛媛大会　2017/09/16

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    鈴木陽一, 平野直人

  34. 最古の太平洋プレート上に存在する南鳥島の地質学的意義

    平野直人, 河野尊臣, 森下泰成, 角野浩史

    日本地質学会第124年学術大会, 2017年愛媛大会　2017/09/16

  35. Origin of diagenetic signal in hydrogenetic ferromanganese crusts from petit-spot volcanoes International-presentation

    Keishiro Azami, Naoto Hirano, Naoya Takahashi, Takahiro Watanabe

    AOGS 14th Annual Meeting　2017/08/06

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    SE13-A011

  36. Structure of asthenosphere interpreted by submarine petit-spot volcanoes International-presentation

    Yuki Sato, Naoto Hirano

    AOGS 14th Annual Meeting　2017/08/06

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    SE27-A002

  37. 超深海における海水起源鉄マンガンクラストのREY組成

    浅見慶志朗, 平野直人, 町田嗣樹, 安川和孝, 加藤泰浩

    JpGU-AGU Joint Meeting 2017　2017/05/20

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    MIS17-P01

  38. Direct-ascended petit-spot magma from asthenosphere with little or no assimilation

    佐藤勇輝, 平野直人

    JpGU-AGU Joint Meeting 2017　2017/05/20

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    SCG71-04,受賞発表

  39. Existence of CO2-rich melt in the asthenosphere evidenced by petit-spot International-presentation

    Shiki Machida, Tetsu Kogiso, Naoto Hirano

    JpGU-AGU Joint Meeting 2017　2017/05/20

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    S-CG52-06

  40. Metasomatic records of lithosphere prior to subduction inferred from petit-spot International-presentation

    Naoto Hirano, Yuki Sato, Arashi Taki

    JpGU-AGU Joint Meeting 2017　2017/05/20

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    SCG67-07

  41. Igneous activities of the Paleo-Kuril forearc induced by Izanagi-Pacific ridge International-presentation

    Taku Yutani, Naoto Hirano

    JpGU-AGU Joint Meeting 2017　2017/05/20

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    MIS08-04

  42. 各地の深海底で発見されるプチスポット火山

    平野直人, 佐藤勇輝, 町田嗣樹, 清水健二, 森下泰成, 山本順司, 中西正男, 石井輝秋

    ブルーアース2017, JAMSTEC　2017/03/02

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    BE17-08

  43. 新たに判明した超深海における鉄マンガンクラストのREE組成

    浅見慶志朗, 平野直人, 町田嗣樹, 安川和孝, 加藤泰広

    ブルーアース2017, JAMSTEC　2017/03/02

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    BE17-P54, 受賞発表

  44. 最も古い太平洋プレート上のプチスポット海底火山

    平野直人, 町田嗣樹, 岩野英樹, 角野浩史, 清水健二, 森下泰成, 田村明弘, 坂田周平, 石井輝秋, 檀原徹, 荒井章司, 平田岳史

    日本地球化学会第63回年会　2016/09/14

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    3C10

  45. プチスポット溶岩中の捕獲結晶が持つマントルの情報

    滝嵐, 平野直人, 山本順司

    日本地球化学会第63回年会　2016/09/14

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    3P10

  46. 南鳥島の形成過程とその周辺海丘群の火山活動

    河野尊臣, 平野直人, 森下泰成

    日本地球化学会第63回年会　2016/09/14

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    3P33

  47. 三浦層群三崎層火山噴出物中の異質礫の岩石学的研究

    鈴木陽一, 平野直人

    日本地質学会第123年学術大会　2016/09/10

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    R13-P-1

  48. 古千島弧前弧海盆におけるショナイトの火成活動の時間分布・空間分布

    油谷拓, 平野直人

    日本地質学会第123年学術大会　2016/09/10

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    R2-P-1

  49. REE and Y distribution in deep submarine ferromanganese crusts International-presentation

    Keishiro Azami, Naoto Hirano, Shiki Machida, Kazutaka Yasukawa, Yasuhiro Kato

    Goldschmidt 2016　2016/06/26

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    09c-154

  50. Structure of suboceanic mantle below petit-spot volcanoes International-presentation

    Naoto Hirano

    Japan Geoscience Uninon Meeting 2016　2016/05/22

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    SIT08-07

  51. Temporal and spatial distribution of Cretaceous shoshonites in the Proto-Kuril forearc basin

    Yutani Taku, Hirano Naoto

    Annual Meeting of the Geological Society of Japan　2016

  52. Flexural bending-induced plumelets and their seamounts in accretionary (Japanese-style) and collisional (Tethyan-style) orogenic belts International-presentation

    Naoto Hirano, Yildirim Dilek

    AGU 2015 Fall Meeting　2015/12/14

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    T41E-2955

  53. Alkaline volcanisms in the Proto-Kuril forearc International-presentation

    Taku Yutani, Naoto Hirano

    AGU 2015 Fall Meeting　2015/12/14

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    V51G-3111

  54. 根室層群に貫入するアルカリ玄武岩について

    油谷拓, 平野直人

    日本地質学会第122年学術大会（長野大会）　2015/09/11

  55. Petit-spot lavas as a window into the geochemistry of the asthenospher International-presentation

    Naoto Hirano

    Goldschmidt 2015　2015/08/16

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    Session#17d: Volatiles, redox state, and partial melts in the asthenosphere down to the transition zone

  56. プチスポット溶岩中のかんらん石捕獲結晶

    滝嵐, 平野直人, 山本順司, 町田嗣樹, 石井輝秋

    日本地球惑星科学連合2015年大会　2015/05/24

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    SCG64-P07

  57. 南鳥島の溶岩と形成過程

    河野尊臣, 平野直人, 森下泰成

    日本地球惑星科学連合2015年大会　2015/05/24

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    SCG64-P06

  58. 南鳥島周辺海域のプチスポット

    平野直人, 岩野英樹, 清水健二, 森下泰成, 田村明弘, 角野浩史, 坂田周平, 町田嗣樹, 石井輝秋, 檀原徹, 荒井章司, 平田岳史

    日本地球惑星科学連合2015年大会　2015/05/14

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    SCG64-24

  59. Petit-spot and geology in NW Pacific International-presentation

    Naoto HIRANO, Masao NAKANISHI, Shiki MACHIDA, Junji YAMAMOTO, Teruaki ISHII

    2014 Annual Meeting, Geological Society of America　2014/10/19

  60. 北西太平洋のアウターライズ手前で活動したプチスポット初生マグマの最終平衡温度圧力条件

    町田嗣樹, 小木曽哲, 平野直人

    2014年度日本地球化学会年会　2014/09

  61. プチスポットの配列と海洋プレートの変形構造

    平野直人, 中西正男

    日本地球惑星科学連合2014年大会　2014/04/28

  62. Mantle structure below the petit-spot International-presentation

    Naoto Hirano, Junji Yamamoto, Satoshi Okumura

    Goldschmidt2013　2013/08/25

  63. フレンチポリネシア海域の海底火山探索

    平野直人, 中西正男, 阿部なつ江, 町田嗣樹

    日本地球惑星科学連合2013年大会　2013/05/19

  64. 嶺岡帯の火成岩類とアルコース砂岩の地質年代

    平野直人, 奥澤康一

    日本地質学会関東支部 第1回「房総・三浦地質研究サミット」　2013/03/09

  65. プチスポット海底火山から見た沈み込むプレート直下のマントル同位体組成

    平野直人, 町田嗣樹

    2012年度同位体比部会研究会　2012/11/21

  66. Carbon dioxide of petit-spot submarine volcanoes off Japan and Chile trenches International-presentation

    2012 Annual Meeting, Geological Society of America　2012/11/04

  67. チリ海溝のプチスポット火山

    平野直人, 町田嗣樹, 阿部なつ江, 森下知晃, 田村明弘, 荒井章司

    2012年度 日本地球化学会年会　2012/09

  68. Role of volatiles on petit-spot volcanoes International-presentation

    Naoto Hirano, Satoshi Okumura

    Japan Geoscience Uninon Meeting 2012　2012/05

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    MIS04-04

  69. マグマ分化から探る北西太平洋シャツキー海膨の形成過程： 単斜輝石組成からの制約

    矢崎舞, 平野直人, 佐野貴司

    日本地球惑星科学連合2012年大会　2012/05

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    MIS31-P13

  70. Determination of condition for petit-spot magma generation using multiple saturation experiment

    Machida Shiki, Kogiso Tetsu, Hirano Naoto

    Abstracts of Annual Meeting of the Geochemical Society of Japan　2012

  71. グリーンタフ時代の太平洋側火山活動とプチスポット

    日本地質学会第118年学術大会・日本鉱物科学会2011年年会合同学術大会　2011/09

  72. 南鳥島の形成史、および周辺海域の海洋底調査

    森下泰成, 伊集院勇, 町田怜史

    日本地球惑星科学連合2011年大会　2011/05

  73. Marine geology including igneous rock, Mn- nodule, etc. around the Minami-Torishima Island.

    ISHII Teruaki, HIRANO Naoto

    Annual Meeting of the Geological Society of Japan　2011

  74. The alkaline magma squeezed upward by the plate flexure prior to subduction off the Chile and Japan Trenches International-presentation

    Naoto HIRANO, Shiki MACHIDA, Natsue ABE

    2010 Fall Meeting, American Geophysical Union　2010/12/13

  75. プチスポット火山からの炭素放出量の見積もり

    奥村聡, 平野直人

    2010年日本火山学会秋季大会　2010/10/11

  76. 付加体へ取り込まれるプチスポット火山体

    平野直人

    日本鉱物科学会 2010年年会　2010/09/25

  77. 付加体へ取り込まれるプチスポット火山体

    日本鉱物科学会 2010年年会　2010/09/23

  78. チリ海溝とトンガ海溝沖のプチスポット火山

    平野直人, 町田嗣樹, 阿部なつ江

    2010年度日本地球化学会年会　2010/09/08

  79. チリ海溝とトンガ海溝沖のプチスポット火山

    平野直人, 町田嗣樹, 阿部なつ江

    2010年度日本地球化学会年会　2010/09/07

  80. The 4th volcanic zone, petit-spot, in response to plate flexure International-presentation

    2009 Fall Meeting, American Geophysical Union　2009/12/14

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    V54A-07

  81. 新種の火山・プチスポットの世界的普遍性

    日本地球惑星科学連合2009年大会　2009/05/16

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    C104-009

  82. 沈み込む海洋プレート上の新タイプ火山活動の発見とメカニズムの解明

    日本地球化学会2008年度年会　2008/09/17

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    2J-03

  83. New type of volcano, petit-spot, in response to the plate flexure International-presentation

    2008 IAVCEI General Assembly　2008/08/18

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    Abstracts Orals Thursday p.62 1-g Geodynamic and Tectonic Controls on Volcanism

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Research Projects 11

  1. Exploring petit-spot volcanoes into accretionary complex

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: Tohoku University

    2020/04/01 - 2023/03/31

  2. 北海道東部太平洋側の特異な地質基盤に起因する植生・気候・文化・産業

    Offer Organization: 東京地学協会

    System: 研究・調査助成

    2021/06 - 2022/05

  3. Fluid flow and heat transport processes associated with deformation of the incoming plate near trenches and their influence on subduction zones

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: The University of Tokyo

    2018/04/01 - 2022/03/31

  4. An integrated study of plate interface rocks: Understanding the unread processes and secular changes by in-situ isotope analyses

    Tsujimori Tatsuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2018/04/01 - 2021/03/31

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    Understanding 'plate interface rocks' is of considerable importance. The subduction of crustal material to mantle depths plays a crucial role in the evolution of the continental crust as well as Earth's mantle. Large-scale mass-circulation may have attended plate convergence margins throughout Earth history. This 3-years project has intended to apply texture-based in-situ isotope analytical techniques to the study of 'plate interface rocks'. This study has proven the advantage of in-situ isotope analyses and high-precision stable isotope analyses to characterize some specific metamorphic minerals, such as lawsonite, jadeite, phengite, and serpentine. All the results of this project would manifest that the various isotopic signatures of metamorphic minerals would be an effective tool for investigating convergent margins. This new approach would constrain the geochemical evolution of the convergent margin more quantitatively and it can bring petrotectonic studies to a new level.

  5. Tectonic process resolved by geochemistry of submarine basalts

    Hirano Naoto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: Tohoku University

    2017/04/01 - 2020/03/31

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    Previous researches indicate that most of petit-spot erupted on concavely flexed plate are highly reacted with the depleted lithosphere during the magma ascending to surface. Geochemical composition of entrained xenolith from depleted mantle is disturbed by wall-rock interaction (Pilet et al., 2016). The research cruise KS-18-9, R/V Shinseimaru, in order to access the asthenosphere in August 2018 newly discovered the directly ascending petit-spot melt from asthenosphere (Sato, Hirano et al., 2018). The lavas, silica-poor and strongly alkaline with phenocrystic olivines, are completely discriminated from the majority of previous petit-spots. They selectively erupt atop the outer-rise wherein the lithosphere behaves entirely extensional during the ascent of melt from asthenosphere. Collaborated works with Univ. Bayreuth (Germany), Nanyang Tech. Univ. (Singapore), and Second Instit. Oceanogr. (China) provided several papers of Hirano et al. (2019), and Liu, Hirano et al. (2020).

  6. An integrated study of Paleoproterozoic high-pressure intermediate-type metamorphic belt: Implication for the operation of modern-style subduction processes

    Tsujimori Tatsuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2015/04/01 - 2018/03/31

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    High-pressure intermediate-type metamorphic belt surrounding the late Archean Tanzania Craton experienced Pacific-type subduction zone metamorphism in Orosirian Period at ca. 2 Ga. Epidote-amphibolite-facies meta-pillow basalts of the belt had a mid-ocean ridge basalt-like affinity. Details of eclogite- and high-pressure granulite-facies metamorphism has also brought new insight into Paleoproterozoic Pacific-type subduction processes.

  7. Volcanic activity on subducting Pacific plate with change of the stress field after an earthquake on plate boudary

    HIRANO Naoto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2012/04/01 - 2014/03/31

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    The new kind submarine volcanoes, petit-spot, were erupted on the subducting plate, which occur in a region of the plate-flexure prior to subduction into the trench off NE Japan. Monogenetic petit-spot volcanoes located on the NW Pacific Plate are too tiny, less than 2 km in diameter, and yield eruption ages of various times during 0 to 9 Ma with three new data of Ar-Ar datings of 3.8, 6.2, and 9.2 Ma each (papers in preparation). The erupting time would be over the 0 to 10 Ma along the present plate motion, suggesting the episodic eruption of magma over a large eruption area but with low volumes of magma production. As some samples, however, are generally not used to be analyzed by sample-irradiated ArAr dating, this study adopted the U-Pb dating with the separation of zircons and apatites, awaiting for future dating results. This study is reported by the oral presentation in JpGU 2014 Meeting, and the paper in Geochemical Journal (Hirano et al., 2013).

  8. 新種の火山から放出される二酸化炭素と地球の炭素循環

    Offer Organization: 公益財団法人 東レ科学振興会

    System: 東レ科学技術研究助成

    2012/04 - 2014/03

  9. Exploring petit-spot volcanoes

    HIRANO Naoto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

    Category: Grant-in-Aid for Young Scientists (B)

    Institution: Tohoku University

    2010 - 2011

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    The widespread occurrence of petit-spot volcanoes could be indicated by the discovery of petit-spots at other sites. The research cruises were conducted at the area around the Marcus Island and off the Chile Trench oceanward slope in order to explore the submarine petit-spot volcanoes. Radiometric ages of obtained rock-samples are corresponding to the time on plate-flexure. Petit-spot volcanoes, therefore, could be formed ubiquitously wherever the plate flexes under the influence of plate tectonics.

  10. Multidisciplinary research on petit-spot volcanism. petrology and at sea field survey : implications for the understanding of the development of the oceanic plate

    ABE Natsue, BABA Kiyoshi, ARAI Shoji, FUJIWARA Toshiya, SUGIOKA Hiroko, SUZUKI Katsuhiko, YAMANO Makoto, HIRANO Naoto, NAKANISHI Masao, MICHIBAYASHI Katsuyoshi, ISHIKAWA Masahiro, MACHIDA Shiki, SHITO Azusa, ITO Aki, SENDA Ryoko, MIZUKAMI Tomoyuki, SHIMIZU Kenji, MORISHITA Tomoaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Japan Agency for Marine-Earth Science and Technology

    2008 - 2011

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    Petit-spot is a crap of young(<10 Ma) small volcanoes recently discovered in the NW Pacific Plate with Early Cretaceous age(～ 130), which is plain quiet area and was regarded as tectonically non-active. This project has been taken multidisciplinary survey and study on petitspot and aim to understand the oceanic plate and lithosphere/asthenosphere boundary. The result of this research provides important data to the study on the arc activities because the target area of this research is in the subducting oceanic plate beneath NE Japan arc.

  11. 深海底アルカリ玄武岩に基づくアセノスフェアの解明

    平野 直人

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 東京工業大学

    2004 - 2006

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    本年度は主に、カリフォルニア大学サンディエゴ校・スクリプス海洋研究所において研究を行った。同研究所では、大量に蓄積されている深海底音響データを用い、世界のプレート屈曲場での火山の存在を確認するためのデータ処理を行った。東京工業大学との共同研究では本研究テーマの火山の発生要因を探るため、高温高圧発生装置を用いた深部マントルの再現実験を行った。 7月28日(日本時間)には、本研究の成果がサイエンス誌から発表された(Hirano et al.,2006)。その後国内外、各国の新聞、雑誌、テレビなど各メディアの取材を受け、研究成果は全世界に発信された。本研究の火山が、これまで予測されていなかった成因で生じた新種の火山であること、マグマの起源が未だ解明されていないアセノスフェアの状態を示すものであることなど、本研究の成果によって様々な新しい事実が判明し、このニュースは大変インパクトの大きいものであった。更に1月には、Hirano et al.(2006)の論文の内容を受け、地球科学、特に地球化学で著名なR.Hofmannらのレターを受け、Hiranoらは応答レターを書き、それらは再びサイエンスへ公表された。 本研究の成果発表アクティビティとしては、国内学会は9月に高知で行われた日本地質学会に参加し、口頭発表を行った。海外の学会では、12月にサンフランシスコで行われたAmerican Geophysical Union Fall Meetingにおいてポスター発表を行った。また、9月にポートランド行われたIODP Mission Moho Workshopでは、深海底掘削計画における本研究の火山の意義をアピールし、ポスター発表も行った。そのほかいくつかの依頼講演(4月:東京大学地震研究所,9月:東京大学海洋研究所,スクリプス海洋研究所,10月:海洋研究開発機構)を発表した。

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Works 2

  1. 根室フォトコンテスト 2023・優秀賞【納沙布岬部門】「望郷」

    平野直人

    2024 - Present

    Type: Artistic work

  2. 第15回惑星地球フォトコンテスト・優秀賞「道東太平洋岸の特異な地質と固有のナガコンブ」

    平野直人

    2024 - Present

    Type: Artistic work

Social Activities 8

  1. 清滝小学校依頼授業

    2015/10/01 -

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    地震と火山はどこでおこるの？

  2. 磐城高校スーパーサイエンスハイスクール

    2015/04/23 -

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    大学生活の紹介と学術講演「深海底の調査と地殻変動」

  3. 東北アジア研究センター公開講演会

    2014/12/06 -

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    東北アジアの自然誌 -地球・自然のダイナミクス-「東北アジア地域の地殻変動と太平洋」講演

  4. 海洋と地球の学校

    2014/09/06 -

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    大学・大学院生対象、海洋と地球の学校開催。「新種の火山・プチスポット海底火山と海洋プレート、アセノスフェア」講演。

  5. 清滝小学校６年生依頼授業

    2013/10/03 -

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    地震と火山はどこでおこるの？

  6. 東北大学附置研究所等一般公開「片平まつり2011」記念講演会における一般講演

    2011/10/09 -

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    講演会を開催し、一般市民向け講演「火山はどこで発生するの？～海底火山を掘って考える～」を行った。

  7. 月舘小学校６年生依頼授業

    2010/12/01 -

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    伊達市立月舘小学校・教諭からの依頼に基づいて、火山と地震の発生場や最新の深海底科学に関する９０分間授業を行った。

  8. 新型火山、チリ沖にも 東北大など発見

    2010/10/06 -

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Media Coverage 7

  1. Descubren en la Fosa de Japón el campo hidrotermal más profundo del mundo

    El Dias

    2023/07

  2. Petit-spot volcanoes are the deepest known submarine hydrothermal activity

    https://www.terradaily.com/reports/Petit_spot_volcanoes_involve_the_deepest_known_submarine_hydrothermal_activity_possibly_release_CO2_and_methane_999.html

    2023/07

    Type: Internet

  3. Pequenos vulcões submarinos podem influenciar ciclo do carbono na Terra

    Canaltech　Canaltech　https://canaltech.com.br/meio-ambiente/pequenos-vulcoes-submarinos-podem-influenciar-ciclo-do-carbono-na-terra-251558/

    2023/07

    Type: Internet

  4. Petit-spot volcanoes involve the deepest known submarine hydrothermal

    ScienMag　https://scienmag.com/petit-spot-volcanoes-involve-the-deepest-known-submarine-hydrothermal-activity-possibly-release-co2-and-methane/

    2023/07

    Type: Internet

  5. Unveiling the Deepest Hydrothermal Activity

    todayheadline.co　Today Headline　https://todayheadline.co/unveiling-the-deepest-hydrothermal-activity/

    2023/07

    Type: Internet

  6. Petit-spot volcanoes involve deepest known submarine hydrothermal activity, may release methane

    Science X Network　Phys.org

    2023/07/01

    Type: Internet

  7. Small Volcanoes Play Big Role in Clarifying Tectonic Plate Structures

    https://www.miragenews.com/small-volcanoes-play-big-role-in-clarifying-779771/

    2022/05/11

    Type: Internet

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Academic Activities 6

  1. 東京大学地震研究所共同利用研究集会 「海溝海側の変動現象と沈み込み帯へのインプット」

    2023/11/26 - 2023/11/27

    Activity type: Competition, symposium, etc.

  2. 地球惑星科学連合2023年大会「沈み込み帯へのインプット：海洋プレートの進化と不均質」S-CG63

    2023/05/24 - 2023/05/24

    Activity type: Academic society, research group, etc.

  3. 日本地球化学会第69回年会セッション 「太平洋プレートの変遷史 (S02)」コンビナー

    2022/04/01 - 2022/09/07

    Activity type: Academic society, research group, etc.

  4. Island Arc特集号"Orogens, Ophiolites and Oceans: A Snapshot of Earth's Tectonic Evolution"編集委員

    2021/04/01 - 2022/08/31

    Activity type: Peer review

  5. 日本地球化学会 第71回年会 「太平洋プレートの変遷史～深海底からマントルへ (S03)」

    2024/09/18 -

    Activity type: Academic society, research group, etc.

  6. 地球惑星科学連合2024年大会「沈み込み帯へのインプット：海洋プレートの進化と不均質」S-CG52

    2024/05/27 -

    Activity type: Academic society, research group, etc.

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Other 14

  1. プチスポット火山のMg同位体組成

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    Mg同位体分析の変動からマントル起源の状態を解明する

  2. アセノスフェアの三価鉄および炭素組成

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    プチスポットマグマの炭素組成および三価鉄組成の実験、分析により、アセノスフェアの化学組成を決定する。

  3. Goldschmidt Conference 「Petit-spot lavas as a window into the geochemistry of the asthenosphere」 講演

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    Goldschmidt Conferenceに参加し講演を行うための渡航

  4. 付加体中のアルカリ岩の成因

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    北海道東部およびカリフォルニアに産する付加体中のアルカリ玄武岩類の成因論

  5. 根室～歯舞群島マグマの成因解明と新型マグマの検証

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    根室～歯舞群島マグマの成因解明と新型マグマの検証

  6. 海洋と地球の学校－大学生・大学院生のための地学研究普及活動

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    海洋研究を主軸に、地球科学を学ぶ全国の大学、大学院生対象に行う勉強会・巡検の開催

  7. 海洋プレート構造と小規模火山活動

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    プレート構造やプレート屈曲に起因する火山活動の時空変遷

  8. 前弧火成活動の成因解明

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    前弧域で活動するアルカリマグマの成因解明

  9. Mantle volatiles on submarine quenched lavas

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    マグマ中の揮発成分や微量元素を見積もり、マントル組成を決定する

  10. マグマの複数相飽和実験

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    プチスポットマグマの成因解明

  11. 新種の火山から放出される二酸化炭素と地球の炭素循環

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    プチスポット火山のマグマ中の二酸化炭素濃度を見積もり、水と二酸化炭素の脱ガス過程を考慮し、マグマ発生時の二酸化炭素含有量を見積もる。また、マグマの起源物質や溶融度を考慮し、マントル中の二酸化炭素含有量を決定する。

  12. 西太平洋海山・海洋島の形成史

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    太平洋プレート上の西部海山群の形成史を明らかにする

  13. The 4th volcanic zone, petit-spot, in response to plate flexure

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    サンフランシスコ開催の2009 AGU (American Geophysical Union) Fall Meetingにおける「The 4th volcanic zone, petit-spot, in response to plate flexure」講演

  14. 太平洋プレート上の白亜紀海山海台の関連する地球規模の火山活動の解明、および、その火山活動と地球規模の環境変動との関連

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    北西太平洋に分布する白亜紀の海山海台の研究を行う。これらは、白亜紀の全地球規模の火成活動（白亜紀中期のスーパープルームエピソード；Larson, 1992）の産物であると言われており、地球史上まれに見る規模の白亜紀の環境変動との関連も重要視されている。また、当時形成された海山や海台の年代から、当時の太平洋プレート移動方向、移動速度の情報が得られることが期待され、北西太平洋の海山や海台から得られた岩石試料にAr-Ar年代を与えることにより、古太平洋プレートの運動、またその運動が周囲に及ぼす影響として、環太平洋における白亜紀付加帯の起源が解明されていく可能性がある。

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