Updated on 2024/06/22

写真a

 
TAKAZAWA Eiichi
 
Organization
Academic Assembly Institute of Science and Technology CHIKYU SEIBUTSU KAGAKU KEIRETU Professor
Faculty of Science Professor
Graduate School of Science and Technology Environmental Science and Technology Professor
Title
Professor
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Degree

  • Ph.D. ( 1996.9   Massachusetts Institute of Technology )

Research Interests

  • マントル岩石学

Research Areas

  • Natural Science / Solid earth sciences

Research History (researchmap)

  • Japan Agency for Marine-Earth Science and Technology   Guest Researcher

    2021.4 - 2024.3

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  • Japan Agency for Marine-Earth Science and Technology   Visiting Principal Researcher

    2014.4 - 2021.3

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  • Niigata University   Faculty of Science   Professor

    2013.5

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    Country:Japan

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  • Niigata University   Graduate School of Science and Technology   Professor

    2013.5

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    Country:Japan

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  • Niigata University   Faculty of Science   Associate Professor

    2004.4 - 2013.4

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    Country:Japan

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  • Niigata University   Faculty of Science   Associate Professor (as old post name)

    1999.10 - 2004.3

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    Country:Japan

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  • Niigata University   Faculty of Science   Lecturer

    1997.10 - 1999.9

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    Country:Japan

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Research History

  • Niigata University   Professor

    2013.5

  • Niigata University   Graduate School of Science and Technology Environmental Science and Technology   Professor

    2013.5

  • Niigata University   Graduate School of Science and Technology Environmental Science and Technology   Professor

    2013.5

  • Niigata University   Faculty of Science Department of Geology   Professor

    2013.5 - 2017.3

  • Niigata University   Faculty of Science Department of Geology   Associate Professor

    2004.4 - 2013.4

  • Niigata University   Faculty of Science   Lecturer

    1997.1 - 1999.9

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Education

  • Massachusetts Institute of Technology   Department of Earth, Atmospheric and Planetary Sciences

    1990.9 - 1996.6

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    Country: United States

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  • Kumamoto University   Graduate School of Science and Technology   環境科学専攻

    1989.4 - 1995.3

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    Country: Japan

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  • Hokkaido University   大学院理学研究科   地質学鉱物学専攻

    1987.4 - 1989.3

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    Country: Japan

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  • Hokkaido University   School of Science   地質学鉱物学科

    1982.4 - 1986.3

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    Country: Japan

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Papers

  • Genesis of Rare Metal Granites in the Nubian Shield: Tectonic Control and Magmatic and Metasomatic Processes

    Mohamed Zaki Khedr, Saif M. Abo Khashaba, Eiichi Takazawa, Safaa M. Hassan, Mokhles K. Azer, N. H. El-Shibiny, Kamal Abdelrahman, Yuji Ichiyama

    Minerals   2024.5

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/min14050522

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  • The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

    Prof. Mohamed Khedr, Gehad M. Saleh, Abdelfadil, K. M., Eiichi Takazawa, kamal Hassanein, Akihiro Tamura, Shaimaa Ali El-Shafei

    Minerals   2024.4

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/min14050465

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  • The magnesium isotopic composition of the mantle

    Xiao-Ning Liu, Remco C. Hin, Christopher D. Coath, Michael Bizimis, Li Su, Dmitri A. Ionov, Eiichi Takazawa, Richard Brooker, Tim Elliott

    Geochimica et Cosmochimica Acta   2023.10

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.gca.2023.08.011

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  • Remote sensing and geochemical investigations of sulfide-bearing metavolcanic and gabbroic rocks (Egypt): Constraints on host-rock petrogenesis and sulfide genesis

    Mohamed Zaki Khedr, Samir Kamh, Ahmed A. Al Desouky, Eiichi Takazawa, Christoph Hauzenberger, Scott A. Whattam, Amr El-Awady

    Gondwana Research   2023.7

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.gr.2023.03.021

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  • Integration of remote sensing and geochemical data to characterize mineralized A-type granites, Egypt: implications for origin and concentration of rare metals

    Mohamed Zaki Khedr, Saif M. Abo Khashaba, N. H. El-Shibiny, Eiichi Takazawa, Safaa M. Hassan, Mokhles K. Azer, Scott A. Whattam, Reda A. El-Arafy, Yuji Ichiyama

    International Journal of Earth Sciences   2023.6

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s00531-023-02323-4

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    Other Link: https://link.springer.com/article/10.1007/s00531-023-02323-4/fulltext.html

  • Application of remote sensing data integration in detecting mineralized granitic zones: A case study of the Gabal Al-Ijlah Al-Hamra, Central Eastern Desert, Egypt

    Saif M. Abo Khashaba, N.H. El-Shibiny, Safaa M. Hassan, Eiichi Takazawa, Mohamed Zaki Khedr

    Journal of African Earth Sciences   200   104855 - 104855   2023.4

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jafrearsci.2023.104855

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  • Genesis and evaluation of heavy minerals in black sands: A case study from the southern Eastern Desert of Egypt Reviewed

    Mohamed Zaki Khedr, Hamada Zaghloul, Eiichi Takazawa, Hesham El-Nahas, Mokhles K. Azer, Shaimaa Ali El-Shafei

    Geochemistry   83 ( 1 )   125945 - 125945   2023.4

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.chemer.2022.125945

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  • Preface: Special Issue on Ophiolites and Oceanic Lithosphere

    Peter B. Kelemen, Jürg M. Matter, Damon A.H. Teagle, Jude A. Coggon, Marguerite Godard, Katsuyoshi Michibayashi, Eiichi Takazawa, Alexis S. Templeton, Ken Williams, Zaher Al Sulaimani

    Journal of Geophysical Research: Solid Earth   128 ( 4 )   2023.4

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    With this Preface, we provide background information, a scientific overview of topics, and an annotated bibliography of the 63 papers published in the Journal of Geophysical Research (JGR) Special Issue on “Ophiolites and Oceanic Lithosphere, with a Focus on the Samail Ophiolite,” collected online at https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)2169-9356.SAMAIL1. Topics covered in the Special Issue include formation and alteration of igneous ocean crust at submarine spreading centers, subduction zone mass transfer at the leading edge of the mantle wedge, the tectonic emplacement and evolution of ophiolites, processes of alteration and weathering of tectonically exhumed mantle peridotite, and the subsurface biosphere in the peridotite weathering environment. The bibliography, in the form of a supplementary Excel spreadsheet with links to each paper, is organized by topic, but can be sorted by first author, order of publication, specific Oman Drilling Project boreholes, and other factors.

    DOI: 10.1029/2023JB026677

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  • The cadmium and zinc isotope compositions of the silicate Earth – Implications for terrestrial volatile accretion Reviewed

    Harvey Pickard, Emeliana Palk, Maria Schönbächler, Rebekah E.T. Moore, Barry J. Coles, Katharina Kreissig, Katrina Nilsson-Kerr, Samantha J. Hammond, Eiichi Takazawa, Christophe Hémond, Peter Tropper, Dan N. Barfod, Mark Rehkämper

    Geochimica et Cosmochimica Acta   338   165 - 180   2022.12

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.gca.2022.09.041

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  • Remote sensing techniques and geochemical constraints on the formation of the Wadi El-Hima mineralized granites, Egypt: new insights into the genesis and accumulation of garnets Reviewed

    Mohamed Zaki Khedr, Saif M. Abo Khashaba, N. H. El-Shibiny, Reda A. El-Arafy, Eiichi Takazawa, Mokhles K. Azer, Richard. M. Palin

    International Journal of Earth Sciences   111 ( 7 )   2409 - 2443   2022.10

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    The Wadi El-Hima Neoproterozoic I- and A-type granites in the Southern Eastern Desert of Egypt are rich in garnets (up to 30 vol%) and are cut by NW–SE strike-slip faults, as confirmed from structure lineament extraction maps. These mineralized granites and garnet mineralization zones can be successfully discriminated using remote sensing techniques. Spectral angle mapper and matched filtering techniques are highly effective for mapping garnet-rich zones and show that the highest garnet concentrations occur along the intrusive contact zone of NW–SE striking faults. El-Hima granites have high SiO<sub>2</sub> (73.5–75.1 wt%), Al<sub>2</sub>O<sub>3</sub> (13.4–15.3 wt%) and total alkali (6.7–8.7 wt%) contents, suggesting that they were sourced from peraluminous (A/CNK &gt; 1) parental magmas. Garnet-bearing trondhjemites are metasomatic in origin and formed after I-type tonalite-granodiorites, which originated in a volcanic arc tectonic setting. Garnet-rich syenogranites and alkali-feldspar granites are both post-collisional A-type granites: the syenogranites formed from peraluminous magmas generated by partial melting of lower crustal tonalite and metasedimentary protoliths during lithospheric delamination, and the alkali-feldspar granites crystallized from highly fractionated, felsic and alkali-rich peraluminous magmas in the upper crust. Garnets in El-Hima mineralized granites occur in three forms: (1) subhedral disseminated crystals, (2) vein-type crystals, and (3) aggregated subhedral crystals, reflecting different mechanisms of accumulation. All are dominantly almandine in composition (Alm<sub>76</sub>Sps<sub>10</sub> Prp<sub>7</sub>Grs<sub>6</sub>Adr<sub>1</sub>) and have high average concentrations of heavy rare earth elements (HREE) (ΣHREE = 1636 ppm), Y = (3394 ppm), Zn (325 ppm), Li (39.17 ppm) and Ga (34.94 ppm). Garnet REE patterns show strong negative Eu anomalies with HREE enriched relative to LREE, indicating a magmatic origin. These magmatic garnets are late-stage crystallization products of Al-rich hydrous magmas, and formed at low temperature (680–730 °C) and pressure (2.1–2.93 kbar) conditions in the upper continental crust. Peculiar garnet concentrations in syenogranites near and along contact zones with alkali feldspar granites are related to peraluminous parent hydrous magma compositions. These garnets formed by in situ crystallization from A-type granite melts, alongside accumulation of residual garnets left behind after partial melting of the host garnet-rich granites along the intrusive contact. Magmatic-fluid flow along the NW–SE striking fault of Najd system enhanced garnet accumulation in melts, which formed clots and veins of garnet.

    DOI: 10.1007/s00531-022-02237-7

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    Other Link: https://link.springer.com/article/10.1007/s00531-022-02237-7/fulltext.html

  • Styles of Fe–Ti–V ore deposits in the Neoproterozoic layered mafic-ultramafic intrusions, south Eastern Desert of Egypt: Evidence for fractional crystallization of V-rich melts Reviewed

    Mohamed Zaki Khedr, Eiichi Takazawa, Shoji Arai, Robert J. Stern, Tomoaki Morishita, Amr El-Awady

    Journal of African Earth Sciences   194   104620 - 104620   2022.10

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jafrearsci.2022.104620

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  • The nature of the Moho beneath fast‐spreading centers: Evidence from the Pacific plate and Oman ophiolite Reviewed

    Yoshihiko Tamura, Mathieu Rospabé, Gou Fujie, Akane Ohira, Kentaro Kaneda, Alexander R. L. Nichols, Georges Ceuleneer, Tomoki Sato, Shuichi Kodaira, Seiichi Miura, Eiichi Takazawa

    Island Arc   31 ( 1 )   2022.9

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1111/iar.12460

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1111/iar.12460

  • Titanium isotope heterogeneity in the Earth’s mantle: A case study of the Horoman peridotite massif Reviewed

    Merislava Anguelova, Manuela A. Fehr, Eiichi Takazawa, Maria Schönbächler

    Geochimica et Cosmochimica Acta   2022.7

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.gca.2022.07.005

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  • The magnesium isotopic compositions of the crust and mantle: A study on the Oman ophiolite Reviewed

    Jiwon Eom, Toshihiro Yoshimura, Norikatsu Akizawa, Shigeyuki Wakaki, Tsuyoshi Ishikawa, Eiichi Takazawa, Kyoko Yamaoka, Hodaka Kawahata

    Chemical Geology   120969 - 120969   2022.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.chemgeo.2022.120969

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  • Petrogenesis of arc-related serpentinized peridotites (Egypt): Insights into Neoproterozoic mantle evolution beneath the Arabian-Nubian Shield Reviewed

    Mohamed Zaki Khedr, Eiichi Takazawa, Christoph Hauzenberger, Akihiro Tamura, Shoji Arai, Robert James Stern, Tomoaki Morishita, Amr El-Awady

    Journal of Asian Earth Sciences   226   105078 - 105078   2022.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jseaes.2022.105078

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  • Geochemical characterization of the Oman Crust‐Mantle transition zone, OmanDP Holes CM1A and CM2B Reviewed

    F. Kourim, M. Rospabé, N. Dygert, S. Chatterjee, E. Takazawa, K‐L. Wang, M. Godard, M. Benoit, M. Giampouras, K. Ishii, D. A‐H Teagle, M‐J. Cooper, P. Kelemen

    Journal of Geophysical Research: Solid Earth   2022.3

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    Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    DOI: 10.1029/2021jb022694

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  • Ship-board determination of whole-rock (ultra-)trace element concentrations by laser ablation-inductively coupled plasma mass spectrometry analysis of pressed powder pellets aboard the D/V Chikyu Reviewed

    Mathieu Rospabé, Fatma Kourim, Akihiro Tamura, Eiichi Takazawa, Manolis Giampouras, Sayantani Chatterjee, Keisuke Ishii, Matthew J. Cooper, Marguerite Godard, Elliot Carter, Natsue Abe, Kyaw Moe, Damon A. H. Teagle

    Scientific Drilling   30   75 - 99   2022.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Copernicus GmbH  

    Abstract. The Oman Drilling Project (OmanDP), performed under theInternational Continental Scientific Drilling Program (ICDP), is aninternational scientific research project that undertook drilling at a range of sites in the Semail ophiolite (Oman) to collect core samples spanning the stratigraphy of the ophiolite, from the upper oceanic crust down to the basal thrust. The cores were logged to International Ocean Discovery Program (IODP) standards aboard the D/V Chikyu. During ChikyuOman2018 Leg 3 (July–August 2018), participants described cores from the crust–mantle transition (CM) sites. The main rock types recovered at these sites weregabbros, dunites and harzburgites, rocks typically forming the base of theoceanic crust and the shallow mantle beneath present-day spreading centres.In addition to the core description, selected samples were analysed by X-ray fluorescence spectrometry (XRF) for their chemical compositions, including major, minor and some trace elements. To complement these standard procedures, we developed newapproaches to measure ultra-trace element concentrations using a procedureadapted from previous works to prepare fine-grained pressed powder pelletscoupled with laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis using instrumentation aboard the D/V Chikyu. First, three (ultra)mafic reference materials were investigated to test and validate our procedure (BHVO-2, BIR-1a and JP-1), and then the procedure was applied to a selection of gabbro and dunite samples from the CM cores toexplore the limitations of the method in its current stage of development.The obtained results are in good agreement with preferred values for thereference materials and with subsequent solution replicate analyses of the same samples performed in shore-based laboratories following Leg 3 for theCM samples. We describe this procedure for the determination of 37 minor and (ultra-)trace elements (transition elements and Ga, Li and Large-Ion Lithophile Elements (LILE), Rare Earth Elements (REE), High-Field-Strength Elements (HFSE), U, Th, and Pb) in mafic and ultramafic rocks. The presented method has the major advantage that it allows the determination at sea of the(ultra-)trace element concentrations in a “dry”, safe way, without usingacid reagents. Our new approach could be extended for other elements ofinterest and/or be improved to be adapted to other rock materials duringfuture ocean drilling operations aboard the D/V Chikyu and other platforms.

    DOI: 10.5194/sd-30-75-2022

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  • Listvenite Formation During Mass Transfer into the Leading Edge of the Mantle Wedge: Initial Results from Oman Drilling Project Hole BT1B Reviewed

    Peter B. Kelemen, Juan Carlos de Obeso, James A. Leong, Marguerite Godard, Keishi Okazaki, Alissa J. Kotowski, Craig E. Manning, Eric T. Ellison, Manuel D. Menzel, Janos L. Urai, Greg Hirth, Matthew Rioux, Daniel F. Stockli, Romain Lafay, Andreas M. Beinlich, Jude A. Coggon, Nehal H. Warsi, Jürg M. Matter, Damon A. H. Teagle, Michelle Harris, Katsuyoshi Michibayashi, Eiichi Takazawa, Zaher Al Sulaimani

    Journal of Geophysical Research: Solid Earth   127 ( 2 )   2022.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    DOI: 10.1029/2021jb022352

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2021JB022352

  • Deep Sourced Fluids for Peridotite Carbonation in the Shallow Mantle Wedge of a Fossil Subduction Zone: Sr and C Isotope Profiles of OmanDP Hole BT1B

    de Obeso, J.C., Kelemen, P.B., Leong, J.M., Menzel, M.D., Manning, C.E., Godard, M., Cai, Y., Bolge, L., Matter, J., Teagle, D., Coggon, J., Harris, M., Bennett, E., Bompard, N., Boulanger, M., France, L., Früh-Green, G., Garbe-Schönberg, D., Ildefonse, B., Jesus, A., Koepke, J., Koornneef, L., Lafay, R., Lissenberg, J., MacLeod, C., Mock, D., Morris, T., Müller, S., Noël, J., Nothaft, D., Perez, A., Pezard, P., Warsi, N., Zeko, D., Zihlmann, B., Bechkit, M., Brun, L., Célérier, B., Henry, G., Paris, J., Lods, G., Robert, P., Al Amri, S., Al Shukaili, M., Al Qassabi, A., Moe, K., Yamada, Y., Takazawa, E., Michibayashi, K., Abe, N., Akitou, T., AlShahri, S.A., Hamed Shames Al-Siyabi, H., Alhumaimi, S.M., AlRawahi, M.H., Al Sarmi, M.S., Alwaeli, B.H., Beinlich, A., Carter, E., Cheadle, M., Cloos, M., Cooper, M., Crispini, L., Deamer, L., Deans, J., Faak, K., Greenberger, R., Harigane, Y., Hatakeyama, K., Horst, A., Hoshide, T., Ishii, K., Johnson, K., Kettermann, M., Kim, H., Kondo, K., Kotowski, A., Kourim, F., Kusano, Y., Menzies, C., Morishita, T., Nguyen, D.K., Nozaka, T., Okazaki, K., Picazo, S., Senda, R., Tateishi, Y., Till, J., Umino, S., Urai, J., Usui, Y., D’Andres, J.

    Journal of Geophysical Research: Solid Earth   127 ( 1 )   2022

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    Completely carbonated peridotites represent a window to study reactions of carbon-rich fluids with mantle rocks. Here, we present details on the carbonation history of listvenites close to the basal thrust in the Samail ophiolite. We use samples from Oman Drilling Project Hole BT1B, which provides a continuous record of lithologic transitions, as well as outcrop samples from listvenites, metasediments, and metamafics below the basal thrust of the ophiolite. 87Sr/86Sr of listvenites and serpentinites, ranging from 0.7090 to 0.7145, are significantly more radiogenic than mantle values, Cretaceous seawater, and other peridotite hosted carbonates in Oman. The Hawasina sediments that underlie the ophiolite, on the other hand, show higher 87Sr/86Sr values of up to 0.7241. δ13C values of total carbon in the listvenites and serpentinites range from −10.6‰ to 1.92‰. We also identified a small organic carbon component with δ13C as low as −27‰. Based on these results, we propose that during subduction at temperatures above >400°C, carbon-rich fluids derived from decarbonation of the underlying sediments migrated updip and generated the radiogenic 87Sr/86Sr signature and the fractionated δ13C values of the serpentinites and listvenites in core BT1B.

    DOI: 10.1029/2021JB022704

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  • Initial Results From the Oman Drilling Project Multi‐Borehole Observatory: Petrogenesis and Ongoing Alteration of Mantle Peridotite in the Weathering Horizon Reviewed

    Peter B. Kelemen, James A. Leong, Juan Carlos de Obeso, Jürg M. Matter, Eric T. Ellison, Alexis Templeton, Daniel B. Nothaft, Alireza Eslami, Katy Evans, Marguerite Godard, Benjamin Malvoisin, Jude A. Coggon, Nehal H. Warsi, Philippe Pézard, Saebyul Choe, Damon A. H. Teagle, Katsuyoshi Michibayashi, Eiichi Takazawa, Zaher Al Sulaimani

    Journal of Geophysical Research: Solid Earth   126 ( 12 )   2021.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    DOI: 10.1029/2021jb022729

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2021JB022729

  • Operating outdated EPMA (JXA-8600SX) by popular microcomputers and Windows PC Reviewed

    Hayato Ueda, Eiichi Takazawa

    The Journal of the Geological Society of Japan   127 ( 11 )   681 - 686   2021.11

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:The Geological Society of Japan  

    DOI: 10.5575/geosoc.2021.0028

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  • Achievements and Future Prospects of the ICDP Oman Drilling Project Invited Reviewed

    Eiichi TAKAZAWA

    Journal of Geography (Chigaku Zasshi)   130 ( 4 )   507 - 525   2021.8

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    Authorship:Lead author, Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Tokyo Geographical Society  

    DOI: 10.5026/jgeography.130.507

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  • Orthopyroxene–magnetite symplectite in olivine gabbros from the lower crustal Oman Ophiolite: Oman Drilling Project, Hole GT2A Reviewed

    Sayantani CHATTERJEE, Debaditya BANDYOPADHYAY, Eiichi TAKAZAWA, Katsuyoshi MICHIBAYASHI

    Journal of Mineralogical and Petrological Sciences   116 ( 3 )   170 - 175   2021.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Japan Association of Mineralogical Sciences  

    DOI: 10.2465/jmps.201130f

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  • Trace and rare earth element geochemistry of clinopyroxene in mafic dykes from Western Dharwar craton, southern India

    Sasidharan A. SILPA, M. SATISH–KUMAR, Eiichi TAKAZAWA, Krishnan SAJEEV

    Journal of Mineralogical and Petrological Sciences   116 ( 2 )   108 - 112   2021

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    Publishing type:Research paper (scientific journal)   Publisher:Japan Association of Mineralogical Sciences  

    DOI: 10.2465/jmps.201130c

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  • High resolution X–ray computed tomography and scanning electron microscopy studies of multiphase solid inclusions in Oman podiform chromitite: implications for post–entrapment modification Reviewed

    Yuan YAO, Eiichi TAKAZAWA, Sayantani CHATTERJEE, Antonin RICHARD, Christophe MORLOT, Laura CR{\'{E } }ON, Salim AL{\textendash}BUSAIDI, Katsuyoshi MICHIBAYASHI

    Journal of Mineralogical and Petrological Sciences   115 ( 3 )   247 - 260   2020.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Japan Association of Mineralogical Sciences  

    DOI: 10.2465/jmps.191008

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  • The non-chondritic Ni isotope composition of Earth's mantle Reviewed

    Martijn Klaver, Dmitri A. Ionov, Eiichi Takazawa, Tim Elliott

    GEOCHIMICA ET COSMOCHIMICA ACTA   268   405 - 421   2020.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    Nickel is a major element in the Earth. Due to its siderophile nature, 93% of Ni is hosted in the core and the Ni isotope composition of the bulk silicate Earth might inform on the conditions of terrestrial core formation. Whether Earth's mantle is fractionated relative to the chondritic reservoir, and by inference to the core, is a matter of debate that largely arises from the uncertain Ni isotope composition of the mantle. We address this issue through high-precision Ni isotope measurements of fertile- to melt-depleted peridotites and compare these data to chondritic meteorites. Terrestrial peridotites that are free from metasomatic overprint display a limited range in delta Ni-60/58 (deviation of Ni-60/Ni-58 relative to NIST SRM 986) and no systematic variation with degree of melt depletion. The latter is consistent with olivine and orthopyroxene buffering the Ni budget and isotope composition of the refractory peridotites. As such, the average Ni isotope composition of these peridotites (delta Ni-60/58 = 0.115 +/- 0.011 parts per thousand) provides a robust estimate of the delta Ni-60(/)58 of the bulk silicate Earth. Peridotites with evidence for melt metasomatism range to heavier Ni isotope compositions where the introduction of clinopyroxene appears to drive an increase in delta Ni-60(/)58. This requires a process where melts do not reach isotopic equilibrium with buffering olivine and orthopyroxene, but its exact nature remains obscure. Chondritic meteorites have variability in delta Ni-60(/)58 due to heterogeneity at the sampling scale. In particular, CD chondrites are displaced to isotopically lighter values due to sorption of Ni onto ferrihydrite during parent body alteration. Chondrites less extensively altered than the CII chondrites show no systematic differences in delta Ni-60(/)58 between classes and yield average delta Ni-60(/)58 = 0.212 +/- 0.013 parts per thousand, which is isotopically heavier than our estimate of the bulk silicate Earth. The notable isotopic difference between the bulk silicate Earth and chondrites likely results from the segregation of the terrestrial core. Our observations potentially provide a novel constraint on the conditions of terrestrial core formation but requires further experimental calibration. (C) 2019 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.gca.2019.10.017

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  • Scientific Drilling Across the Shoreline Reviewed

    Sean Gulick, Kenneth Miller, Peter Keleman, Joanna Morgan, Jean-Noel Proust, Eiichi Takazawa

    Oceanography   32 ( 1 )   157 - 159   2019.3

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    DOI: 10.5670/oceanog.2019.139

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  • In situ carbon mineralization in ultramafic rocks: Natural processes and possible engineered methods Reviewed

    P.B. Kelemen, R. Aines, E. Bennett, S.M. Benson, E. Carter, J.A. Coggon, J.C. de Obeso, O. Evans, G. Gadikota, G.M. Dipple, M. Godard, M. Harris, J.A. Higgins, K.T.M. Johnson, F. Kourim, R. Lafay, S. Lambart, C.E. Manning, J.M. Matter, K. Michibayashi, T. Morishita, J. Noël, K. Okazaki, P. Renforth, B. Robinson, H. Savage, R. Skarbek, M.W. Spiegelman, E. Takazawa, D. Teagle, J.L. Urai, J. Wilcox

    Energy Procedia   146   92 - 102   2018.7

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    DOI: 10.1016/j.egypro.2018.07.013

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  • Tectonic affinities of the accreted basalts in southern Taiwan Reviewed

    Hsin-Yu Chen, Huai-Jen Yang, Yung-Hsin Liu, Kuo-Fang Huang, Eiichi Takazawa

    JOURNAL OF ASIAN EARTH SCIENCES   158   253 - 265   2018.6

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    Tectonic affinities of accreted basalts provide constraints on mass transport in convergent boundaries, improving our understandings on the evolution of regional geology. In this study, nineteen accreted basalts from the southernmost tip of Taiwan Island, which is on the convergent boundary between the Eurasian and Philippine Sea Plates, were analyzed for element concentrations as well as Sr, Nd, Hf, and Pb isotope ratios to investigate their tectonic affinities. All the samples contain > 3% LOI, reflecting post-magmatic alteration. LOI and Nb variation diagrams together with comparisons to oceanic basalt compositions indicated that the concentrations of most major elements and Rb, Sr, and Ba were modified by post-magmatic processes to varying extents, while P2O5, REE and HFSE remained immobile. Although some samples show Pb loss, most samples have Pb concentrations not affected by post-magmatic processes. Isotope ratios of Pb, Nd and Hf, generally reflect the mantle source characteristics. The epsilon(Nd)-epsilon(Hf) relationship and trace element abundance ratios indicated that the LREE-depleted samples were mostly scraped off the subducting South China Sea floor, reflecting the volumetric dominance of N-MORB on ocean floors. The overriding Philippine Sea Plate contributed both N-MORB and E-MORB to the accretionary prism. The tectonic affinities of the LREE-enriched samples, however, could not be unambiguously determined for the large geochemical variability of OIB from both subducting and overlying slabs. Based on our results, it is proposed that the tectonic affinity of the basalts in an accretionary prism can indicate the subduction polarity of the associated convergent boundary, providing a constraint for regional geology evolution.

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  • Evaluation of time-resolved mean-of-ratios reduction for laser ablation zircon U-Pb dating using quadrupole ICPMS Reviewed

    Hayato Ueda, Eiichi Takazawa, Rinpei Kato, Yoshiko Adachi

    GEOCHEMICAL JOURNAL   52 ( 3 )   241 - 254   2018

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    We examined quality of zircon U-Pb dating results by mean-of-ratios (MOR) reduction of time-resolved analysis acquired with quadrupole inductively coupled plasma mass spectrometer (ICPMS) and 213 nm YAG laser ablation system. Time-resolved MOR reduction has an advantage to enable statistic evaluation of stability of isotopic ratios and detect accidents in each measurement. We practically applied internal mean square weighted deviation (iMSWD) and correlation coefficient of linear regression to dating of five reference zircons. The MOR reduction provided reasonably accurate U-Pb ages with 2-3% errors of precision. However, their iMSWD suggested dispersion of isotopic ratios in excess of counting errors. The dispersion is inferably attributed to non-simultaneous measurements by quadrupole ICPMS, in addition to potential heterogeneity of samples. We also tested quality of age results from manually trimmed time profiles. The test suggested that ages from clipped profiles as short as 5 sec. are still useful if reduction of precision is acceptable. The method enables to extract meaningful ages from measurements containing accidents, when statistically stable parts out of accidents are properly clipped from the time profiles.

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  • Reductive Heating Experiments on BOF-Slag: Simultaneous Phosphorus Re-Distribution and Volume Stabilization for Recycling Reviewed

    Tung-Hsin Su, Huai-Jen Yang, Yu-Chen Lee, Yen-Hong Shau, Eiichi Takazawa, Ming-Fong Lin, Jin-Luh Mou, Wei-Teh Jiang

    STEEL RESEARCH INTERNATIONAL   87 ( 11 )   1511 - 1526   2016.11

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    Basic-oxygen furnace (BOF) slag is the second abundant by-product from the steel-making process. It is not readily recycled for high phosphorus content and volume instability. To eliminate its phosphorus-hosting dicalcium silicate (C2S) and volumetrically unstable free-lime, reductive heating experiments on BOF-slag are carried out at 1300-1600 degrees C using quartz-sand or serpentine as a basicity modifier. In the products, C2S and free-lime are consumed through reacting with CaO and MgO, which are produced by Ca-ferrite and Mg-wustite reduction, respectively, to formmerwinite and akermanite. The products are also characterized by silicatemetal segregation and the extent of that increases with increasing temperature and decreasing particle size of starting mixtures. Thermodynamic calculations show that phosphorus in C2S is mostly converted to Fe2P in the metal domain. Compared to the slag-serpentine experiments, the slag-quartz experiments resulted in higher extents of silicate-metal segregation with lower phosphorus contents of approximate to 0.1% in the silicate domain, which therefore is recyclable. To optimize silicate-metal segregation for recycling BOF-slag, it is suggested (i) bringing the BOF-slag composition within the low-temperature side of the C2S-merwinite-akermanite Alkemade triangle by adding quartz-sand; (ii) reductively heating to 1500-1600 degrees C; and (iii) cooling slowly then quenching to suppress C2S crystallization from melts.

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  • Distribution and hosts of arsenic in a sediment core from the Chianan Plain in SW Taiwan: Implications on arsenic primary source and release mechanisms Reviewed

    Huai-Jen Yang, Chi-Yu Lee, Yu-Ju Chiang, Jiin-Shuh Jean, Yen-Hong Shau, Eiichi Takazawa, Wei-Teh Jiang

    SCIENCE OF THE TOTAL ENVIRONMENT   569   212 - 222   2016.11

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    High arsenic abundance of 50-700 mu g/L in the groundwater from the Chianan Plain in southwestern Taiwan is a well-known environmental hazard. The groundwater-associated sediments, however, have not been geochemically characterized, thus hindering a comprehensive understanding of arsenic cycling in this region. In this study, samples collected from a 250 m sediment core at the centre of the Chianan Plain were analyzed for arsenic and TOC concentrations (N = 158), constituent minerals (N = 25), major element abundances (N = 105), and sequential arsenic extraction (N = 23). The arsenic data show a prevalence of >10 mg/kg with higher concentrations of 20-50 mg/kg concentrated at 60-80 and 195-210 m. Arsenic was extracted mainly as an adsorbate on clay minerals, as a co-precipitate in amorphous iron oxyhydroxide, and as a structural component in clay minerals. Since the sediments consist mainly of quartz, chlorite, and illite, the correlations between arsenic concentration and abundances of K2O and MgO pinpoint illite and chlorite as the major arsenic hosts. The arsenic-total iron correlation reflects the role of chlorite along with the contribution from amorphous iron oxyhydroxide as indicated by arsenic extraction data. Organic matter is not the dominant arsenic host for low TOC content, low arsenic abundance extracted from it, and a relatively low R-2 of the arsenic-TOC correlation. The major constituent minerals in the sediments are the same as those of the upriver metapelites, establishing a sink-source relationship. Composition data from two deep groundwater samples near the sediment core show Eh values and As(V)/As(III) ratios of reducing environments and high arsenic, K, Mg, and Fe contents necessary for deriving arsenic from sediments by desorption from clay and dissolution of iron oxyhydroxide. Therefore, groundwater arsenic was mainly derived from groundwater-associated sediments with limited contributions from other sources, such as mud volcanoes. (C) 2016 Elsevier B.V. All rights reserved.

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  • Sr and Nd Isotopic evidence in metacarbonate rocks for an extinct Island arc-ocean system in East Antarctica Reviewed

    Naho Otsuji, M. Satish-Kumar, Atsushi Kamei, Eiichi Takazawa, Noriyoshi Tsuchiya, G. H. Grantham, Tetsuo Kawakami, Masahiro Ishikawa, Yasuhito Osanai

    JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES   111 ( 3 )   170 - 180   2016.6

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    Chemically precipitated carbonate sediments directly record seawater composition that helps to decode the Earth's paleo-environment, the existence of paleo-oceans, and provide valuable clues on the paleo-tectonic position of continents through Earth's history. In addition, the geochemical and isotopic composition of carbonate rocks have a strong dependence on the depositional tectonic setting and surrounding source rock composition. This was particularly important in the Precambrian, during which biological activity was less prominent and vegetation was virtually absent. Here we present evidence for the existence of an extinct East Antarctic Ocean and its peripheral oceanic island arc system that preceded the formation of the East Antarctic continent in the Neoproterozoic before the final assembly of Gondwana. Applying a multi-element isotope geochemical approach on chemostratigraphically well-constrained metacarbonate rocks collected from the remote Sor Rondane Mountains in East Antarctica, we present a model on carbonate deposition surrounding an island arc system, mid-ocean volcanic islands and a shallow marine continental shelf of a yet unidentified interior Antarctic continent, all of which accreted in the late Neoproterozoic to early Paleozoic to form the present day East Antarctic continent prior to the final amalgamation of Gondwana supercontinent. Our results support the presence of an oceanic island arc system that might have separated the Mozambique ocean and East Antarctic ocean.

    DOI: 10.2465/jmps.151029a

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  • CO2 sequestration utilizing basic-oxygen furnace slag: Controlling factors, reaction mechanisms and V-Cr concerns Reviewed

    Tung-Hsin Su, Huai-Jen Yang, Yen-Hong Shau, Eiichi Takazawa, Yu-Chen Lee

    JOURNAL OF ENVIRONMENTAL SCIENCES   41   99 - 111   2016.3

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    Basic-oxygen furnace slag (BOF-slag) contains >35% CaO, a potential component for CO2 sequestration. In this study, slag-water-CO2 reaction experiments were conducted with the longest reaction duration extending to 96 hr under high CO2 pressures of 100-300 kg/cm(2) to optimize BOF-slag carbonation conditions, to address carbonation mechanisms, and to evaluate the extents of V and Cr release from slag carbonation. The slag carbonation degree generally reached the maximum values after 24 hr slag-water-CO2 reaction and was controlled by slag particle size and reaction temperature. The maximum carbonation degree of 71% was produced from the experiment using fine slag of <= 0.5 mm under 100 degrees C and a CO2 pressure of 250 kg/cm(2) with a water/slag ratio of 5. Vanadium release from the slag to water was significantly enhanced (generally >2 orders) by slag carbonation. In contrast, slag carbonation did not promote chromium release until the reaction duration exceeded 24 hr. However, the water chromium content was generally at least an order lower than the vanadium concentration, which decreased when the reaction duration exceeded 24 hr. Therefore, long reaction durations of 48-96 hr are proposed to reduce environmental impacts while keeping high carbonation degrees. Mineral textures and water compositions indicated that Mg-wustite, in addition to CaO-containing minerals, can also be carbonated. Consequently, the conventional expression that only considered carbonation of the CaO-containing minerals undervalued the CO2 sequestration capability of the BOF-slag by similar to 20%. Therefore, the BOF-slag is a better CO2 storage medium than that previously recognized. (C) 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

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  • Across-arc variations in geochemistry of Oligocene to Quaternary basalts from the NE Japan arc: Constraints on source composition, mantle melting and slab input composition Reviewed

    Shuto, K., Nohara-Imanaka, R., Sato, M., Takahashi, T., Takazawa, E., Kawabata, H., Takanashi, K., Ban, M., Watanabe, N., Fujibayashi, N.

    Journal of Petrology   56 ( 11 )   2257 - 2294   2015.12

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  • Decoupling of the Lu-Hf, Sm-Nd, and Rb-Sr isotope systems in eclogites and a garnetite from the Sulu ultra-high pressure metamorphic terrane: Causes and implications Reviewed

    Yung-Hsin Liu, Huai-Jen Yang, Eiichi Takazawa, Madhusoodhan Satish-Kumar, Chen-Feng You

    LITHOS   234   1 - 14   2015.10

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    The whole-rock Hf, Sr and Nd isotope data of five high-Fe-Ti eclogites, nine high-Al edogites, and a garnetite from the Sulu ultrahigh pressure (UHF) metamorphic terrane at eastern China were analyzed to resolve the causes for the decoupling of the Lu-Hf, Sm-Nd, and Rb-Sr isotope systems in these UHP rocks and to infer their protolith characteristics. Seven of the nine high-Al eclogites define an Rb-87/Sr-86-Sr-87/Sr-86 errorchron age of 192 +/- 43 Ma (MSWD = 2.8), which is within the time span of retrograde metamorphism despite the large uncertainty. The high-Fe-Ti eclogites and garnetite, however, have low Rb-87/Sr-86 ratios of <0.031 with scattered Sr-87/Sr-86 ratios of 0.7042-0.7058. Accordingly, it is inferred that the Rb-Sr isotope system in the samples reflects the effects of processes postdating the UHP metamorphism. Despite having different constituent mineral assemblages and whole rock geochemistry, the samples, however, define a Sm-147/Nd-144-Nd-143/Nd-144 errorchron age of 232 +/- 36 Ma (MSWD = 4.6). Although the uncertainty of +/-36 Ma implies incomplete Nd isotope equilibrium among the samples, the large overlap between this errorchron age span and the mineral isochron ages of 245-210 Ma for the UHP metamorphism indicates the control of peak metamorphism on the Sm-Nd isotope system. The incomplete Nd isotope re-equilibration was accompanied by metamorphic modification on the Sm/Nd ratios as indicated by the U-shaped LREE patterns. The initial epsilon(Nd)(780) values of the protolith rocks calculated from the Sm/Nd ratios of the samples deviate from the igneous initial epsilon(Nd)(t)-epsilon(Hf)(t) trend to significantly lower values, consistent with the metamorphic increase in the Sm/Nd ratios. In contrast, the Lu/Hf ratios are generally within the range for basalts and do not vary systematically with the Hf-176/Hf-177 ratios. The protolith epsilon(Hf)(780) values calculated from the Lu/Hf ratios of the samples are nearly identical to the initial epsilon(Hf)(t) values of the -780 Ma magmatic zircon cores from the Yangtze craton, suggesting the dominance of protolith characteristics on the Lu-Hf isotope system, Being controlled by different processes, the Rb-Sr, Sm-Nd, and Lu-Hf isotope systems of the investigated samples are therefore decoupled. The epsilon(Nd)(220)-epsilon(Hf)(220) compositions of the samples deviate from the epsilon(Nd)(t)-epsilon(Hf)(t) trend of intraplate lavas to high epsilon(Hf)(220) at a given epsilon(Nd)(220) and are within the arc lava field. The protolith epsilon(Nd)(780)-epsilon(Hf)(780) compositions calculated from metamorphic initials using igneous Sm/Nd and Lu/Hf ratios show a similar distribution pattern, strengthening the arc affinity of the eclogites. These arc signatures together with the felsic-mafic bimodal geochemical features of the UHF rocks from the Sulu terrane are explained as the characteristics of protoliths generated by backarc rifting. (C) 2015 Elsevier B.V. All rights reserved.

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  • The influence of melt infiltration on the Li and Mg isotopic composition of the Horoman Peridotite Massif Reviewed

    Yi-Jen Lai, Philip A. E. Pogge von Strandmann, Ralf Dohmen, Eiichi Takazawa, Tim Elliott

    GEOCHIMICA ET COSMOCHIMICA ACTA   164   318 - 332   2015.9

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    We have analysed the Li and Mg isotope ratios of a suite of samples from the Horoman Peridotite Massif. Our results show that most Li and all Mg isotopic compositions of the Horoman peridotites are constant over 100 metres of continuous outcrop, yielding values for pristine mantle of delta Li-7 = 3.8 +/- 1.4 parts per thousand (2SD, n = 9), delta Mg-25 = -0.12 +/- 0.02 parts per thousand and delta Mg-26 = -0.23 +/- 0.04 parts per thousand (2SD, n = 17), in keeping with values for undisturbed mantle xenoliths. However, there are also some anomalously low delta Li-7 values (-0.2 parts per thousand to 1.6 parts per thousand), which coincide with locations that show enrichment of incompatible elements, indicative of the prior passage of small degree melts. We suggest Li diffused from infiltrating melts with high [Li] into the low [Li] minerals and kinetically fractionated Li-7/Li-6 as a result. Continued diffusion after the melt flow had ceased would have resulted in the disappearance of this isotopically light signature in less than 15 Ma. In order to preserve this feature, the melt infiltration must have been a late stage event and the massif must have subsequently cooled over a maximum of similar to 0.3 Ma from peak temperature (950 degrees C, assuming the melts were hydrous) to Li closure temperature (700 degrees C), likely during emplacement. The constant delta Mg-26 values of Horoman peridotites suggest that chemical potential gradients caused by melt infiltration were insufficient to drive associated delta Mg-26 fractionation greater than our external precision of 0.03 parts per thousand. (C) 2015 Elsevier Ltd. All rights reserved.

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  • Compositional and Sr-Nd-Hf isotopic variations of Baijingsi eclogites from the North Qilian orogen, China: Causes, protolith origins, and tectonic implications Reviewed

    Choon-Muar Ker, Huai-Jen Yang, Jianxin Zhang, Yen-Hong Shau, Chia-Ju Chieh, Fancong Meng, Eiichi Takazawa, Chen-Feng You

    GONDWANA RESEARCH   28 ( 2 )   721 - 734   2015.9

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    Eclogites from the Baijingsi area in the North Qilian orogen at NW China were analyzed for major and trace element abundances as well as Sr, Nd, and Hf isotope ratios to evaluate the impacts from subduction processes on these compositional parameters and to reveal the complexity in protolith characteristics. The major element compositions of the Baijingsi eclogites are within the ranges for basalts. However, the absence of systematic variations among major oxides indicates varying extents of metamorphic modifications. Seven samples are characterized by profound Nb and Ta depletions. Six of them form coherent trends in the La versus Th, HFSE, and LREE plots. They are classified as the Group 1 samples. Other eight samples, referred to as the Group 2 samples, define distinct La-Zr and La-Sm trends and have flat variation patterns with slight Th-Nb-Ta-LREE depletions in the primitive mantle-normalized multiple-element diagram. Group 1 dominates the Sr-87/Sr-86-Rb-87/Sr-86, Nd-143/Nd-144-Sm-147/Nd-144 and Hf-176/Hf-177-Lu-176/Hf-177 trends for relatively larger variations in the isotope and abundance ratios. Based on the errorchron ages from the samples, closure temperatures of the isotope systems, and isotope ratio versus 1/X plots (e.g., Sr-87/Sr-86-1/Sr), it is inferred that the Rb-Sr isotope system was subjected to metamorphic modification, whereas the Sm-Nd and Lu-Hf isotope systems mainly reflect protolith characteristics. In addition to the Nb and Ta depletions, the Group 1 samples generally have epsilon(Hf)(510) values (protolith initial at 510 Ma) higher than those of MORB at a given epsilon(Nd)(510), reflecting derivation from relatively high Lu/Hf ratio sources. They also plot within the fields for arc lavas in the Ta/Yb-Th/Yb and Th-Ta-Hf/3 diagrams. All these features are consistent with derivation from protoliths of an arc origin. In contrast, the Group 2 samples have eNd(510) values slightly higher than those of the Group 1 samples at a given epsilon(Hf)(510), plotting on the low epsilon(Nd)(510) margin of the MORB field. They also deviate from the Ta/Yb-Th/Yb trend defined by MORE and OIB toward higher Th/Yb values within the fields of back-arc basin basalts. Therefore, it is inferred that the protoliths of the Group 2 samples were generated as back-arc basin basalts possibly associated with the protoliths of the Group 1 samples in a common supra-subduction zone. The epsilon(Nd)(510)-epsilon(Hf)(510) relationship of the Baijingsi eclogites shows an affinity to the Indian ocean type mantle, implying protolith generation at the southern hemisphere on the margin or a fragment of the Gondwana continent, most likely in the Qilian Block. Based on the current tectonic configuration, a southward subduction is required for protolith generation and might eclogitize the arc protoliths by subduction erosion. Alternatively, the northward subduction in a bidirectional subduction system might become dominant during the amalgamation of the Qilian Block and the North China Craton to eclogitize the arc protoliths in the Qilian Block. Resolving these two possibilities requires more petrological, geochemical, and structural evidence from the North Qilian orogen. (C) 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

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  • Melt extraction and metasomatism recorded in basal peridotites above the metamorphic sole of the northern Fizh massif, Oman ophiolite Reviewed

    Masako Yoshikawa, Marie Python, Akihiro Tamura, Shoji Arai, Eiichi Takazawa, Tomoyuki Shibata, Akira Ueda, Tsutomu Sato

    TECTONOPHYSICS   650   53 - 64   2015.5

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    The Oman ophiolite is one of the best preserved sections of oceanic crust and upper mantle worldwide, and consists of multiple massifs that lie along more than 400 km of the Arabian coast. In the northernmost massifs, the oceanic crust preserves a record of polygenetic magmatism from mid-ocean ridge to subduction-related stages. The lherzolites and clinopyroxene (Cpx)-rich harzburgites of the Fizh block are located a few tens to a hundred meters above the metamorphic sole of the ophiolite and the geochemistry of these Cpx-rich peridotites provides evidence of a genetic link between oceanic crust and mantle. These Cpx-rich peridotites contain olivine with a restricted range of forsterite contents (90-91), but variable Cr-spinel Cr# (Cr/(Cr + Al) atomic ratio) values (0.12-0.33), suggesting that these Cpx-rich peridotites have undergone variable degrees of melt extraction. Cpxs within the Cpx-rich peridotites have chondrite-normalised trace element variation patterns that slope either gently or steeply between the heavy rare earth elements (REEs) and the middle REEs ((Sm/Yb)(N) = 0.08-0.55, where N chondrite-normalised) and are enriched in highly incompatible elements such as Rb, Ba and Nb. This Cpx chemistry can be explained by a polygenetic evolution whereby an initial 4-12% of melt was extracted from the depleted mantle source before this mantle was metasomatised by interaction with fluids derived from dehydration of the metamorphic sole during subduction initiation and obduction. A comparison between Nd-143/Nd-144 versus Sm-147/Nd-144 for Cpx in the Fizh basal Cpx-rich peridotites and a mineral-whole rock Sm-Nd isochron for a gabbro from the same massif suggests a genetic link between crustal and mantle rocks in this area. In addition, Cpxs within the basal Cpx-rich peridotites have highly variable Sr isotopic compositions that are indicative of a significant contribution of seawater from the metamorphic sole, originally derived from subducted oceanic crustal material. (C) 2014 Elsevier B.V. All rights reserved.

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  • Repeated magmatism at 34 Ma and 23-20 Ma producing high magnesian adakitic andesites and transitional basalts on southern Okushiri Island, NE Japan arc Reviewed

    Makoto Sato, Kenji Shuto, Rikako Nohara-Imanaka, Eiichi Takazawa, Yasuhito Osanai, Nobuhiko Nakano

    LITHOS   205   60 - 83   2014.9

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    The southern part of Okushiri Island in the present-day back-arc margin of the NE Japan arc is one of the rare convergent plate boundaries where similar magma types (high-magnesian adakitic andesite (HMAA) and high-TiO2 basalt (HTB)) have been erupted concurrently at more than one time. Oligocene HMAA can be divided into two types: HMAA-I is characterized by high Sr/Y and low Y, and HMAA-II by relatively low Sr/Y and high Y. HMAA-I is primitive in terms of MgO (8.5 wt.%), Mg# (67), Ni (232 ppm) and Cr (613 ppm) contents, and the most Mg-rich olivine phenocrysts plot within the mantle olivine array in terms of Fo and NiO. The similar Cr versus Ni relations of types I and II HMAA indicate some interaction of slab-derived adaldtic melts with mantle peridotite, whereas Ni contents are higher than those of most boninites derived by partial melting of mantle peridotite at a given Cr content Types I and II HMAA have more enriched Stand Nd isotopic compositions than N-MORB. The petrography and geochemistry of these rocks, combined with published results on the genesis of high-magnesian andesite (HMA) indicate that types I and II HMAA could be produced by interaction of slab (N-MORB and sediment)derived adakitic melts with mantle peridotite. The comagmatism of HMAA and HTB is ascribed to the following model. A cool, less hydrous, adakite magma (spherical diapir) would rise from the subducting slab (Pacific Plate) and become more hydrous as a result of its interaction with overlying hydrous peridotite. This hydrated adakitic diapir further ascends and is heated on entering the overlying mantle wedge. Subsequently, the temperature and H2O gradients in the ascending adakitic diapir and surrounding mantle peridotite would have been established. The HTB magma segregated from the surrounding mantle peridotite region (high temperature and low H2O content) at a depth of 60 km or more, whereas the adakitic diapir (low temperature and high H2O content) continued to rise, with its chemical composition modified due to interaction with the surrounding mantle peridotite. Type I HMAA then segregated at about 50 km.The most attractive tectono-magmatic model to account for production of adakitic magma at two different periods in the same cool subduction zone region involves upwelling of depleted hot asthenosphere into the subcontinental lithosphere beneath the back-arc margin of the NE Japan arc, coincident with back-arc rifting which took place at the initiation of the Japan Sea opening. The unusually high temperature conditions established in the mantle wedge due to upwelling of depleted hot asthenosphere caused partial melting of a limited part of the cool oceanic crust subducting beneath the NE Japan arc, resulting in the generation of adakitic magma. (C) 2014 Elsevier B.V. All rights reserved.

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  • A kilometre-scale highly refractory harzburgite zone in the mantle section of the northern oman ophiolite (fizh block): Implications for flux melting of oceanic lithospheric mantle Reviewed

    Nami Kanke, Eiichi Takazawa

    Geological Society Special Publication   392 ( 1 )   229 - 246   2014

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    We report the major element compositions of constituent minerals in 278 harzburgites and of 101 whole rocks from the northern Fizh mantle section in the northern Oman Ophiolite to investigate the formation and evolution of oceanic lithospheric mantle. Olivine Fo varies from 90 to 92 whereas spinel Cr# (=Cr/(Cr + Al) atomic ratio) varies from 0.15 to 0.78. The Cr# of spinels in a large number of harzburgites exceeds 0.6, which is the upper bound for abyssal peridotites. In the northern Fizh mantle section, highly refractory harzburgites with spinel Cr# greater than 0.7 are distributed in a 3-km-wide band along a NW-SE-striking shear zone. We infer a two-stage depletion process in the northern Fizh mantle section. In the first stage, asthenospheric mantle was partially melted beneath a mid-ocean ridge, producing a harzburgitic residual column. In the second stage during detachment of oceanic lithosphere an H2O-rich fluid, released from the metamorphic sole due to thermal metamorphism of altered oceanic crust, extensively infiltrated the northern Fizh mantle section where the ridge segment boundary region was previously located. The residual harzburgites were subjected to flux melting, resulting in a highly refractory harzburgite zone with spinel Cr# greater than 0.7. © The Geological Society of London 2014.

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  • Petrological nature and origin of the ultramafic complex in the basal part of the Salahi mantle section, the Oman ophiolite Reviewed

    野本有希, 高澤栄一

    岩石鉱物科学   42 ( 3 )   123-135 (J-STAGE) - 135   2013

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    Extensive lenticular-shaped ultramafic complexes that are composed of dominant amount of dunite associated with harzburgite and irregular-shaped pyroxenite cumulates, occur in the basal part of the Salahi mantle section in the northern Oman ophiolite. Petrologic characteristics such as rock types, textures and mineral compositions were examined to understand the origin of the ultramafic complex. Peridotites exhibit coarse-granular to very coarse-granular texture with grain size greater than five millimeters. The Cr#[=Cr/(Cr+Al) atomic ratio] of spinels in harzburgites ranges from 0.56 to 0.72, and is most frequent at 0.64-0.66 while spinel Cr# of dunites ranges from 0.61 to 0.84, and is most frequent at 0.76-0.82. The origin of voluminous dunite with high Cr# spinel can be explained by flux melting of residual harzburgite as a result of infiltration of large amount of fluid from the base of the ophiolite during oceanic thrusting. Dunites with very coarse-granular texture also support this hypothesis. The dunites in the central part of the complex tend to have both olivine Fo content and spinel Cr# greater than those in the host harzburgites. We speculate that not only orthopyroxene but also olivine were consumed during flux melting in this region resulted in the formation of voluminous dunites in the core of the complex. On the other hand, the dunites from the periphery of the complex have olivine with Fo content lower than those in the host harzburgites indicating precipitation of olivine from the melt. Moreover, crystallization of pyroxene formed numerous pyroxenites in this region. The southern part of the Salahi mantle section has been considered as a paleo-ridge segment end region. Our results support that the occurrence of highly refractory peridotites is spatially related to the segment end region in the northern Oman ophiolite.<br>

    DOI: 10.2465/gkk.120624

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  • Scientific drilling and related research in the samail ophiolite, sultanate of Oman Reviewed

    Peter Kelemen, Ali Al Rajhi, Marguerite Godard, Benoit Ildefonse, Jürgen Köpke, Chris MacLeod, Craig Manning, Katsu Michibayashi, Sobhi Nasir, Everett Shock, Eiichi Takazawa, Damon Teagle

    Scientific Drilling   ( 15 )   64 - 71   2013

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    DOI: 10.2204/iodp.sd.15.10.2013

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  • スコットランド南東部シッカー岬とハットンの不整合 Reviewed

    道林克禎, 森下知晃, 村山雅史, 西弘嗣, 尾鼻浩一郎, 鈴木庸平, 高澤栄一, 山田泰広, 横山祐典

    地質学雑誌   118 ( 11 )   IX-X - X   2012.11

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    DOI: 10.5575/geosoc.118.11.IX_X

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  • Preface Reviewed

    MORISHITA Tomoaki, ABE Natsue, MIZUKAMI Tomoyuki, OZAWA Kazuhito, TAKAZAWA Eiichi

    Japanese Magazine of Mineralogical and Petrological Sciences   41 ( 5 )   171 - 173   2012.9

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    &amp;nbsp;&amp;nbsp;How much do we know the Earth&#039;s mantle? We would like to make clear what we want to know, what we can know and what we will be able to know the Earth&#039;s mantle. This special issue focuses on recent scientific advances in serpentinization, pressure-temperature paths including thermal history of the earth, tectono-magmatic processes, geochemical recycling, rheology and chemical compositions of the Earth&#039;s mantle based on analyses of mantle-derived materials including volcanic rocks. These topics provide useful information for a wide range of earth scientific communities.&lt;br&gt;

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  • Melting and reaction in an incipient subarc mantle as inferred from the spatial compositional variability in the mantle section of the Oman ophiolite Reviewed

    Eiichi Takazawa

    Japanese Magazine of Mineralogical and Petrological Sciences   41 ( 6 )   257 - 266   2012

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    The Oman ophiolite is a remnant of Neo-Tethyan oceanic lithosphere that has been modified by arc-related magmatism during oceanic thrusting prior to the obduction to the Arabian continent. To understand the formation of oceanic mantle lithosphere at a spreading ridge and subsequent modification at an incipient subduction zone a km-scale mineral chemical mapping of the mantle section was conducted in the Fizh and Salahi blocks in the northern Oman ophiolite. The range of spinel Cr#[= Cr/(Cr + Al) atomic ratio] in harzburgites becomes wider from the region of paleo-ridge segment center to the margin. In the northern part, where a paleo-ridge segment margin was inferred, refractory harzburgites with spinel Cr# greater than 0.7 are abundant and are distributed as a band (3 km in width) extending from the basal thrust to the Moho. Such high refractory harzburgites are associated with thick dunite bands in which spinel Cr# is also high (greater than 0.7). Dunites in the Fizh and Salahi mantle sections have spinel with Cr# ranging from 0.45 to 0.8 and tend to have higher spinel Cr# than the harzburgites. Moreover, the dunites with high Cr# spinel (greater than 0.7) are abundant in the basal part of the mantle section. The distribution of refractory har-zburgite and dunite in the northern Oman ophiolite can be modeled as follows. During oceanic thrusting the Oman ophiolite was displaced above an incipient subduction zone. The fluid released from metamorphic sole due to thermal metamorphism of altered oceanic crust in-iltrated into the mantle section. Dunite channels may have acted as pathways for luid in-iltration from the base of the ophiolite, which was instrumental for lux melting of wallrock harzburgite. The presence of the high refractory harzburgites in the northern Fizh mantle section implies that the iniltration of luid from the base of ophiolite was extensive in the ridge segment boundary region. © 2012, Japan Association of Mineralogical Sciences. All rights reserved.

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  • The mohole: A crustal journey and mantle quest, workshop in Kanazawa, Japan, 3-5 June 2010 Reviewed

    Benoît Ildefonse, Natsue Abe, Donna K. Blackman, J. Pablo Canales, Yoshio Isozaki, Shuichi Kodaira, Greg Myers, Kentaro Nakamura, Mladen Nedimovic, Alexander C. Skinner, Nobukazu Seama, Eiichi Takazawa, Damon A.H. Teagle, Masako Tominaga, Susumu Umino, Douglas S. Wilson, Masaoki Yamao

    Scientific Drilling   10, 56-63 ( 10 )   56 - 63   2010.9

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    DOI: 10.2204/iodp.sd.10.07.2010

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  • Shallow Mantle Composition and Dynamics: Fifth International Orogenic Lherzolite Conference Reviewed

    Martin Menzies, Peter Kelemen, Henry Dick, Jean-Louis Bodinier, Francoise Boudier, Greg Hirth, Tim Grove, Andrea Tommasi, Eiichi Takazawa

    JOURNAL OF PETROLOGY   51 ( 1-2 )   3 - 7   2010.1

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    DOI: 10.1093/petrology/egp098

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  • Primary melting sequence of a deep (&gt; 250 km) lithospheric mantle as recorded in the geochemistry of kimberlite-carbonatite assemblages, Snap Lake dyke system, Canada Reviewed

    A. M. Agashev, N. P. Pokhilenko, E. Takazawa, J. A. McDonald, M. A. Vavilov, T. Watanabe, N. V. Sobolev

    Chemical Geology   255 ( 3-4 )   317 - 328   2008.10

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    Geochemistry of kimberlites and associated carbonatites from the Snap Lake dyke system, Slave craton, Canada, shows that kimberlites are similar, but not identical to Group I kimberlites from South Africa and Siberia. Snap Lake kimberlites are enriched in most incompatible elements such as U, Th, Nb and LREE (up to 1400 times chondritic abundances), and are weakly differentiated relative to primitive mantle in their Sr and Nd isotope compositions. The Snap Lake carbonatites and kimberlites are enriched or depleted in certain trace elements relative to each other. Carbonatites are depleted in Cs, Rb, K, Ta and Ti but enriched in U, Sr, P, Zr, Hf, middle and heavy REEs relative to kimberlites. The observed element distributions are not consistent with experimental data on distribution of trace elements between immiscible carbonate and silicate liquids. However, the chemistry of these rocks shows a continuous systematic change from carbonatites to kimberlites, suggesting their genetic relationship. The range of major element concentrations from low SiO2 (3 wt.%) magmas to typical kimberlites are in excellent agreement with experimental data for melting of carbonated lherzolite at high pressure. Carbonatites have significantly superchondritic Nb/Ta (22-81) and Zr/Hf (57-128) ratios, which systematically decrease with increase of SiO2. Modeling of partial melting requires that the source for Snap Lake dyke rocks was enriched in incompatible elements but depleted in HREE relative to the primitive mantle. The most appropriate source rocks are metasomatically enriched peridotites of the deep lithospheric mantle roots. In the melting sequence of this source, the incipient magma was carbonatitic in composition but subsequently became kimberlitic as the degree of partial melting increased to 1%. Rocks of the Snap Lake dyke represent a natural example of primary melting process within a deep (&gt
    250 km) lithospheric mantle. © 2008 Elsevier B.V. All rights reserved.

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  • Origin of layering observed in the Horoman peridotite complex, Japan

    Niida Kiyoaki, Takasawa Eiichi

    The Journal of the Geological Society of Japan   113   S167 - S184   2007

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    DOI: 10.5575/geosoc.113.S167

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  • Corundum-bearing mafic granulites in the Horoman (Japan) and Ronda (Spain) peridotite massifs: Possible remnants of recycled crustal materials in the mantle Reviewed

    Morishita, T., Takazawa, E., Arai, S., Obata, M., Kodera, T., Gervilla, F.

    Island Arc   15 ( 1 )   2 - 3   2006.3

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    DOI: 10.1111/j.1440-1738.2006.00517.x

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  • Geochemical secular variation of magma source during Early to Middle Miocene time in the Niigata area, NE Japan: Asthenospheric mantle upwelling during back-arc basin opening Reviewed

    K Shuto, H Ishimoto, Y Hirahara, M Sato, K Matsui, N Fujibayashi, E Takazawa, K Yabuki, M Sekine, M Kato, AI Rezanov

    LITHOS   86 ( 1-2 )   1 - 33   2006.1

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    In the Niigata region of the NE Japan arc, basaltic and intermediate to felsic volcanic rocks (silicic andesite, dacite and rhyolite) have been produced during the Early Miocene, Middle Miocene and Pliocene ages, spanning the pre-Japan Sea opening to post-opening stages. Early Miocene basaltic rocks are characterized by enriched Sr and Nd isotopic signatures (initial Sr-87/Sr-86 (SrI) = 0.70557 to 0.70592 and initial Nd-143/Nd-144 (NdI)=0.51255 to 0.51262), whereas Middle Miocene and Pliocene basaltic rocks are slightly enriched than MORB in terms of SrI (0.70314-0.70416) and NdI (0.51286-0.51310). Early Miocene basaltic rocks are also characterized by higher abundances of HFSE and LREE, and higher Zr/Y compared to Middle Miocene and Pliocene basaltic rocks. The geochemical features of Early Miocene basaltic rocks are almost identical to those of basaltic rocks found in continental rift zones, such as the Rio Grande rift. The different geochemical signatures of Early and Middle Miocene basaltic rocks can be ascribed to the geochemical differences in the mantle source. Apart from andesitic rocks of the Kakuda area, most of Early and Middle Miocene intermediate to felsic volcanic rocks from the Niigata region show significantly higher SrI values (0.70673-0.70773) and lower NdI values (0.51234-0.51254) than Early Miocene basaltic rocks, indicating a lower crustal origin for these more felsic volcanic rocks.

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  • Compositional continuity and discontinuity in the Horoman peridotite, Japan, and its implication for melt extraction processes in partially molten upper mantle Reviewed

    M Obata, E Takazawa

    JOURNAL OF PETROLOGY   45 ( 2 )   223 - 234   2004.2

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    A hypothetical model is proposed to explain the origin of compositional discontinuities in the layering observed in orogenic lherzolites. The observed collinearity of the whole-rock peridotite compositions is best explained in terms of partial melting and melt segregation. The presence of chemical discontinuities implies that melt segregation includes an abrupt and discontinuous process. A kg concept in the model is the topological transformation of melt geometry in partially molten rocks responding to the equality and inequality of the fluid pressure and solid pressure, which may be realized in a gravitational field. It is emphasized that the percolation threshold is a critical boundary, beyond which a rapid microstructural change occurs in response to the change of local fluid pressure, thus causing a rapid increase of permeability. The model implies that the mode of melting is closer to batch melting than to fractional melting in the upper mantle.

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  • P-211 Hybridization of dunite and gabbroic materials observed in Hole 1271B, ODP Leg 209

    Takazawa Eiichi, Abe Natsue, Kikawa Eiichi

    Annual Meeting of the Geological Society of Japan   2004   265 - 265   2004

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    DOI: 10.14863/geosocabst.2004.abst.0_265_1

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  • Geochemistry and origin of the basal lherzolites from the northern Oman ophiolite (northern Fizh block) Reviewed

    E Takazawa, T Okayasu, K Satoh

    GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS   4   2003.2

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    [1] Abundances of major and trace elements in whole rocks and minerals in lherzolites and harzburgites from the northern Oman ophiolite are used to understand the mantle processes creating compositional variation in oceanic lithospheric mantle. Detailed mapping shows that lherzolites occur near the base of a mantle section in the northern Fizh block. Geochemical analyses identify two types of basal lherzolite. The first type (Type I lherzolite) displays porphyroclastic microstructure and occurs sporadically in the basal mylonite zone. Whole rock and clinopyroxene are highly depleted in incompatible elements such as Na, Ti, Zr, and rare earth elements (REE). The chondrite-normalized patterns of Type I lherzolites show steep slopes from heavy REE (HREE) to light REE (LREE) that are ascribed to melt extraction, up to 12-18%, from a source containing a small amount of garnet. The chondrite-normalized patterns have slight enrichment in LREE relative to the patterns expected for residues of partial melting thereby indicating reaction with a LREE-enriched melt or fluid at a low melt/rock ratio. The second type (Type II lherzolite) shows mylonitic microstructure and only occurs at the contact between the mantle section and the metamorphic sole. Abundances of incompatible elements in whole rocks and clinopyroxenes are greater than those of Type I lherzolites, and clinopyroxenes in Type II lherzolites have high Na(2)O contents (&gt; 1 wt.%). To a first approximation, the high Na content of clinopyroxenes and whole rocks and the LREE-depleted, chondrite-normalized whole rock REE patterns are consistent with Type II lherzolite being in equilibrium with a midocean ridge basalt (MORB)-type melt at relatively high pressure (&gt; 2 GPa). However, the flatness of chondrite-normalized patterns for middle and heavy REE are inconsistent with residual garnet peridotite. The characteristics of Type II lherzolites are better explained by a mixing process in which residual peridotite was refertilized by addition of a LREE-depleted melt. The large compositional gradient near the basal thrust in the northern Fizh block may have recorded a transient state in which the degree of partial melting was progressively decreased as a result of reducing mantle temperature and upwelling rate. This scenario is consistent with the inferred failing ridge associated with a transform zone in the western side of the northern Fizh block proposed by Nicolas et al. [2000]. In the detachment stage of the Oman ophiolite, a small amount of ascending melt may have crystallized near the basal part of mantle section thereby forming Type II lherzolites. Basal lherzolites and their spatial chemical variations in the northern Fizh block may provide a key for understanding the processes of ridge segmentation and detachment at fast spreading ridges.

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  • Model of layering formation in a mantle peridotite (Horoman,Hokkaido, Japan) Reviewed

    Toramaru, A., Takazawa, E., Morishita, T., Matsukage, K.

    Earth and Planetary Science Letters   185 ( 3-4 )   299 - 313   2001.3

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    The Horoman peridotite complex exhibits a conspicuous layered structure. It is found, from the geological and petrological survey, that the pattern of layering has three characteristics: symmetry, asymmetry (subtly collapsed symmetry) and scale invariance. Especially, symmetric and asymmetric patterns clearly recognized in the sequence of mafic layers at the Northern ridge of Apoi-dake peak, and at the Western ridge of Bozu-yama peak are noticeable. We present a simple mathematical model describing stretching (thinning) and folding during deformation that accounts for the three characteristics. The model quantitatively reproduces the slope in cumulative frequency distribution of the width of mafic layers and indicates that the frequency distribution is strongly influenced by the spatial strain contrast. Applying the model result to the observational data for mafic layers, it is found that the strain contrast approximately ranges several to 10 times between regions with the highest and the lowest strain rates. © 2001 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0012-821X(00)00382-4

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  • Re-Os isotopes in the Horoman peridotite: Evidence for refertilization? Reviewed

    AE Saal, E Takazawa, FA Frey, N Shimizu, Hart, SR

    JOURNAL OF PETROLOGY   42 ( 1 )   25 - 37   2001.1

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    Re-Os isotopic data for 20 samples from a well-characterized 140 m section across a layered sequence, ranging from plagioclase lherzolite through lherzolite to harzburgite, of the Horoman peridotite show: (1) a range in Os-187/Os-188 ratios (from 0.1158 to 0.1283) similar to that reported for other peridotitic massifs, thereby suggesting that the processes responsible for the Re-Os isotopic variation at the meter-scale and the whole-massif scale are similar; (2) that the Os isotopic ratio is controlled by the Re content through radiogenic ingrowth over a period of similar to0.9 Gy. The ultramafic and some of the mafic rocks (Type I layers)from the Horoman massif define an 'apparent age' of 1.12 +/- 0.24 Ga in the Re-OS isochron diagram, within error of the previously reported age of 833 +/- 78 Ma based on Sm-Nd isotopes. Although the Re-Os isotopic data do not define an isochron, the consistency of the similar to 900 Ma age defined by both isotopic systems suggests that this age has a geologic meaning and that mafic (Type I layers) and ultramafic rocks are genetically related, A plausible explanation for the genetic relationship between the mafic and ultramafic rocks, the meter-scale compositional variations from lherzolite to plagioclase lheriolite, the suprachondritic Re-187/Os-188 ratios in some fertile peridotites, and the oldest RE depletion model age of similar to1.86 Ga obtained for Horoman rocks is a refertilization process involving reaction of a mid-ocean ridge basalt-like magma with depleted lithospheric mantle at similar to 900 Ma.

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  • Whole rock compositional variations in an upper mantle peridotite (Horoman, Hokkaido, Japan): Are they consistent with a partial melting process? Reviewed

    E Takazawa, FA Frey, N Shimizu, M Obata

    GEOCHIMICA ET COSMOCHIMICA ACTA   64 ( 4 )   695 - 716   2000.2

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    Whole rock major and trace element abundances of the Horoman peridotites were used to understand processes forming lithological and compositional variations in the upper mantle. Similar to other orogenic peridotites, Horoman peridotites range from fertile lherzolites (3 to 4% Al(2)O(3) and CaO) to depleted harzburgites (similar to 0.5% Al(2)O(3) and CaO). Abundances of major oxides and compatible to moderately incompatible elements vary systematically with variations in MgO content. Such trends are commonly interpreted as indicating that the peridotites formed as residues from varying degrees of partial melting. The fertile end of these trends coincides with estimates of primitive mantle composition. Because of a mismatch between experimental melting trends for spinel peridotite, especially the Na(2)O-MgO trend, the compositional variations of Horoman peridotites are not consistent with formation as residues from partial melting of spinel peridotite. Non-Linear trends in minor and trace element versus major element abundance diagrams also preclude a two-component mixing model. Recent melting experiments on garnet peridotite demonstrate that at 3 GPa the near-solidus peridotite has a large amount of subcalcic clinopyroxene (ca. 27%) coexisting with small amount of garnet (ca. 2%). Residues from polybaric melting of such garnet peridotite are consistent with the abundance variations of major and moderately incompatible elements, such as Na and heavy rare-earth elements, in the Horoman peridotites. A similar conclusion is applicable to other orogenic peridotites such as the Ronda peridotite because their major element compositional variations are similar to the Horoman peridotite. Copyright (C) 2000 Elsevier Science Ltd.

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  • Permian brachiopods from the Okutadami area, near the boundary between Niigata and Fukushima Prefectures, central Japan and their tectonic implications Reviewed

    Tazawa Jun-ichi, Ando Susumu, Furuhashi Shinya, Furuta Kozue, Okayasu Toshie, Shimura Toshiaki, Takazawa Eiichi, Tateishi Masaaki, Watanabe Satoshi, Yamamoto Kazumi, Yamamoto Ryo, Toyoshima Tsuyoshi, Okochi Makoto

    Journal of the Geological Society of Japan   105 ( 10 )   729 - 732   1999.10

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    The following four brachiopod species are newly recognized from the Okutadami area, central Japan : Anemonaria sp., Yokovlevia sp., Spiriferella sp. and Attenuatella sp. These brachiopods indicate a late Middle Permian (Midian) in age. The Okutadami fauna, consisting of both the Boreal- and Bipolar-type genera, is the first documented Permian Boreal brachiopod fauna in Japan. The occurrence of the Boreal brachiopod fauna from the Okutadami area suggests that the fossil-bearing rocks were formed at the northernmost part of Japan in the Permian time.

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  • Non-chondritic platinum-group element ratios in oceanic mantle lithosphere: petrogenetic signature of melt percolation? Reviewed

    M Rehkamper, AN Halliday, J Alt, JG Fitton, J Zipfel, E Takazawa

    EARTH AND PLANETARY SCIENCE LETTERS   172 ( 1-2 )   65 - 81   1999.10

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    The concentrations of the platinum-group elements (PGE) Ir, Ru, Pt and Pd were determined in 11 abyssal peridotites from ODP Sites 895 and 920, as well in six ultramafic rocks from the Horoman peridotite body, Japan, which is generally thought to represent former asthenospheric mantle. Individual oceanic peridotites from ODP drill cores are characterized by variable absolute and relative PGE abundances, but the average PGE concentrations of both ODP suites are very similar. This indicates that the distribution of the noble metals in the mantle is characterized by small-scale heterogeneity and large-scale homogeneity. The mean Ru/Ir and Pt/Ir ratios of all ODP peridotites are within 15% and 3%, respectively, of CI-chondritic values. These results are consistent with models that advocate that a late veneer of chondritic material provided the present PGE budget of the silicate Earth. The data are not reconcilable with the addition of a significant amount of differentiated outer core material to the upper mantle. Furthermore, the results of petrogenetic model calculations indicate that the addition of sulfides derived from percolating magmas may be responsible for the variable and generally suprachondritic Pd/Ir ratios observed in abyssal peridotites. Ultramafic rocks from the Horoman peridotite have PGE signatures distinct from abyssal peridotites: Pt/Ir and Pd/Ir are correlated with lithophile element concentrations such that the most fertile Iherzolites are characterized by non-primitive PGE ratios. This indicates that processes more complex than simple in-situ melt extraction are required to produce the geochemical systematics, if the Horoman peridotite formed from asthenospheric mantle with chondritic relative PGE abundances. In this case, the PGE results can be explained by melt depletion accompanied or followed by mixing of depleted residues with sulfides, with or without the addition of basaltic melt. (C) 1999 Elsevier Science B.V. All rights reserved.

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  • Polybaric petrogenesis of mafic layers in the Horoman peridotite complex, Japan Reviewed

    E. Takazawa, F. A. Frey, N. Shimizu, A. Saal, M. Obata

    Journal of Petrology   40 ( 12 )   1827 - 1851   1999

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    Two major types of mafic granulite layers occur within the Horoman peridotite, an 8 km x 10 km x 3 km orogenic lherzolite exposed in the high-T and low-P Hidaka metamorphic belt of Hokkaido, Japan. The mineral assemblages and textures of these layers reflect subsolidus reactions occurring during uplift from the upper mantle to the crust. Nevertheless, their whole-rock compositions can be used to infer the primary mineralogy of these layers, and a genetic relationship to melts geochemically similar to mid-ocean ridge basalts (MORB). The intralayer compositional variation of Type I layers (Al-Ti augite type mafic granulites) shows that the centers formed as garnet clinopyroxenites in equilibrium with an incompatible element depleted melt that crystallized to form the margins. In contrast, the Type II layers (Cr-diopside type mafic granulites) formed at relatively shallow depths and are much older, ~830 Ma, than the Type I garnet pyroxenites, which formed at ~80 Ma. The temporal sequence supports the hypothesis that the Horoman peridotite represents shallow MORB-related oceanic mantle that had subsided to deeper mantle depths before crustal emplacement.

    DOI: 10.1093/petroj/40.12.1827

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  • Petrogenesis of mafic layers in the Horoman peridotite complex, Japan

    Takazawa, E., Frey, F.A., Shimizu, N., Saal, A., Obata, M.

    Ofioliti   24 ( 1 A )   173 - 173   1999

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  • Abundances of trace elements in clinopyroxenes from the Horoman peridotite complex: Evidence of reaction with exotic melt/fluid

    Takazawa, E., Frey, F.A., Shimizu, N.

    Ofioliti   24 ( 1 A )   1999

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  • Re-Os isotopic composition of Horoman peridotite: Implications for the genesis of the plagioclase-lherzolite and the layered structure

    Saal, A., Takazawa, E., Frey, F.A., Shimizu, N., Hart, S.

    Ofioliti   24 ( 1 A )   160 - 160   1999

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  • Collapsing carbon nanotubes and diamond formation under shock waves Reviewed

    Y. Q. Zhu, T. Sekine, T. Kobayashi, E. Takazawa, M. Terrones, H. Terrones

    Chemical Physics Letters   287 ( 5-6 )   689 - 693   1998.5

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    In order to investigate the mechanical properties of carbon nanotubes, dynamic shock wave pressures (≤50 GPa) were applied on arc-discharge-generated carbon nanotubes containing polyhedral nanoparticles. High-resolution transmission electron microscopy (HRTEM) studies of the shock-recovered samples reveal that: (i) layers of the outer shells of the nanotubes break and transform into curled graphitic structures and (ii) the inner tube walls and bulk material display structural defects. Further X-ray powder diffraction and HRTEM analyses exhibit the presence of diamond nanocrystals which are produced after the shock-wave compression of polyhedral particles (present in the starting material).

    DOI: 10.1016/S0009-2614(98)00226-7

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  • Radiation temperatures of soda-lime glass in its shock-compressed liquid state Reviewed

    T. Kobayashi, T. Sekine, O. V. Fat'yanov, E. Takazawa, Q. Y. Zhu

    Journal of Applied Physics   83 ( 3 )   1711 - 1716   1998.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Institute of Physics Inc.  

    A radiation pyrometer in conjunction with a two-stage light gas gun has been used to measure shock temperatures of soda-lime glass in the pressure range 54-109 GPa. This pyrometer consists of two parts, i.e., an optical multichannel analyzer which measures the radiation spectrum over the visible range (∼450 nm window) and a four-channel photomultiplier tube system which records the time-varying behavior of shock temperatures. The measured radiation spectra are compared with the Planck function to estimate the shock temperatures and emissivities. Obtained spectra are well fit by the Planck function with moderate emissivities, indicating that relatively homogeneous thermal radiation is the main component of radiation. Obtained shock temperatures range from 2800 (100) to 5700 (300) K and they seem to represent shock temperatures of liquefied soda-lime glass (melt). The Hugoniot is well described by a linear relation, us = 0.14(21) + 1.92(5)up km/s. It is deduced that the radiation from liquids under shock compression, in contrast to the radiation from solids under shock compression, is more thermal and fits the Planck function well, even at lower temperatures. This is because the radiation spectrum of solids under compression often shows nonthermal radiation due to heterogeneous deformation, while the radiation spectrum of liquids under compression could not have such a nonthermal component. © 1995 American Institute of Physics.

    DOI: 10.1063/1.366889

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  • Shock-induced phase transitions among SiC polytypes Reviewed

    Y. Q. Zhu, T. Sekine, T. Kobayashi, E. Takazawa

    Journal of Materials Science   33 ( 24 )   5883 - 5890   1998

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Netherlands  

    A series of recovery experiments was conducted using a propellant single-stage gun on starting materials of both α-SiC and β-S\\C. X-ray examination on the recovered samples indicated that obvious polytype transformations among 3C, 6H, and 15R took place. To the α-SiC starting material, 15R tends to increase and 6H tends to decrease, while a small amount of α-SiC form transforms to 3C type, along with increasing the shock temperature and pressure. X-ray diffraction analysis showed that the β-SiC polytype is transformed into rhombohedral forms. From results of both types of SiC samples, rhombohedral polytypes seem to be the favored shock modification. The effects of shock pressure and shock temperature and their heterogeneous distribution on these polytype transitions are discussed in detail. Analysis showed that these polytype transitions resulted from the stacking sequence changes of SiC atom layers. © 1998 Kluwer Academic Publishers.

    DOI: 10.1023/A:1004482922441

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  • Hugoniot equation of state and high-pressure transformation of jadeite

    Takazawa, E., Sekine, T., Kobayashi, T., Zhu, Y.

    Journal of Geophysical Research: Solid Earth   103 ( 6 )   1998

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  • Evolution of the Horoman Peridotite (Hokkaido, Japan): Implications from pyroxene compositions Reviewed

    E Takazawa, F Frey, N Shimizu, M Obata

    CHEMICAL GEOLOGY   134 ( 1-3 )   3 - 26   1996.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Processes occurring in the Earth's upper mantle are important in controlling evolution of the crust-mantle system. The effects of multiple igneous and metamorphic processes are recorded in upper-mantle peridotites, such as the Horoman Peridotite in Hokkaido, Japan. Geochemical studies of these peridotites and their minerals, combined with determination of the spatial geochemical variations, can be used to understand the sequence of processes that affected the peridotite. In this study we show that compositional zoning patterns of major and trace elements in clinopyroxene porphyroclasts reflect a sub-solidus, closed-system transition from garnet peridotite, equilibrated at 20-24 kbar and 1040-1160 degrees C, to plagioclase peridotite equilibrated at similar to 7 kbar and 850-950 degrees C. The preservation of compositionally zoned pyroxenes indicates that this transition was a relatively recent process that probably occurred as the Horoman Peridotite was emplaced into the Hidaka metamorphic belt, The clinopyroxene compositions also show that: (I) harzburgites and lherzolites reacted with a fluid/melt that resulted in relative enrichment of highly incompatible elements, such as the light rare-earth elements; and (2) this enrichment process preceded the sub-solidus breakdown of garnet.

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  • Magma transport and metasomatism in the mantle: A critical review of current geochemical models - Discussion

    Navon, O., Frey, F.A., Takazawa, E.

    American Mineralogist   81 ( 5-6 )   1996

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.2138/am-1996-5-622

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  • GEOCHEMICAL EVIDENCE FOR MELT MIGRATION AND REACTION IN THE UPPER MANTLE Reviewed

    E TAKAZAWA, FA FREY, N SHIMIZU, M OBATA, JL BODINIER

    NATURE   359 ( 6390 )   55 - 58   1992.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    THE segregation of melts from the Earth's upper mantle into the crust is an important process in the chemical evolution of the crust-mantle system. The processes of melt formation and migration in the upper mantle are inadequately understood, but some important characteristics of these processes can be inferred from upper-mantle rocks exposed at the Earth's surface. The Horoman peridotite body in northern Japan is a layered upper-mantle rock. The major-element compositions of the layers are consistent with their formation as residues from varying extents of melting; however, abundances of rare-earth elements (REE) require additional processes to have occurred1, such as post-melting enrichment (metasomatism) resulting from reaction with a migrating fluid phase. We report here that chondrite-normalized REE patterns in clinopyroxenes show abrupt changes in slope, which vary with stratigraphic position and rock type. These data can be modelled by chromatographic fractionation as melts migrated through and interacted with peridotite, creating compositional heterogeneities in the upper mantle. In the Horoman peridotite these heterogeneities occur on a scale length of tens of metres.

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  • Compositional Variations within the Lower Layered Zone of the Horoman Peridotite, Hokkaido, Japan: Constraints on Models for Melt-Solid Segregation Reviewed

    Fred A. Frey, N. Shimizu, A. Leinbach, M. Obata, E. Takazawa

    JOURNAL OF PETROLOGY   211 - 227   1991

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:OXFORD UNIV PRESS  

    The lower zone, similar to 2 km in thickness, of the similar to 8 km x 10 km Horoman peridotite is layered with several repetitive sequences of harzburgite-lherzolite-plagioclase lherzolite. Major and trace element abundances were determined in seven whole rocks and their minerals from a 200-m section that ranges from plagioclase lherzolite to harzburgite. The clinopyroxene- and plagioclase-rich (similar to 15-20%) lherzolites contain similar to 3-5-4% Al2O3, similar to 3-3-5% CaO, olivines of similar to Fo(89), and they have a relative light REE depletion, [(LREE)(N) similar to 06 and (HREE)(N) similar to 2 (N = chondrite-normalized)]. The variations in bulk-rock major element content and mineral composition from plagioclase lherzolite to harzburgite are consistent with control by melt-solid segregation. For example, a simple model of mixing between harzburgite, residual from partial melting, and a melt can explain most of the whole-rock compositional variations; i.e., abundances of major elements, compatible trace elements, and some incompatible trace elements. However, the whole-rock harzburgites and their constituent clinopyroxenes have anomalously high LREE/HREE ratios. These data require a more complex mantle process such as relative LREE enrichment caused by metasomatizing fluids. Evidence for a metasomatic process is the common occurrence of secondary phlogopite in some harzburgite layers (Arai & Takahashi, 1989).

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  • Manganese nodules from the Upper Cretaceous Yubetsu Group, eastern Hokkaido, Japan Reviewed

    Masayuki SAKAKIBARA, Kiyoaki NIIDA, Kenji TOGARI, Masahide AKASAKA, Eiichi TAKASAWA, Yoshihiko GOTO, Masako YOSHIKAWA, Gaku KIMURA, Norio KITO, Jun TAJIKA, Takayuki KATO, Hideaki TODA

    Jour. Geol. Soc. Japan.   95 ( 3 )   241 - 244   1989

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    Language:Japanese   Publisher:The Geological Society of Japan  

    DOI: 10.5575/geosoc.95.241

    CiNii Article

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    Other Link: https://jlc.jst.go.jp/DN/JALC/00224918327?from=CiNii

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Books

  • マフィック岩を包有する不均質なマントルの部分融解に関する地質学的検証

    高澤, 栄一

    [高澤栄一]  2006 

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    Total pages:94p  

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MISC

  • Oman Drilling Project Phase1のリストヴェナイト中のドロマイト脈に薄い塩水からなる流体包有物があるぜよ

    川本竜彦, 佐藤宏樹, 高橋藤馬, GUOTANA Juan Miguel, 森下知晃, KELEMEN Peter B, COGGON Jude Ann, HARRIS Michelle, MATTER Juerg Michael, 道林克禎, 高澤栄一, TEAGLE Damon A H

    日本地球惑星科学連合大会予稿集(Web)   2019   2019

  • オマーンオフィオライトWadi Tayin岩体における地殻-マントル境界の岩石学および地球化学的特徴

    高澤栄一, 高澤栄一, 木暮優芽斗, CHATTERJEE Sayantani, 小柳夏希, 道林克禎, 田村芳彦

    日本地質学会学術大会講演要旨   126th   2019

  • Mantle-melt interaction at the crust-mantle boundary in the Wadi Tayin massif, the Oman mantle peridotite

    高澤栄一, 高澤栄一, 木暮優芽斗, 石井慶佑, CHATTERJEE Sayantani, 小柳夏希, 道林克禎, 田村芳彦

    日本鉱物科学会年会講演要旨(Web)   2019   2019

  • モホのつくり方

    田村芳彦, 高澤栄一, 高澤栄一, CEULENEER Georges, 道林克禎, 佐藤智紀, 小平秀一, 三浦誠一

    日本地球惑星科学連合大会予稿集(Web)   2018   2018

  • オマーン陸上掘削第1期ChikyuOman2017におけるオフィオライト地殻セクションの岩石物性研究速報

    阿部なつ江, 岡崎啓史, 畠山航平, ILDEFONSE Benoit, LEONG James Andrew, 立石大和, 道林克禎, 高澤栄一, KELEMEN Peter, TEAGLE Damon A H, HARRIS Michelle, COGGON Jude Ann, DE OBESO Juan Calros, MATTER Juerg

    日本地球惑星科学連合大会予稿集(Web)   2018   2018

  • オマーン陸上掘削第1期ChikyuOman2017における岩石物性研究速報

    阿部なつ江, 岡崎啓史, 畠山航平, ILDEFONSE Benoit, 立石大和, LEONG James Andrew, 道林克禎, 高澤栄一, KELEMEN Peter, TEAGLE Damon, HARRIS Michelle

    ブルーアースサイエンス・テク要旨集   2018   2018

  • モホ反射面のつくりかた

    田村芳彦, 藤江剛, 大平茜, 高澤栄一, CEULENEER Georges, 道林克禎, 佐藤智紀, 小平秀一, 三浦誠一

    日本地質学会学術大会講演要旨   125th   2018

  • Physical property measurement of ICDP Oman Drilling Project (ChikyuOman2017) Phase I-From Oceanic Plate to obduction stage

    阿部なつ江, 岡崎啓史, 畠山航平, ILDEFONSE Benoit, 立石大和, LEONG James Andrew, 道林克禎, 高澤栄一, KELEMEN Peter, DE OBESO Juan Calros, TEAGLE Damon, COGGON Jude, HARRIS Michelle

    日本鉱物科学会年会講演要旨(Web)   2018   2018

  • オマーンオフィオライト南部でのハンレイ岩-カンラン岩関係

    森下知晃, 荒井章司, KELEMEN Peter, TEAGLE Damon, 石井慶佑, 高澤栄一, NGUYEN Khac Du, COGGON Jude, MATTER Juerg, 道林克禎, 田村芳彦, MOE KhawThu, 山田泰広

    日本地質学会学術大会講演要旨   125th   2018

  • オマーン掘削プロジェクト速報:海洋プレート層序のXCTプロファイル

    道林克禎, 高澤栄一, KELEMEN Peter, TEAGLE Damon, HARRIS Michelle, GODARD Marguerite

    日本地質学会学術大会講演要旨   125th   2018

  • ICDPオマーン陸上掘削コア試料に記録されているモホ遷移帯の岩石物性について

    阿部なつ江, MOE Kyaw, 山田泰広, 岡崎啓史, 畠山航平, 赤松祐哉, 片山郁夫, 高澤栄一, 道林克禎, KELEMEN Peter, TEAGLE Damon

    日本地質学会学術大会講演要旨   125th   2018

  • ICDP Oman Drilling Project:オマーンオフィオライトWadi Tayin岩体における地殻-マントル境界の掘削

    高澤栄一, COGGON Jude, KELEMEN Peter, MATTER Juerg, 道林克禎, 森下知晃, 田村芳彦, TEAGLE Damon, KHAW Thu Moe, 山田泰広

    日本地質学会学術大会講演要旨   125th   2018

  • 国際陸上掘削計画による沈み込むプレート境界相当岩石コア(オマーンオフィオライト基底部Listvenite/変成岩境界)の海洋掘削船CHIKYUを用いた記載とその成果

    森下知晃, KELEMEN B. Peter, COGGON Judith, MATTER Juerg, HARRIS Michelle, 道林克禎, 高澤栄一, TEAGLE A.H. Damon, GODARD Marguerite

    日本鉱物科学会年会講演要旨(Web)   2018   2018

  • オマーンオフィオライト・ワディタイン岩体CMサイトにおける地殻-マントル遷移帯の陸上掘削

    高澤栄一, COGGON Jude Ann, KELEMEN Peter B, MATTER Juerg Michael, 道林克禎, 田村芳彦, TEAGLE Damon A H, KHAWTHU Moe, 山田泰広

    日本地球惑星科学連合大会予稿集(Web)   2018   2018

  • マントルウエッジプレート境界掘削:オマーン陸上掘削-サマイル・オフィオライトの炭酸塩岩化したカンラン岩から下位の変成岩までの掘削成果概要

    森下知晃, KELEMEN Peter B, COGGON Judith, MATTER Juerg, HARRIS Michelle, 道林克禎, 高澤栄一, TEAGLE Damon A H, GODARD Marguerti

    日本地球惑星科学連合大会予稿集(Web)   2018   2018

  • 海洋底下部地殻ハンレイ岩相の白金族元素存在度とOs同位体組成:ICDP Oman Drilling Project phase1速報

    仙田量子, 鈴木勝彦, 森下知晃, KELEMEN Peter, TEAGLE Damon, 高澤栄一, COGGON Jude, MATTER M. Juerg, HARRIS Michelle, 道林克禎

    日本地球化学会年会要旨集(Web)   65th   2018

  • マントル掘削計画~海と陸とちきゅうと~

    道林克禎, 高澤栄一, 田村芳彦, 小原泰彦, 岡本敦, 森下知晃, 石塚治, 針金由美子, 藤江剛, 片山郁夫, 渡邊了

    ブルーアース要旨集   2017   2017

  • Report of the 2nd International Symposium on Earth History of Asia, 31 October – 3 November, 2014, Niigata, Japan

    Science reports of Niigata University. (Geology)   30   89 - 96   2015.3

  • Protolith of metamorphic sole in the Oman ophiolite inferred from whole rock trace element abundances and Sr-Nd isotope ratios

    Takazawa Eiichi, Mori Namiko, Nohara Rikako, Takahashi Toshiro, Adachi Yoshiko, Miyashita Sumio

    Science reports of Niigata University. (Geology)   29   48 - 49   2014.10

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  • モホ点描―超深部掘削で何がわかるのか?オマーンオフィオライト・サラヒ岩体マントルセクションの鉱物組成分布からみた海嶺‐島弧変遷プロセス

    高澤栄一, 春日良一, 山野井陽一

    月刊地球   34 ( 4 )   252 - 257   2012.4

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  • モホ点描―超深部掘削で何がわかるのか?オマーンオフィオライト・フィズ岩体のマントルセクションに分布するダナイトの空間的な組成変動と成因について

    末武杏奈, 高澤栄一

    月刊地球   34 ( 4 )   247 - 251   2012.4

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  • The MoHole: A Crustal Journey and Mantle Quest Workshop Report

    ILDEFONSE Benoît, ABE Natsue, BLACKMAN Donna K, CANALES J. Pablo, ISOZAKI Yoshio, KODAIRA Shuichi, MYERS Greg, NAKAMURA Kentaro, NEDIMOVIC Mladen, SKINNER Alesander, SEAMA Nobukazu, TAKAZAWA Eiichi, TEAGLE Damon A.H, TOMINAGA Masako, UMINO Susumu, WILSON Douglas S, YAMAO Masaoki

    Workshop Report   1-67   2010.6

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  • Ridge segmentation and compositional variation in the mantle section of the Fizh Block, the Oman ophiolite

    Chikyu monthly   30 ( 2 )   86 - 93   2008.4

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  • Hybridization of dunite and gabbroic materials in Hole 1271B from Mid-Atlantic Ridge 15°N : Implications for melt flow and reaction in the upper mantle

    TAKAZAWA E.

    Proceedings of the Ocean Drilling Program. Scientific Reports, College Station, TX (Ocean Drilling Program), 2007   209   1 - 23   2007

  • Spatial variation of trace element abundances in clinopyroxenes from the layered orogenic lherzolite (Horoman peridotite, Japan): Implications for melt flow and reaction in the upper mantle

    E Takazawa, FA Frey, N Shimizu, M Obata, JL Bodinier

    GEOCHIMICA ET COSMOCHIMICA ACTA   67 ( 18 )   A471 - A471   2003.9

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    Language:English   Publishing type:Research paper, summary (international conference)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

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  • マントル内の延性せん断帯の空間分布から読みとる海洋プレートの断片化過程 北部オマーンオフィオライトの例

    道林克禎, 高沢栄一, 岡安冬恵

    日本地質学会学術大会講演要旨   108th   2001

  • Whole-rock compositional variations in an upper mantle peridotite (Horoman, Hokkaido, Japan) : implications for melt segregation, migration and reaction.

    TAKAZAWA E.

    Geochim. Cosmosim. Act.   64   717 - 732   2000

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Presentations

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Awards

  • Paper Award

    2021.9   Japan Association of Mineralogical Sciences   Yao, Y., Takazawa, E., Chatterjee, S., Richard, A., Morlot, C., Créon, L., Al–Busaidi, S., Michibayashi, K., Oman Drilling Project Science Team (2020) High resolution X–ray computed tomography and scanning electron microscopy studies of multiphase solid inclusions in Oman podiform chromitite: implications for post–entrapment modification. Journal of Mineralogical and Petrological Sciences, 115, 247–260.

    Eiichi Takazawa, Katsuyoshi Michibayashi

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Research Projects

  • Clarification of alteration of the upper mantle in the mid-ocean ridge and subduction zone

    Grant number:20H02005

    2020.4 - 2025.3

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

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

    Awarding organization:Japan Society for the Promotion of Science

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    Authorship:Principal investigator 

    Grant amount:\17550000 ( Direct Cost: \13500000 、 Indirect Cost:\4050000 )

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  • Physical properties of uppermost mantle structure and the Mohorovicic seismic discontinuity

    Grant number:16H06347

    2016.5 - 2021.3

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

    Research category:Grant-in-Aid for Scientific Research (S)

    Awarding organization:Japan Society for the Promotion of Science

    Michibayashi Katsuyoshi

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    Grant amount:\184210000 ( Direct Cost: \141700000 、 Indirect Cost:\42510000 )

    In order to clarify the structure of the uppermost mantle and the formation process of the Mohorovicic discontinuity (Moho), which is the crust-mantle boundary, this study was carried out using a multifaceted approach, including microstructural analysis, measurements of physical properties, and rock-water reaction experiments, mainly on marine and terrestrial peridotites. We confirmed that the microstructure of peridotite at depths of 6,000 m or more in the Ogasawara Trench has been affected by water, and elucidated the new dynamics of deep fluids involved in rock-water reactions. We drilled the Oman ophiolite body in the Arabian Peninsula and successfully recovered continuous samples of crustal to mantle materials, and their analyses provided numerous insights for quantitative understanding of rock-fluid reaction processes in oceanic plates. Based on these results, we have developed a new model for the formation of the Moho surface and a model for the uppermost mantle structure.

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  • Elucidations of the physical properties and actual condition of the crust-mantle boundary (Moho) by onshore drilling of the Oman Ophiolite

    Grant number:16H02742

    2016.4 - 2020.3

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

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

    Awarding organization:Japan Society for the Promotion of Science

    TAKAZAWA Eiichi

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\45110000 ( Direct Cost: \34700000 、 Indirect Cost:\10410000 )

    We participated in the International Continental Scientific Drilling Program (ICDP) Oman drilling project and carried out onshore drilling of the crust-mantle boundary in the Oman ophiolite. In the Holes CM1A and CM2B of Wadi Tayin massif, we succeeded in completely collecting the drilling core with a recovery rate of 100%. As a result of drilling, it was revealed that there is a 150m thick lithology mainly composed of dunite at the boundary between the crust and the mantle. From the depth variation of whole rock and mineral science composition, it was found that the process of formation of dunite by the reaction of harzburgite and basaltic melt is recorded. Moreover, from the physical analysis of the core, the seismic velocity of the mantle that has undergone serpentinization is much lower than that of the lower crust.

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  • Redox state of mantle wedge inferred from the mantle section of the Oman ophiolite

    Grant number:26610173

    2014.4 - 2017.3

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

    Research category:Grant-in-Aid for Challenging Exploratory Research

    Awarding organization:Japan Society for the Promotion of Science

    Takazawa Eiichi, SATISH-KUMAR M, AKASAKA Masahide

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\3770000 ( Direct Cost: \2900000 、 Indirect Cost:\870000 )

    We studied the spatial distribution of oxygen fugacity in the Fizh mantle section of the northern Oman ophiolite as an analog for the redox state of mantle wedge. The delta log fO2 relative to FMQ buffer of harzburgites and dunites were calculated following the method of Ballhaus et al. (1991). The values range from FMQ-3.3 to +1.8 and tend to decrease from the crust-mantle boundary (Moho) to the basal part of the mantle section. Dunites are more oxidized than harzburgites. The Fe3+/∑Fe ratio of spinel were evaluated by Mossbauer spectroscopy. The difference is negligible compared to the whole range. The V/Sc and Zn/Fe ratios of whole rock peridotites show a strong negative and positive correlations with delta log fO2 (FMQ), respectively, indicating the observed variation and tendency of delta log fO2 (FMQ) are consistent with residues formed by flux melting of mantle section with a reduced melt/fluid derived from subducted sediment.

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  • 初期島弧における海洋リソスフェアの再融解とボニナイトの生成に関する地質学的検証

    2007.4 - 2010.3

    System name:科学研究費 基盤研究 (C)

    Awarding organization:日本学術振興会

    高澤 栄一

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\4550000 ( Direct Cost: \3500000 、 Indirect Cost:\1050000 )

    オマーンオフィオライト北部に位置するフィズ岩体マントルセクションに分布するかんらん岩類と貫入岩類の構造と化学組成を分析し、中央海嶺における海洋リソスフェアの形成から海洋デタッチメントによる初期島弧での改変のプロセスを明らかにした。とくに融け残りかんらん岩の組成分布から海嶺セグメント構造が見いだされた。海嶺セグメント境界には高枯渇のハルツバージャイトとダナイトが分布し,海洋リソスフェアのデタッチメントに伴い,多量の流体が流動したことが明らかになった。

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  • Comparative study of oceanic plate and ophiolite based on accurate analyses of crustal and mantle material

    Grant number:17340162

    2005 - 2007

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

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

    Awarding organization:Japan Society for the Promotion of Science

    MIYASHITA Sumio, TAKAZAWA Eiichi, MAEDA Jin-ichiro

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    Grant amount:\15700000 ( Direct Cost: \14800000 、 Indirect Cost:\900000 )

    The results obtained from this research project are summarized as follows.
    Systematic mineral and bulk rock analyses for mantle harzburgites sampled from extensive area of the northern Oman ophiolite indicate that a highly depleted zone is present within the mantle section. The depleted zone is defined by the appearance of Cr-spinels with high Cr# (Cr/(Cr+Al), and traced along the shear zone trending NW-SE described by French group. Remelting of mantle sections caused by invasion of fluids expelled from the underling basement during oceanic thrusting movement would bring a such depleted zone.
    We have examined a regional variation of the mantle-crust transition zone. Lithologic column obtained from7 routes, located at different locations in a segment architecture, indicate a systematic variation of the mantle-crust transition zone depending on the segment structure, as follows. The thickness of the transition zone thickens toward the segment center, and become to thin at the segment margin. However, abnormally thick transition zone was found from the northern tribute branch of Wadi Fizh, locating at the most margin of the segment. Systematic variations in structural features in the transition zone are also obvious, that is, intensive lineation and foliation are well observed at the segment center, while they are only poorly developed at the segment margin. These results suggest that mantle upwelling and magmatic flowage were more vigorous at the segment center. Also lithologic column for extrusive successions are studied at different localities in terms of segment structure. Systematic variations in respect to mode of occurrence of the extrusives were found, as follows: Massive flows are predominant at the segment center with numerous numbers of unit. Whereas, pillow lavas are predominant at the segment margin and are characterized by much thicker unit than the segment center. Thus, both extrusives in the uppermost level, and deeper section of the crust, were controlled by segmentation structure.

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  • Geological Study of Partial Melting of Mafic Rock-Bearing Heterogeneous Upper Mantle

    Grant number:16540413

    2004.4 - 2006.3

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

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

    Awarding organization:Japan Society for the Promotion of Science

    TAKAZAWA Eiichi

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\3400000 ( Direct Cost: \3400000 )

    This research investigated the partial melting and mantle-melt reaction occurred in the Horoman peridotite on the basis of field occurrence and major and trace element abudances in mafic rocks. As a result of study, Type I mafic granulite of the Horoman peridotite were experienced remelting event about 80 million years ago. The center of the mafic layer may have been garnet clinopyroxenite while the margin was a primitive melt in equilibrium with the center in terms of trace elements. Both are now metamorphosed into mafic granulite during uplifting of the Horoman peridotite.
    Following this study, I investigated the mantle section of the Oman ophiolite in 2004-2005 to understand formation of chemical heterogeneity by partial melting of oceanic upper mantle. Detailed analysis of mineral compositions of peridotite samples revealed the presence of highly refractory peridotite zone that obliquely crosscuts the mantle section parallel to the low temperature shear zone. It is advocated that the refractory zone formed by remelting of harzburgite due to reduction of solidus temperature as a result of fluid flow along shear zone.
    Third, heterogeneity of oceanic upper mantle was directly examined using peridotite samples drilled at Mid-Atlantic Ridge in 14°N〜16°N during ODP Leg 209. Optical investigation under microscope and analysis of mineral compositions for drilled cores from Hole B, Site 1271showed that melt flow and mantle-melt reaction in shallowest upper mantle produced a series of lithologies such as impregnated dunite, olivine gabbro, gabbronorite and troctolite as hybrid rocks between dunite and mafic melt.

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  • Geological Study of Partial Melting of Mafic Rock-Bearing Heterogeneous Upper Mantle

    Grant number:16540413

    2004 - 2005

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

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

    Awarding organization:Japan Society for the Promotion of Science

    TAKAZAWA Eiichi

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    Grant amount:\3400000 ( Direct Cost: \3400000 )

    This research investigated the partial melting and mantle-melt reaction occurred in the Horoman peridotite on the basis of field occurrence and major and trace element abudances in mafic rocks. As a result of study, Type I mafic granulite of the Horoman peridotite were experienced remelting event about 80 million years ago. The center of the mafic layer may have been garnet clinopyroxenite while the margin was a primitive melt in equilibrium with the center in terms of trace elements. Both are now metamorphosed into mafic granulite during uplifting of the Horoman peridotite.
    Following this study, I investigated the mantle section of the Oman ophiolite in 2004-2005 to understand formation of chemical heterogeneity by partial melting of oceanic upper mantle. Detailed analysis of mineral compositions of peridotite samples revealed the presence of highly refractory peridotite zone that obliquely crosscuts the mantle section parallel to the low temperature shear zone. It is advocated that the refractory zone formed by remelting of harzburgite due to reduction of solidus temperature as a result of fluid flow along shear zone.
    Third, heterogeneity of oceanic upper mantle was directly examined using peridotite samples drilled at Mid-Atlantic Ridge in 14°N〜16°N during ODP Leg 209. Optical investigation under microscope and analysis of mineral compositions for drilled cores from Hole B, Site 1271showed that melt flow and mantle-melt reaction in shallowest upper mantle produced a series of lithologies such as impregnated dunite, olivine gabbro, gabbronorite and troctolite as hybrid rocks between dunite and mafic melt.

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  • Geological study of interaction between lithospheric mantle and asthenosphere

    Grant number:14540421

    2003.4 - 2005.3

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

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

    Awarding organization:Japan Society for the Promotion of Science

    TAKAZAWA Eiichi

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\4100000 ( Direct Cost: \4100000 )

    This research investigated the mantle-melt reaction that occurs at Earth's extensional environments such as continental rift and mid-ocean ridge. The studied fields includes the Horoman peridotite complex in the Hidaka Metamorphic Belt, Hokkaido, Japan and the mantle section of the Oman ophiolite. On the basis of spatial variation of trace elements such as rare earth elements in the mantle peridotites and in their constituent minerals the reaction between lithospheric mantle and ascending asthenospheric melt was quantitatively modeled. The study showed that the Horoman peridotite are highly heterogeneous in a meter scale so that even in the 140 meters section fertile Iherzolite with primitive mantle composition and depleted harzburgite are observed. The variation of incompatible elements are further complicated thereby showing the metasomatism by asthenospheric melt flow. On the other hand, the mantle section of the Oman ophiolite are more homogeneous in the scale of ten kilo meters. Abundances of major and trace element in the area of 25 x 15km^2 in the Oman mantle section are less variable than those in the 140m section of the Horoman peridotite. Compositional variations in the mantle section of the Oman ophiolite are mainly explained by partial melting and melt extraction beneath mid-ocean ridge. However, this research found greater variations in the Oman ophiolite than it has been known before. These heterogeneities may have formed by remelting and refertilization of oceanic lithospheric mantle in a scale of km.

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  • Geological study of interaction between lithospheric mantle and asthenosphere

    Grant number:14540421

    2002 - 2003

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

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

    Awarding organization:Japan Society for the Promotion of Science

    TAKAZAWA Eiichi

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    Grant amount:\4100000 ( Direct Cost: \4100000 )

    This research investigated the mantle-melt reaction that occurs at Earth's extensional environments such as continental rift and mid-ocean ridge. The studied fields includes the Horoman peridotite complex in the Hidaka Metamorphic Belt, Hokkaido, Japan and the mantle section of the Oman ophiolite. On the basis of spatial variation of trace elements such as rare earth elements in the mantle peridotites and in their constituent minerals the reaction between lithospheric mantle and ascending asthenospheric melt was quantitatively modeled. The study showed that the Horoman peridotite are highly heterogeneous in a meter scale so that even in the 140 meters section fertile Iherzolite with primitive mantle composition and depleted harzburgite are observed. The variation of incompatible elements are further complicated thereby showing the metasomatism by asthenospheric melt flow. On the other hand, the mantle section of the Oman ophiolite are more homogeneous in the scale of ten kilo meters. Abundances of major and trace element in the area of 25 x 15km^2 in the Oman mantle section are less variable than those in the 140m section of the Horoman peridotite. Compositional variations in the mantle section of the Oman ophiolite are mainly explained by partial melting and melt extraction beneath mid-ocean ridge. However, this research found greater variations in the Oman ophiolite than it has been known before. These heterogeneities may have formed by remelting and refertilization of oceanic lithospheric mantle in a scale of km.

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  • かんらん岩からマントルプロセスを読む-新たな展開と第4回国際レルゾライト会議をめざして

    Grant number:13894015

    2001

    System name:科学研究費助成事業 基盤研究(C)

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    小畑 正明, 小澤 一仁, 新井田 清信, 荒井 章司, 高橋 奈津子, 高澤 栄一

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    Grant amount:\3400000 ( Direct Cost: \3400000 )

    2001年7月21日から25日にわたって,北海道様似町の様似町公民館及びアポイ山荘会議室にてシンポジウム「かんらん岩とマントルプロセス」を開催した.本集会は2002年8-9月北海道様似町で開催予定の第4回国際ワークショップ「造山帯レルゾライトとマントルプロセス」に向けて国内の準備体制を強化し,国内の研究をより一層推進するためのものであった.21日,22日及び23日の夜間は室内講演会,討論会を行った.また23日,24日は幌満かんらん岩の野外地質巡検を実施した.全国の大学から教官21名,学生,院生11名の計32名が参加し,室内討論会では19編の口頭発表と7編のポスターの発表がなされた.カバーしたテーマは岩石学,構造地質学・実験岩石学・微量元素・同位体地球化学,地球物理学,など多方面にわたり,短期間であったが集中的な討議ができた.野外地質巡検では,2002年の本会議の時の巡検予定コースを実地に検討することで幌満かんらん岩の研究の最前線を野外で検証し知識を参加者間で共有する事ができた.25日は関係者で準備委員会を行い,様似町側と詳細な準備打ち合わせを行った.なお本シンポジウムで発表された講演の要旨は別に冊子にまとめ参加者,関係者に配布するべく3月現在準備中である.
    9月下旬には金沢において準備委員会を開催し,本会議のセカンドサーキュラーの骨子を作成,その後関係者間で協議を続けることにより,11月にセコンドサーキュラーを完成させweb上で公開するとともに,世界に配布した・またこの間海外の組織科学プログラムメンバーとも意見を交わし,会議のプロシーディングをJ.Petrolgyに出すこと,またそのゲストエディターのメンバーを決定し2002年の国際会議に向けて準備を大きく進めることができた.

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  • Generation and reorganization of Oman oceanic crust-mantle

    Grant number:11691121

    1999 - 2000

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

    Research category:Grant-in-Aid for Scientific Research (A).

    Awarding organization:Japan Society for the Promotion of Science

    ARAI Shoji, UMINO Susumu, TAKAZAWA Eiichi, MIYASHITA Sumio, MIZUTA Toshio, MASUDA Toshiaki

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    Grant amount:\20000000 ( Direct Cost: \20000000 )

    1. We recognized a wide petrographical variation of peridotite, its deformational history, cystallographical change of minerals and origin of mylonites within the upper mantle section of the northern Oman ophiolite. High-PGE chromitite was also discovered.
    2. We classified the late-intrusive rocks into three types in terms of petrography. Komatititic extrusives were found associated with picrite basalt, a quench phase of the late intrusives.
    3. The segmetation structure of a mid-ocean ridge was estimated by the strutural change of gabbroic layers. Noritic gabbro intruding around the derivative magma chmabers around the segment center impose contact metamorphism of up to granulite facies on surrounding sheeted dike complex. The structure and evolutional history of the roof zone of magma chambers were clarified.
    4. The upper lavas can be classified into three groups by high-accuracy chemical analysis of their Cpx phenocrysts, and the genesis was estimated for individual groups. Boninite was newly found. Preliminary data on the Salahi volcanics that erupted at the obuduction stage were presented.
    5. Hysrothermal metal mineralization was geologically and geochemically examined to understand its genesis. Reaction between aqueous fluid and chlorite in meta-basalts is of vital importance for their characteristics of Zn and Ni contents. The water/rock ratio in the hydrothermal fluid formation is around 20, that is far higher than the calculated values, 2 to 4.
    6. The thermal structure of the ocean-floor metamorphism was examined in basalt to dolerite to confirm a temprature increase downward.
    7. The shear sense on the metamorphic sole is NE-SW and the hanging side was confirmed to have moved toward SW.The basic amphibolite of the sole demonstrates variable flow textures within several tens of meters from the contact with overlying ultramafic rocks.

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  • PRIMARY FORMATION AGES AND CIRCUMUSTANCES OF PRECRETACEOUS ROCKS MAKING UP THE RYOKE BELT IN HONSHU ARC

    Grant number:10440139

    1998 - 2000

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

    Research category:Grant-in-Aid for Scientific Research (B).

    Awarding organization:Japan Society for the Promotion of Science

    KAGAMI Hiroo, SHIMURA Toshiaki, TAKASAWA Eiichi, KOBAYASHI Kenta, TAINOSHO Yoshiaki, TOYOSHIMA Tsuyoshi

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    Grant amount:\13000000 ( Direct Cost: \13000000 )

    Crustal evolution of the Ryoke Belt is as follows ; (1) 2000-1800Ma.Granitic upper crust was formed from depleted mantle-origin lower crust, which is a primitive basement of the Ryoke Belt. These age data were obtained from Nd model ages of sedimentary-origin metamorphic rocks and granites, which were calculated using depleted mantle parameters, and U-Pb zircons contained in Cretaceous Ryoke granites and Jurassic mafic rocks. (2) 1750-1600Ma. Ceologic events of this age range are not clear. These age data were obtained from Nd model calculations of sedimentary-origin metamorphic rocks and granites. (3)220-190Ma. Mafic volcanism and plutonism took place under continental circumustances. These magmas were derived from continental lithospheric mantle. Age data of this range were measured using Sm-Nd whole rock isochron and whole rock-mineral isochron of gabbros and metadiabases. (4) 170-160Ma. Some mafic to intermediate rocks were formed during this age range. Age data of this range were obtained from Sm-Nd and Rb-Sr whole rock isochrons and Sm-Nd whole rock-mineral isochron. (5) 125-70Ma. Voluminous felsic igneous activity took place during this age ranges under island arc and continental margin circumustances. These age data were obtained from Rb-Sr whole rock isochron. Sm-Nd and Rb-Sr whole rock-mineral isochronos. As initial Sr and Nd isotopic compositions of these rocks are the same as the 220-190Ma mafic rocks, the felsic magmas are considered to have derived from the continental lithosphere lower crust and upper mantle.
    The Cretaceous to Paleogene igneous rocks showing the same isotopic features with Ryoke felsic igneous rocks are widely distributed in the Honshu Arc, which means that the Ryoke-type continental lithosphere basically made up the Honshu Arc.

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  • Geodynamics of generation of oceanic crust-an example of the Oman ophiolite

    Grant number:09041101

    1997 - 1998

    System name:Grants-in-Aid for Scientific Research Grant-in-Aid for international Scientific Research

    Research category:Grant-in-Aid for international Scientific Research

    Awarding organization:Japan Society for the Promotion of Science

    MIYASHITA Sumio, TAKAZAWA Eiichi, ISHIKAWA Tsuyoshi, UMINO Susumu

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    Grant amount:\17700000 ( Direct Cost: \17700000 )

    The results obtained from this research project are summarized for each group.
    Mantle group clarified an interaction between melt and mantle in the mantle-crust transition zone. Also they round the interaction was quite hetrogenous palce to place. Analyses of spinel using river sand show that the mantle peridotites of the Oman ophiolite are highly depleted compared to oceanic mantle, suggesting that signiricant modification or the mantle peridotite occured during later island arc stage.
    Gabbro group round two series of gabbros previously regarded as successive complex, which were formed at advancing and dying magma chambers beneath ocean ridges, respectively. This is explained by overlapping ocean ridges where propagation and retreating or ridges appeared. The central part of ridge segment where thick Moho transition zone occurs was determined through regional detailed geological mapping in the northern Oman ophiolite. From the central part to the tip or ridge segmenl, mineral compositions or layered gabbro varies systematically from less evolved to more evolved compositions.
    Upper crust group measured direction and thickness of dikes from extensive area in the northern Oman ophiolite. They found that the direction of dikes varies for each several km length, indicating the smallest order of segmentation of ocean ridges. The thickness of dikes increases from the central part to tip of the ridge segment in more large scale which is presumed from the petrological features of gabbro and mantle peridotite.
    Structural group found two different mineral lineations on foliation plane in the metamorphic sole beneath the Oman ophiolite. Also they clarified that the degree of preferred orientation is quite various even in one outcrop.

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Teaching Experience

  • 海外フィールド体験実習

    2023
    Institution name:新潟大学

  • 海外フィールド科学実習B

    2023
    Institution name:新潟大学

  • 地球環境フィールド科学演習

    2023
    Institution name:新潟大学

  • フィールド産業インターンシップ

    2023
    Institution name:新潟大学

  • 地球環境科学特論

    2023
    Institution name:新潟大学

  • 海外フィールド科学実習A

    2023
    Institution name:新潟大学

  • 理学基礎演習

    2022
    Institution name:新潟大学

  • 基礎英語コミュニケーション

    2022
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2022
    Institution name:新潟大学

  • 実践英語コミュニケーション

    2022
    Institution name:新潟大学

  • 地球深部物質論

    2021
    Institution name:新潟大学

  • 台湾スプリングセミナー I

    2021
    Institution name:新潟大学

  • 台湾スプリングセミナー II

    2021
    Institution name:新潟大学

  • 地球科学特別講義I

    2021
    -
    2022
    Institution name:新潟大学

  • 野外実習I

    2021
    Institution name:新潟大学

  • 課題研究(地質科学)

    2020
    Institution name:新潟大学

  • 論文講読演習

    2020
    Institution name:新潟大学

  • 専門力アクティブ・ラーニング

    2020
    -
    2021
    Institution name:新潟大学

  • 先端科学技術総論

    2020
    Institution name:新潟大学

  • 自然科学総論Ⅴ

    2020
    Institution name:新潟大学

  • 地質調査法実習III

    2019
    Institution name:新潟大学

  • 岩石学C

    2019
    Institution name:新潟大学

  • 野外実習A

    2019
    Institution name:新潟大学

  • 野外実習B

    2019
    Institution name:新潟大学

  • 鉱物・岩石学入門

    2018
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2018
    -
    2022
    Institution name:新潟大学

  • 地質学入門a

    2017
    Institution name:新潟大学

  • 地学基礎実習a

    2017
    Institution name:新潟大学

  • フィールド体験実習

    2017
    Institution name:新潟大学

  • 総合力アクティブ・ラーニング

    2017
    Institution name:新潟大学

  • Earth Science todayⅡ

    2017
    Institution name:新潟大学

  • 地学基礎実習b

    2017
    Institution name:新潟大学

  • 岩石学実験II

    2016
    Institution name:新潟大学

  • 論文作成演習D

    2014
    Institution name:新潟大学

  • 地球科学特別講義III

    2014
    Institution name:新潟大学

  • 地球科学特定研究Db

    2014
    Institution name:新潟大学

  • 岩石学実験I

    2013
    Institution name:新潟大学

  • 台湾スプリングセミナー I

    2013
    -
    2018
    Institution name:新潟大学

  • 台湾スプリングセミナー II

    2013
    -
    2018
    Institution name:新潟大学

  • 地球科学特定研究Dc

    2013
    -
    2015
    Institution name:新潟大学

  • 学術発表演習D

    2013
    -
    2014
    Institution name:新潟大学

  • 中間発表D

    2013
    -
    2014
    Institution name:新潟大学

  • グローバルミーティング

    2013
    Institution name:新潟大学

  • プロジェクト研究特別概説

    2013
    Institution name:新潟大学

  • リサーチインターンシップ

    2013
    Institution name:新潟大学

  • 課題研究(地質科学科)

    2012
    -
    2016
    Institution name:新潟大学

  • 学術発表演習M

    2012
    -
    2015
    Institution name:新潟大学

  • 地球科学特定研究Ma

    2012
    -
    2015
    Institution name:新潟大学

  • 地球科学演習D

    2012
    -
    2015
    Institution name:新潟大学

  • 地球科学演習Ma

    2012
    -
    2015
    Institution name:新潟大学

  • 地球科学特定研究Mb

    2012
    -
    2014
    Institution name:新潟大学

  • 地球科学演習Mb

    2012
    -
    2014
    Institution name:新潟大学

  • 中間発表M

    2012
    -
    2014
    Institution name:新潟大学

  • 地球科学特定研究Da

    2012
    -
    2013
    Institution name:新潟大学

  • 海洋地質学

    2012
    -
    2013
    Institution name:新潟大学

  • リサーチキャンプ

    2012
    Institution name:新潟大学

  • 海洋地殻生成論

    2012
    Institution name:新潟大学

  • 論文作成演習M

    2012
    Institution name:新潟大学

  • 自然構造科学特定研究MⅠ

    2012
    Institution name:新潟大学

  • 自然構造科学演習MⅠ

    2012
    Institution name:新潟大学

  • 岩石学A

    2011
    Institution name:新潟大学

  • セミナー

    2010
    Institution name:新潟大学

  • 課題研究

    2010
    Institution name:新潟大学

  • 岩石学B

    2010
    Institution name:新潟大学

  • 地球物理学

    2008
    Institution name:新潟大学

  • 野外実習III

    2008
    -
    2018
    Institution name:新潟大学

  • 海底地質学

    2008
    -
    2010
    Institution name:新潟大学

  • 地質調査法II

    2007
    Institution name:新潟大学

  • 地質調査法I

    2007
    Institution name:新潟大学

  • 地質調査法実習II

    2007
    Institution name:新潟大学

  • 地質調査法実習I

    2007
    Institution name:新潟大学

  • マントル・地殻ダイナミクス

    2007
    Institution name:新潟大学

  • 地球化学分析法

    2007
    Institution name:新潟大学

  • 地学概論A

    2007
    Institution name:新潟大学

  • 野外実習I

    2007
    -
    2021
    Institution name:新潟大学

  • 地史学原理

    2007
    -
    2017
    Institution name:新潟大学

  • 地球深部物質論

    2007
    -
    2017
    Institution name:新潟大学

  • 野外実習II

    2007
    -
    2017
    Institution name:新潟大学

  • 地学実験C

    2007
    -
    2016
    Institution name:新潟大学

  • スタディ・スキルズ(地質科学学習法)

    2007
    -
    2016
    Institution name:新潟大学

  • 固体地球化学

    2007
    -
    2013
    Institution name:新潟大学

  • 鉱物学A

    2007
    -
    2012
    Institution name:新潟大学

  • 鉱物学B

    2007
    -
    2012
    Institution name:新潟大学

  • 生きている地球

    2007
    -
    2011
    Institution name:新潟大学

▶ display all