Researcher Database

Hisayoshi Yurimoto
Faculty of Science Earth and Planetary Sciences Earth and Planetary System Science
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science Earth and Planetary Sciences Earth and Planetary System Science

Job Title

    Professor

Degree

  • DSc, University of Tsukuba

URL

Research funding number

  • 80191485

Research Interests

  • SIMS   GeochemistryCosmochemistry   

Research Areas

  • Earth and planetary science / Geochemistry/Cosmochemistry
  • Earth and planetary science / Petrology/Mineralogy/Economic geology
  • Earth and planetary science / Geology
  • Applied physics / Applied optics/Quantum optical engineering
  • Earth and planetary science / Geochemistry/Astrochemistry

Research Activities

Published Papers

  • C. W. Hergenrother, C. K. Maleszewski, M. C. Nolan, J. Y. Li, C. Y. Drouet d’Aubigny, F. C. Shelly, E. S. Howell, T. R. Kareta, M. R.M. Izawa, M. A. Barucci, E. B. Bierhaus, H. Campins, S. R. Chesley, B. E. Clark, E. J. Christensen, D. N. DellaGiustina, S. Fornasier, D. R. Golish, C. M. Hartzell, B. Rizk, D. J. Scheeres, P. H. Smith, X. D. Zou, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M. K. Crombie, C. Lantz, M. R.M. Izawa, J. de Leon, J. Licandro, J. L.Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal
    Nature Communications 10 2019/12 [Refereed][Not invited]
     
    © 2019, The Author(s). During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission’s safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu’s surface to an upper limit of 150 g s –1 averaged over 34 min. Bennu’s disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu’s rotation rate is accelerating continuously at 3.63 ± 0.52 × 10 –6 degrees day –2 , likely due to the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, with evolutionary implications.
  • K. J. Walsh, E. R. Jawin, R. L. Ballouz, O. S. Barnouin, E. B. Bierhaus, H. C. Connolly, J. L. Molaro, T. J. McCoy, M. Delbo’, C. M. Hartzell, M. Pajola, S. R. Schwartz, D. Trang, E. Asphaug, K. J. Becker, C. B. Beddingfield, C. A. Bennett, W. F. Bottke, K. N. Burke, B. C. Clark, M. G. Daly, D. N. DellaGiustina, J. P. Dworkin, C. M. Elder, D. R. Golish, A. R. Hildebrand, R. Malhotra, J. Marshall, P. Michel, M. C. Nolan, M. E. Perry, B. Rizk, A. Ryan, S. A. Sandford, D. J. Scheeres, H. C.M. Susorney, F. Thuillet, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L.Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M.Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto
    Nature Geoscience 12 399  17520894 2019/05 [Refereed][Not invited]
     
    © 2019, Springer Nature Limited. In the version of this Article originally published, in the sentence “There are three identified boulders with long axes exceeding 40 m and more than 200 boulders larger than 10 m 2 ”, the term “10 m 2 ” should have been “10 m (ref. 2 )”. This has now been corrected.
  • D. S. Lauretta, D. N. DellaGiustina, C. A. Bennett, D. R. Golish, K. J. Becker, S. S. Balram-Knutson, O. S. Barnouin, T. L. Becker, W. F. Bottke, W. V. Boynton, H. Campins, B. E. Clark, H. C. Connolly, C. Y. Drouet d’Aubigny, J. P. Dworkin, J. P. Emery, H. L. Enos, V. E. Hamilton, C. W. Hergenrother, E. S. Howell, M. R.M. Izawa, H. H. Kaplan, M. C. Nolan, B. Rizk, H. L. Roper, D. J. Scheeres, P. H. Smith, K. J. Walsh, C. W.V. Wolner, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M.Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M. K. Crombie, C. Lantz, M. R.M. Izawa, J. de Leon
    Nature 568 55 - 60 00280836 2019/04 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth 1 . Bennu is a low-albedo B-type asteroid 2 that has been linked to organic-rich hydrated carbonaceous chondrites 3 . Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes 4 . The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimetre scale 5–11 . Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia 12 and radar polarization ratios 13 —which indicated a generally smooth surface covered by centimetre-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres 4 . We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.
  • D. N. DellaGiustina, J. P. Emery, D. R. Golish, B. Rozitis, C. A. Bennett, K. N. Burke, R. L. Ballouz, K. J. Becker, P. R. Christensen, C. Y. Drouet d’Aubigny, V. E. Hamilton, D. C. Reuter, B. Rizk, A. A. Simon, E. Asphaug, J. L. Bandfield, O. S. Barnouin, M. A. Barucci, E. B. Bierhaus, R. P. Binzel, W. F. Bottke, N. E. Bowles, H. Campins, B. C. Clark, B. E. Clark, H. C. Connolly, M. G. Daly, J. de Leon, M. Delbo’, J. D.P. Deshapriya, C. M. Elder, S. Fornasier, C. W. Hergenrother, E. S. Howell, E. R. Jawin, H. H. Kaplan, T. R. Kareta, L. Le Corre, J. Y. Li, J. Licandro, L. F. Lim, P. Michel, J. Molaro, M. C. Nolan, M. Pajola, M. Popescu, J. L.Rizos Garcia, A. Ryan, S. R. Schwartz, N. Shultz, M. A. Siegler, P. H. Smith, E. Tatsumi, C. A. Thomas, K. J. Walsh, C. W.V. Wolner, X. D. Zou, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M.Al Asad, C. L. Johnson, L. Philpott
    Nature Astronomy 3 341 - 351 2019/04 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. Establishing the abundance and physical properties of regolith and boulders on asteroids is crucial for understanding the formation and degradation mechanisms at work on their surfaces. Using images and thermal data from NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft, we show that asteroid (101955) Bennu’s surface is globally rough, dense with boulders, and low in albedo. The number of boulders is surprising given Bennu’s moderate thermal inertia, suggesting that simple models linking thermal inertia to particle size do not adequately capture the complexity relating these properties. At the same time, we find evidence for a wide range of particle sizes with distinct albedo characteristics. Our findings imply that ages of Bennu’s surface particles span from the disruption of the asteroid’s parent body (boulders) to recent in situ production (micrometre-scale particles).
  • O. S. Barnouin, M. G. Daly, E. E. Palmer, R. W. Gaskell, J. R. Weirich, C. L. Johnson, M. M. Al Asad, J. H. Roberts, M. E. Perry, H. C.M. Susorney, R. T. Daly, E. B. Bierhaus, J. A. Seabrook, R. C. Espiritu, A. H. Nair, L. Nguyen, G. A. Neumann, C. M. Ernst, W. V. Boynton, M. C. Nolan, C. D. Adam, M. C. Moreau, B. Rizk, C. Y. Drouet D’Aubigny, E. R. Jawin, K. J. Walsh, P. Michel, S. R. Schwartz, R. L. Ballouz, E. M. Mazarico, D. J. Scheeres, J. W. McMahon, W. F. Bottke, S. Sugita, N. Hirata, N. Hirata, S. I. Watanabe, K. N. Burke, D. N. DellaGiustina, C. A. Bennett, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M.Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront
    Nature Geoscience 12 247 - 252 17520894 2019/04 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission, Earth-based radar imaging gave an overview of (101955) Bennu’s shape. Here we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu’s top-like shape, considerable macroporosity and prominent surface boulders suggest that it is a rubble pile. High-standing, north–south ridges that extend from pole to pole, many long grooves and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin, which led to its current shape. Today, Bennu might follow a different evolutionary pathway, with an interior stiffness that permits surface cracking and mass wasting.
  • D. J. Scheeres, J. W. McMahon, A. S. French, D. N. Brack, S. R. Chesley, D. Farnocchia, Y. Takahashi, J. M. Leonard, J. Geeraert, B. Page, P. Antreasian, K. Getzandanner, D. Rowlands, E. M. Mazarico, J. Small, D. E. Highsmith, M. Moreau, J. P. Emery, B. Rozitis, M. Hirabayashi, P. Sánchez, S. Van wal, P. Tricarico, R. L. Ballouz, C. L. Johnson, M. M. Al Asad, H. C.M. Susorney, O. S. Barnouin, M. G. Daly, J. A. Seabrook, R. W. Gaskell, E. E. Palmer, J. R. Weirich, K. J. Walsh, E. R. Jawin, E. B. Bierhaus, P. Michel, W. F. Bottke, M. C. Nolan, H. C. Connolly, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront
    Nature Astronomy 3 352 - 361 2019/04 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. The top-shaped morphology characteristic of asteroid (101955) Bennu, often found among fast-spinning asteroids and binary asteroid primaries, may have contributed substantially to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of the OSIRIS-REx mission, we find a notable transition in Bennu’s surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennu’s surface has been most recently migrating towards its equator (given Bennu’s increasing spin rate), we infer that Bennu’s surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior is a mixture of voids and boulders. The presence of such heterogeneity and Bennu’s top shape are consistent with spin-induced failure at some point in its past, although the manner of its failure cannot yet be determined. Future measurements by the OSIRIS-REx spacecraft will provide insight into and may resolve questions regarding the formation and evolution of Bennu’s top-shape morphology and its link to the formation of binary asteroids.
  • V. E. Hamilton, A. A. Simon, P. R. Christensen, D. C. Reuter, B. E. Clark, M. A. Barucci, N. E. Bowles, W. V. Boynton, J. R. Brucato, E. A. Cloutis, H. C. Connolly, K. L. Donaldson Hanna, J. P. Emery, H. L. Enos, S. Fornasier, C. W. Haberle, R. D. Hanna, E. S. Howell, H. H. Kaplan, L. P. Keller, C. Lantz, J. Y. Li, L. F. Lim, T. J. McCoy, F. Merlin, M. C. Nolan, A. Praet, B. Rozitis, S. A. Sandford, D. L. Schrader, C. A. Thomas, X. D. Zou, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M.Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani
    Nature Astronomy 3 332 - 340 2019/04 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. Early spectral data from the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission reveal evidence for abundant hydrated minerals on the surface of near-Earth asteroid (101955) Bennu in the form of a near-infrared absorption near 2.7 µm and thermal infrared spectral features that are most similar to those of aqueously altered CM-type carbonaceous chondrites. We observe these spectral features across the surface of Bennu, and there is no evidence of substantial rotational variability at the spatial scales of tens to hundreds of metres observed to date. In the visible and near-infrared (0.4 to 2.4 µm) Bennu’s spectrum appears featureless and with a blue (negative) slope, confirming previous ground-based observations. Bennu may represent a class of objects that could have brought volatiles and organic chemistry to Earth.
  • K. J. Walsh, E. R. Jawin, R. L. Ballouz, O. S. Barnouin, E. B. Bierhaus, H. C. Connolly, J. L. Molaro, T. J. McCoy, M. Delbo’, C. M. Hartzell, M. Pajola, S. R. Schwartz, D. Trang, E. Asphaug, K. J. Becker, C. B. Beddingfield, C. A. Bennett, W. F. Bottke, K. N. Burke, B. C. Clark, M. G. Daly, D. N. DellaGiustina, J. P. Dworkin, C. M. Elder, D. R. Golish, A. R. Hildebrand, R. Malhotra, J. Marshall, P. Michel, M. C. Nolan, M. E. Perry, B. Rizk, A. Ryan, S. A. Sandford, D. J. Scheeres, H. C.M. Susorney, F. Thuillet, D. S. Lauretta, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J. P. Emery, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C.M. Susorney, E. A. Cloutis, R. D. Hanna, H. C. Connolly, F. Ciceri, A. R. Hildebrand, E. M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto
    Nature Geoscience 17520894 2019/01 [Refereed][Not invited]
     
    © 2019, The Author(s), under exclusive licence to Springer Nature Limited. Small, kilometre-sized near-Earth asteroids are expected to have young and frequently refreshed surfaces for two reasons: collisional disruptions are frequent in the main asteroid belt where they originate, and thermal or tidal processes act on them once they become near-Earth asteroids. Here we present early measurements of numerous large candidate impact craters on near-Earth asteroid (101955) Bennu by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, which indicate a surface that is between 100 million and 1 billion years old, predating Bennu’s expected duration as a near-Earth asteroid. We also observe many fractured boulders, the morphology of which suggests an influence of impact or thermal processes over a considerable amount of time since the boulders were exposed at the surface. However, the surface also shows signs of more recent mass movement: clusters of boulders at topographic lows, a deficiency of small craters and infill of large craters. The oldest features likely record events from Bennu’s time in the main asteroid belt.
  • Edward D. Young, Kyoshi Kuramoto, Rudolph A. Marcus, Hisayoshi Yurimoto, Stein B. Jacobsen
    Oxygen in the Solar System 68 187 - 218 1529-6466 2018/11 [Refereed][Not invited]
     
    © 2008, the Mineralogical Society of America. All rights reserved. In this chapter we compare and contrast chemical and photochemical pathways for massindependent fractionation (MIF) of oxygen isotopes in the solar nebula. We begin by assessing the galactic evolution model for oxygen isotope variation in the Solar System in order to compare the predictions of a leading nucleosynthetic model with those of the chemical models. There are two fundamentally different classes of possible chemical mechanisms for massindependent oxygen isotope fractionation in the early Solar System. One is symmetry-induced intramolecular vibrational disequilibrium of vibrationally excited reactant oxygen-bearing molecules. The other is isotope selective photodissociation of CO coupled with self-shielding and formation of H 2 O. Symmetry-induced fractionation is an experimentally verified process with solid theoretical foundations. It is observed to occur in Earth's atmosphere. It could have resulted in preservation of oxygen MIF effects only if mediated by dust grain surfaces. CO self-shielding is an attractive hypothesis for the origin of mass-independent oxygen isotope fractionation in the early Solar System because it appeals to a process that apparently occurs in the interstellar medium, but it lacks experimental verification. Three astrophysical settings for CO self-shielding are proposed as sites for generating δ 17 0 variability in the early Solar System. One is the inner annulus of the protostellar disk at relatively high temperature. Another is the surface of the disk high above the midplane where light from the central star grazes the gas and dust of the disk, resulting in a zone of active CO predissociation and self-shielding. Interstellar light illuminating the disk at high incident angles causes a similar horizon of CO photodestruction. Variations in 16 O could also have been inherited from self-shielding by CO in the molecular cloud that gave rise to the protosun. The overall consequence of CO self-shielding is conversion of CO gas to 16 O-poor H 2 O. A key difference between galactic evolution, chemically-induced MIF effects, and CO self-shielding is the predicted relative oxygen isotopic compositions of primeval dust and the Sun. Therefore, the oxygen isotopic composition of the Sun will be a crucial arbiter that may permit us to narrow the list of possible origins for oxygen MIF in the early Solar System.
  • Hisayoshi Yurimoto, Alexander N. Krot, Byeon Gak Choi, Jerome Aleon, Takuya Kunihiro, Adrian J. Brearley
    Oxygen in the Solar System 68 141 - 186 1529-6466 2018/11 [Refereed][Not invited]
     
    © 2008, the Mineralogical Society of America. All rights reserved. We review the oxygen isotopic compositions of chondrite components (refractory inclusions, chondrules, and matrix) and their inter- and intra- crystalline oxygen isotopic distributions. Primary oxygen isotopic compositions, acquired before planetesimal accretion, are easily disturbed by parent-body processes such as aqueous alternation and thermal metamorphism. Primary or original oxygen isotopic compositions of refractory inclusions (Ca-, Al-rich inclusions and amoeboid olivine aggregates) distribute along a slope-1 line on the three-oxygen isotope diagram over the range of -60% < SnO δ 17 O ≈ δ 18 < +10%. The variations suggest that oxygen isotopic compositions of the solar nebular gas temporally and spatially varied between l6 O-rich and 17 O-, 18 O-rich during refractory inclusion formation. On the other hand, primary minerals of most chondrules have small isotopic variations and are enriched in 1717 0 and l8 O relative to refractory inclusions, suggesting that chondrule formation occurred in 17 O-, 18 O-rich nebular gas. However, rare 16 O-rich chondrules have been found, suggesting some overlap in the timing of formation of chondrules and refractory inclusions in the solar nebula. Oxygen isotopic compositions of matrix grains distribute along the slope-1 line over the same range as refractory inclusions and chondrules. The similarity in oxygen isotopic distributions suggests that matrix was originally a mechanical mixture of nebular dusts co-generated with chondrules and refractory inclusions. Presolar grains with oxygen isotopic compositions that are clearly distinct from those of solar nebular materials are a trace component of chondrite matrices. Based on these oxygen isotopic characteristics, more than 99.5% of the solid materials in the nebula formed locally in the solar nebula, and the remainder formed in interstellar space. The astrophysical setting of chondrite component formation in the early Solar System is also discussed. Refractory inclusions and 16 O-rich matrix dusts formed around the inner edge of the solar nebula. On the other hand, most chondrules and 17 O-, 18 O-rich matrix dusts seem to have formed elsewhere in the solar nebula. Efficient, large-scale radial mixing of the solar nebular materials may have been an essential process in the formation of chondritic planetesimals.
  • Kakizawa Sho, Inoue Toru, Nakano Hideto, Kuroda Minami, Sakamoto Naoya, Yurimoto Hisayoshi
    AMERICAN MINERALOGIST 103 (8) 1221 - 1227 0003-004X 2018/08 [Refereed][Not invited]
  • Fei Hongzhan, Koizumi Sanae, Sakamoto Naoya, Hashiguchi Minako, Yurimoto Hisayoshi, Marquardt Katharina, Miyajima Nobuyoshi, Katsura Tomoo
    AMERICAN MINERALOGIST 103 (9) 1354 - 1361 0003-004X 2018/09 [Refereed][Not invited]
  • Yamamoto Daiki, Kuroda Minami, Tachibana Shogo, Sakamoto Naoya, Yurimoto Hisayoshi
    ASTROPHYSICAL JOURNAL 865 (2) 0004-637X 2018/10 [Refereed][Not invited]
  • Sugahara Haruna, Takano Yoshinori, Tachibana Shogo, Sugawara Iyo, Chikaraishi Yoshito, Ogawa Nanako O., Ohkouchi Naohiko, Kouchi Akira, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 53 (1) 5 - 20 0016-7002 2019 [Refereed][Not invited]
  • Bajo Ken-ichi, Fujioka Osamu, Itose Satoru, Ishihara Morio, Uchino Kiichiro, Yurimoto Hisayoshi
    SURFACE AND INTERFACE ANALYSIS 51 (1) 35 - 39 0142-2421 2019/01 [Refereed][Not invited]
  • Sas May, Kawasaki Noriyuki, Sakamoto Naoya, Shane Phil, Zellmer Georg F., Kent Adam J. R., Yurimoto Hisayoshi
    CHEMICAL GEOLOGY 513 153 - 166 0009-2541 2019/05 [Refereed][Not invited]
  • Piani Laurette, Yurimoto Hisayoshi, Remusat Laurent
    NATURE ASTRONOMY 2 (4) 317 - 323 2397-3366 2018/04 [Refereed][Not invited]
  • Lormand Charline, Zellmer Georg F., Nemeth Karoly, Kilgour Geoff, Mead Stuart, Palmer Alan S., Sakamoto Naoya, Yurimoto Hisayoshi, Moebis Anja
    MICROSCOPY AND MICROANALYSIS 24 (6) 667 - 675 1431-9276 2018/12 [Refereed][Not invited]
  • Kawasaki Noriyuki, Park Changkun, Sakamoto Naoya, Park Sun Young, Kim Hyun Na, Kuroda Minami, Yurimoto Hisayoshi
    EARTH AND PLANETARY SCIENCE LETTERS 511 25 - 35 0012-821X 2019/04 [Refereed][Not invited]
  • Kuroda Minami, Tachibana Shogo, Sakamoto Naoya, Yurimoto Hisayoshi
    AMERICAN MINERALOGIST 104 (3) 385 - 390 0003-004X 2019/03 [Refereed][Not invited]
  • Kuroda Minami, Tachibana Shogo, Sakamoto Naoya, Okumura Satoshi, Nakamura Michihiko, Yurimoto Hisayoshi
    AMERICAN MINERALOGIST 103 (3) 412 - 417 0003-004X 2018/03 [Refereed][Not invited]
  • Laurette Piani, Hisayoshi Yurimoto, Laurent Remusat
    2018/02 [Refereed][Not invited]
     Research paper (scientific journal) 
    Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, e.g. carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent body processes on the pre-accretion isotopic distributions. Here we report in situ micrometer-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites revealing a dominant deuterium-poor water component ({\delta}D = -350 +/- 40 permil) mixed with deuterium-rich organic matter. We suggest that this D-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetary disk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite ({\delta}DParis > -69 +/- 163 permil) in hydrated phases possibly present in the CM rock before alteration. The presence of the D-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System have been significant within the first million years of the Solar System history.
  • Fei Hongzhan, Koizumi Sanae, Sakamoto Naoya, Hashiguchi Minako, Yurimoto Hisayoshi, Marquardt Katharina, Miyajima Nobuyoshi, Katsura Tomoo
    EARTH AND PLANETARY SCIENCE LETTERS 484 204 - 212 0012-821X 2018/02 [Refereed][Not invited]
  • Wei Sun, Wei Sun, Takashi Yoshino, Naoya Sakamoto, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Earth and Planetary Science Letters 484 309 - 317 0012821X 2018/02 [Refereed][Not invited]
     
    © 2017 Elsevier B.V. Knowledge of the distribution of water in the Earth's mantle is key to understanding the mantle convection and geochemical evolution of the Earth. As wadsleyite and ringwoodite can incorporate large amounts of water in their crystal structures, proton conduction has been invoked to account for the widespread conductive anomalies observed in the mantle wedge, where descending slab stagnates at the transition zone. However, there is a lot of controversy on whether proton conduction by itself is able to explain such anomalies, because of large discrepancy in the extent of the water effect deduced from previous electrical conductivity measurements on hydrous polycrystalline wadsleyite and ringwoodite. Here we report the hydrogen self-diffusion coefficient obtained from H–D interdiffusion experiments in wadsleyite single-crystal couples. Our results demonstrate that the effect of water on the electrical conductivity of wadsleyite is limited and hydrous wadsleyite by itself is unable to explain conductive anomalies in the transition zone. In contrast, the expected hydrogen effective diffusion does not allow the wide propagation of water between the stagnant slab and surrounding mantle, probably leading to persistence of local water saturation and continuous release of supercritical fluids at the stagnant slab roof on geological time scales. This phenomenon provides an alternative explanation for both the high-conductivity and seismic-velocity anomalies observed in the mantle wedge at the transition-zone depth.
  • Hongzhan Fei, Hongzhan Fei, Michael Wiedenbeck, Naoya Sakamoto, Hisayoshi Yurimoto, Takashi Yoshino, Daisuke Yamazaki, Tomoo Katsura
    Physics of the Earth and Planetary Interiors 275 1 - 8 00319201 2018/02 [Refereed][Not invited]
     
    © 2017 Elsevier B.V. Oxygen self-diffusion coefficients (D Ox ) were measured in single crystals of dry synthetic iron-free olivine (forsterite, Mg 2 SiO 4 ) at a temperature of 1600 K and under pressures in the range 10 −4 to 13 GPa, using a Kawai-type multi-anvil apparatus and an ambient pressure furnace. Diffusion profiles were obtained by secondary ion mass spectrometry operating in depth profiling mode. D Ox in forsterite increases with increasing pressure with an activation volume of −3.9 ± 1.2 cm 3 /mol. Although Mg is the fastest diffusing species in forsterite under low-pressure conditions, O is the fastest diffusing species at pressures greater than ∼10 GPa. Si is the slowest throughout the stable pressure range of forsterite. Based on the observed positive and negative pressure dependence of D Ox and D Mg (Mg self-diffusion coefficient), respectively, D Ox + D Mg in forsterite decreases with increasing pressure, and then increases slightly at pressures greater than 10 GPa. This behavior is in agreement with the pressure dependence of ionic conductivity in forsterite based on conductivity measurements (Yoshino et al., 2017), and can be used to explain the conductivity increase from ∼300 km depth to the bottom of the asthenosphere.
  • Zellmer Georg F., Sakamoto Naoya, Matsuda Nozomi, Iizuka Yoshiyuki, Moebis Anja, Yurimoto Hisayoshi
    GEOCHIMICA ET COSMOCHIMICA ACTA 220 552 - 553 0016-7037 2018/01 [Refereed][Not invited]
  • Ai Cheng Zhang, Ai Cheng Zhang, Yi Fan Bu, Run Lian Pang, Naoya Sakamoto, Hisayoshi Yurimoto, Hisayoshi Yurimoto, Li Hui Chen, Jian Feng Gao, De Hong Du, Xiao Lei Wang, Ru Cheng Wang
    Geochimica et Cosmochimica Acta 220 125 - 145 00167037 2018/01 [Refereed][Not invited]
     
    © 2017 Elsevier Ltd Troilite-orthopyroxene intergrowths are present as a common material in the brecciated diogenite Northwest Africa (NWA) 7183. In this study, we report on the petrographic, mineralogical, and rare earth element abundances of the troilite-orthopyroxene intergrowths to constrain their origin and assess their implications for the diverse petrogenesis of diogenites. Two groups of troilite-orthopyroxene intergrowths with various grain sizes and mineral chemistry have been observed in NWA 7183. One group of intergrowths contains fine-grained ( < 5 μm) olivine and chromite as inclusions in orthopyroxene (10–20 μm in size). The other group, in which orthopyroxene is more fine-grained ( < 10 μm in size), is closely associated with coarse irregular olivine grains. The orthopyroxene grains in both groups of troilite-orthopyroxene intergrowths are depleted in Cr, Al, Ti, and Ca compared with diogenitic orthopyroxene. Based on the texture and mineral chemistry, we suggest that the two groups of troilite-orthopyroxene intergrowths formed via reactions between diogenitic olivine and S-rich vapors, probably at different temperatures. The fact that some of the intergrowths are included in diogenitic lithic clasts indicates that the formation of the host diogenite should postdate the formation of the majority of troilite-orthopyroxene intergrowths. This relationship further implies that not all of the diogenites are cumulates that directly crystallized from the Vestan magma ocean. Instead, they probably originated from partial melting and recrystallization of magma ocean cumulates. The replacement of olivine by troilite and orthopyroxene intergrowths can partly explain why the expected olivine-rich lithologies were not detected at the two south pole impact basins on Vesta.
  • N. Hiraishi, S. Kobayashi, H. Yurimoto, H. Yurimoto, J. Tagami
    Dental Materials 34 (4) e57 - e62 01095641 2018/04 [Refereed][Not invited]
     
    © 2018 The Academy of Dental Materials Objective: The dental caries is developed as a result of an alternative course of mineral gain and loss. In order to distinguish between intrinsic Ca (tooth-derived mineral) and extrinsic Ca (solution-derived mineral) uptakes, a44Ca doped pH-cycling was performed using44Ca (a stable calcium isotope) remineralization solution. Methods: The natural abundance of40Ca and44Ca is 96.9% and 2.1%, respectively. The remineralization solution was prepared using44Ca to contain 1.5 mmol/L CaCl2(44Ca), 0.9 mmol/L KH2PO4130 mmol/L KCl, 20 mmol/L HEPES at pH 7.0. The pH-cycling was conducted on bovine root dentin daily by demineralization (pH 5.0) for 2 h, incubation in 0% (control) and 0.2% NaF (900 ppm fluoride) for 2 h and44Ca doped remineralization for 20 h. After 14 days pH-cycling, the specimens were sectioned longitudinally. On the sectioned surface, isotope imaging of40Ca and44Ca labeled mineral distribution was observed by a high mass-resolution stigmatic secondary ion 77 (Camera IMS 1270, Gennevilliers Cedex, France). Results: Uptake of44Ca was greater in intensity for the 0.2% fluoride group than the control, especially in the superficial lesions. The control group showed40Ca (intrinsic) distribution in the subsurface lesions and in the superficial lesions, meanwhile the fluoride group showed40Ca distribution limited in subsurface lesions. The total Ca (44Ca +40Ca) image revealed more homogeneously for the control than the fluoride group. Significance: Since the fluoride-treated surface is more acid-resistant than intrinsic dentin, alternative minerals were dissolved from the intact intrinsic lesion in the demineralization cycle.
  • Tachibana S, Kouchi A, Hama T, Oba Y, Piani L, Sugawara I, Endo Y, Hidaka H, Kimura Y, Murata KI, Yurimoto H, Watanabe N
    Science advances 3 (9) eaao2538  2375-2548 2017/09 [Refereed][Not invited]
  • Yurimoto H.
    Encyclopedia of Earth Sciences Series 1129 - 1135 2018 [Refereed][Not invited]
  • Zolensky Michael E., Bodnar Robert J., Yurimoto Hisayoshi, Itoh Shoichi, Fries Marc, Steele Andrew, Chan Queenie H. -S., Tsuchiyama Akira, Kebukawa Yoko, Ito Motoo
    PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 375 (2094) 1364-503X 2017/05 [Refereed][Not invited]
  • Toru Matsumoto, S. Hasegawa, S. Nakao, M. Sakai, H. Yurimoto, H. Yurimoto
    Icarus 303 22 - 33 00191035 2018/03 [Refereed][Not invited]
     
    © 2017 The Authors We investigated impact crater structures on regolith particles from asteroid Itokawa using scanning electron microscopy. We observed the surfaces of 51 Itokawa particles, ranging from 15 µm to 240 µm in size. Craters with average diameters ranging from 10 nm to 2.8 µm were identified on 13 Itokawa particles larger than 80 µm. We examined the abundance, spatial distribution, and morphology of approximately 900 craters on six Itokawa particles. Craters with sizes in excess of 200 nm are widely dispersed, with spatial densities from 2.6 µm 2 to 4.5 µm 2 ; a fraction of the craters was locally concentrated with a density of 0.1 µm 2 . The fractal dimension of the cumulative crater diameters ranges from 1.3 to 2.3. Craters of several tens of nanometers in diameter exhibit pit and surrounding rim structures. Craters of more than 100 nm in diameter commonly have melted residue at their bottom. These morphologies are similar to those of submicrometer-sized craters on lunar regolith. We estimated the impactor flux on Itokawa regolith-forming craters, assuming that the craters were accumulated during direct exposure to the space environment for 10 2 to 10 4 yr. The range of impactor flux onto Itokawa particles is estimated to be at least one order of magnitude higher than the interplanetary dust flux and comparable to the secondary impact flux on the Moon. This indicates that secondary ejecta impacts are probably the dominant cratering process in the submicrometer range on Itokawa regolith particles, as well as on the lunar surface. We demonstrate that secondary submicrometer craters can be produced anywhere in centimeter- to meter-sized depressions on Itokawa's surface through primary interplanetary dust impacts. If the surface unevenness on centimeter to meter scales is a significant factor determining the abundance of submicrometer secondary cratering, the secondary impact flux could be independent of the overall shapes or sizes of celestial bodies, and the secondary impact flux could have similar values on Itokawa and the Moon.
  • Kawasaki Noriyuki, Itoh Shoichi, Sakamoto Naoya, Yurimoto Hisayoshi
    Geochimica et cosmochimica acta Geochimica et cosmochimica acta 201 83 - 102 0016-7037 2017/03 [Refereed][Not invited]
     
    Fluffy Type A Ca-Al-rich inclusions (CAIs) containing reversely zoned melilite crystals are suggested to be aggregates of direct condensates from solar nebular gas. We conducted an investigation of Al-26-Mg-26 systematics of a fluffy Type A CAI from Vigarano, named V2-01, with known oxygen isotopic distributions of reversely zoned melilite crystals; we also conducted oxygen isotope measurements of coexisting minerals. Two of six reversely zoned melilite crystals show continuous variations in magnesium isotopic composition, with delta Mg-25 decreasing along the inferred direction of crystal growth, which supports the idea that they originated through condensation. Petrography suggests that the constituent minerals of V2-01 formed in the following order: first spinel and fassaite enclosed by melilite, then reversely zoned melilite crystals, and spinel and diopside in the Wark-Lovering rim. The spinel enclosed by melilite has O-16-rich compositions (Delta O-17 similar to -24 parts per thousand) and on an Al-Mg evolutionary diagram plots along model isochron with an initial value of (Al-26/Al-27)(0) = (5.6 +/- 0.2) X 10(-5). The fassaite enclosed by melilite crystals shows variable oxygen isotopic compositions (Delta O-17 similar to -12 parts per thousand and -17 parts per thousand) and plots on an isochron with (Al-26/Al-27)(0) = (5.6 +/- 0.2) X 10(-5). The oxygen isotopic compositions of reversely zoned melilite showed continuous variations in Delta O-17 along the inferred direction of crystal growth, suggesting that surrounding nebular gas, during the formation of the reversely zoned melilite, changed from O-16-poor (Delta O-17 values larger than -10 parts per thousand) to O-16-rich (Delta 17 O similar to -25 parts per thousand). The six reversely zoned melilite crystals show indistinguishable initial Al-26/Al-27 values with an average (Al-26/Al-27)(0) of (4.7 +/- 0.3) X 10(-5), which is clearly distinguishable from the value of enclosed spinel and fassaite, indicating a younger formation age than the enclosed spinel and fassaite. The spinel and diopside from the Wark-Lovering rim show O-16-rich compositions (Delta O-17 similar to -23 parts per thousand) with (Al-26/Al-27)(0) = (4.5 +/- 0.4) X 10(-5). The values of (Al-26/Al-27)(0) are consistent with the formation sequence inferred from petrography. The formation period for the V2-01 CAI is estimated to be 0.18 +/- 0.07 Myr from the difference in initial (Al-26/Al-27) values. These data suggest that the oxygen isotopic composition of solar nebular gas surrounding the CAI changed from O-16-rich to O-16-poor and back to O-16-rich during the first similar to 0.2 Myr of Solar System formation. (C) 2016 Elsevier Ltd. All rights reserved.
  • Xu Fang, Yamazaki Daisuke, Sakamoto Naoya, Sun Wei, Fei Hongzhan, Yurimoto Hisayoshi
    EARTH AND PLANETARY SCIENCE LETTERS 459 332 - 339 0012-821X 2017/02 [Refereed][Not invited]
  • Noriyuki Kawasaki, Noriyuki Kawasaki, Steven B. Simon, Lawrence Grossman, Lawrence Grossman, Naoya Sakamoto, Hisayoshi Yurimoto, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 221 318 - 341 00167037 2017/01 [Refereed][Not invited]
     
    © 2017 The Author(s). TS34 is a Type B1 Ca-Al-rich inclusion (CAI) from the Allende CV3 chondrite, consisting of spinel, melilite, Ti-Al-rich clinopyroxene (fassaite) and minor anorthite in an igneous texture. Oxygen and magnesium isotopic compositions were measured by secondary ion mass spectrometry in spots of known chemical composition in all major minerals in TS34. Using the sequence of formation from dynamic crystallization experiments and from chemical compositions of melilite and fassaite, the oxygen isotopic evolution of the CAI melt was established. Oxygen isotopic compositions of the constituent minerals plot along the carbonaceous chondrite anhydrous mineral line. The spinel grains are uniformly 16 O-rich (δ 17 O=-22.7±1.7‰, 2SD), while the melilite grains are uniformly 16 O-poor (δ 17 O=-2.8±1.8‰) irrespective of their åkermanite content and thus their relative time of crystallization. The fassaite crystals exhibit growth zoning overprinting poorly-developed sector zoning; they generally grow from Ti-rich to Ti-poor compositions. The fassaite crystals also show continuous variations in δ 17 O along the inferred directions of crystal growth, from 16 O-poor (δ 17 O∼-3‰) to 16 O-rich (δ 17 O∼-23‰), covering the full range of oxygen isotopic compositions observed in TS34. The early-crystallized 16 O-poor fassaite and the melilite are in oxygen isotope equilibrium and formed simultaneously. The correlation of oxygen isotopic compositions with Ti content in the fassaite imply that the oxygen isotopic composition of the CAI melt evolved from 16 O-poor to 16 O-rich during fassaite crystallization, presumably due to oxygen isotope exchange with a surrounding 16 O-rich nebular gas. Formation of spinel, the liquidus phase in melts of this composition, predates crystallization of all other phases, so its 16 O-rich composition is a relic of an earlier stage. Anorthite exhibits oxygen isotopic compositions between δ 17 O∼-2‰ and -9‰, within the range of those of fassaite, indicating co-crystallization of these two minerals during the earliest to intermediate stage of fassaite growth. The melilite and fassaite yield an 26 Al- 26 Mg mineral isochron with an initial value of ( 26 Al/ 27 Al) 0 =(5.003±0.075)×10 -5 , corresponding to a relative age of 0.05±0.02Myr from the canonical Al-Mg age of CAIs. These data demonstrate that both 16 O-rich and 16 O-poor reservoirs existed in the solar nebula at least ∼0.05Myr after the birth of the Solar System.
  • Yuichi Nakazawa, Sachio Kobayashi, Hisayoshi Yurimoto, Hisayoshi Yurimoto, Fumito Akai, Hidehiko Nomura
    Quaternary International 10406182 2018/01 [Refereed][Not invited]
     
    © 2018 Elsevier Ltd and INQUA Archaeologists have long used obsidian hydration dating method to give chronometric dates for obsidian artifacts. Models using these equations independently employ different measurement systems, which are based on rim thicknesses determined by optical microscope and hydrogen depths measured by secondary ion mass spectrometry (SIMS), respectively, although the inconsistency of both measurements has been reported. Firstly, this paper describes a systematic comparison that was done on optical rim thicknesses and hydrogen depths by means of an isotope microscope, which provides micro-imaging with SIMS. Depth profiles of hydrogen were precisely obtained from the spots where optical measurements were taken on the archaeological obsidian flakes from two distinctive cultural horizons (older: Upper Paleolithic, younger: Initial Jomon) in the stratified open-air site of Jozuka in southern Kyushu (Japan). Secondarily, using the measurements of hydrogen depths that are the most consistent to the measurements of optical thicknesses, the estimated hydration rate of the Holocene (Initial Jomon) is slower than that of the Late Pleistocene (Upper Paleolithic), implying that the difference in hydration rates was due to the difference of intrinsic water content of obsidian and/or obsidian geochemistry. An application of micro-imaging with SIMS to measure hydrogen depths on obsidian shows promise as a tool for improving the practice of hydration dating and evaluating local climatic condition.
  • Abe Kenichi, Sakamoto Naoya, Krot Alexander N., Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 51 (1) 3 - 15 0016-7002 2017 [Refereed][Not invited]
  • Greenwood James P., Sakamoto Naoya, Itoh Shoichi, Warren Paul H., Singer Jack A., Yanai Kaori, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 51 (1) 105 - 114 0016-7002 2017 [Refereed][Not invited]
  • Singer Jack A., Greenwood James P., Itoh Shoichi, Sakamoto Naoya, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 51 (1) 95 - 104 0016-7002 2017 [Refereed][Not invited]
  • Yoshimura Shumpei, Nakamura Michihiko, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL GEOCHEMICAL JOURNAL 51 (3) 251 - 262 0016-7002 2017 [Refereed][Not invited]
     

    We carried out equilibrium experiments of the CO2-H2O-rhyolite system at 0.1–1.5 GPa and 850 and 1200°C to examine the solubility and speciation of CO2 in high-SiO2 rhyolite (SiO2 > 76 wt%). We observed that both CO2 molecules (CO2mol) and carbonate anions (CO32–) are dissolved in the quenched rhyolitic glasses based on infrared spectroscopy. This result contrasts with the general understanding that high-SiO2 rhyolitic melt dissolves CO2mol only. The concentrations of CO2mol and CO32– were 199–9200 ppm and 58–2100 ppm, respectively, as quantified based on the Beer-Lambert's law and newly determined extinction coefficients of 1192 ± 130 L·cm–1·mol–1 and 91 ± 28 L·cm–1·mol–1 for CO2mol and CO32–, respectively. The water content ranged from 2.6 to 6.1 wt%. Using the thermodynamic analysis, we calculated the partial molar volume of CO2mol to be = 24.9 ± 2.0 cm3/mol and enthalpy of dissolution to be ΔslnH = –22.2 ± 6.3 kJ/mol. Changes in volume and enthalpy upon the formation reaction of CO32– were calculated to be ΔrV = –8.6 ± 0.9 cm3/mol and ΔrH = +1.1 ± 4.4 kJ/mol, respectively.

  • Tonotani Azusa, Bajo Ken-ichi, Itose Satoru, Ishihara Morio, Uchino Kiichiro, Yurimoto Hisayoshi
    SURFACE AND INTERFACE ANALYSIS 48 (11) 1126 - 1126 1096-9918|0142-2421 2016/11 [Refereed][Not invited]
  • Bajo Ken-ichi, Itose Satoru, Matsuya Miyuki, Ishihara Morio, Uchino Kiichiro, Kudo Masato, Sakaguchi Isao, Yurimoto Hisayoshi
    SURFACE AND INTERFACE ANALYSIS 48 (11) 1193 - 1193 1096-9918|0142-2421 2016/11 [Refereed][Not invited]
  • L. Piani, S. Tachibana, T. Hama, H. Tanaka, H. Tanaka, Y. Endo, I. Sugawara, L. Dessimoulie, Y. Kimura, A. Miyake, J. Matsuno, A. Tsuchiyama, K. Fujita, S. Nakatsubo, H. Fukushi, S. Mori, T. Chigai, H. Yurimoto, A. Kouchi
    Astrophysical Journal 837 (1) 0004637X 2017/03 [Refereed][Not invited]
     
    © 2017. The American Astronomical Society. All rights reserved.. Refractory organic compounds formed in molecular clouds are among the building blocks of the solar system objects and could be the precursors of organic matter found in primitive meteorites and cometary materials. However, little is known about the evolutionary pathways of molecular cloud organics from dense molecular clouds to planetary systems. In this study, we focus on the evolution of the morphological and viscoelastic properties of molecular cloud refractory organic matter. We found that the organic residue, experimentally synthesized at ∼10 K from UV-irradiated H 2 O-CH 3 OH-NH 3 ice, changed significantly in terms of its nanometer- to micrometer-scale morphology and viscoelastic properties after UV irradiation at room temperature. The dose of this irradiation was equivalent to that experienced after short residence in diffuse clouds (≤10 4 years) or irradiation in outer protoplanetary disks. The irradiated organic residues became highly porous and more rigid and formed amorphous nanospherules. These nanospherules are morphologically similar to organic nanoglobules observed in the least-altered chondrites, chondritic porous interplanetary dust particles, and cometary samples, suggesting that irradiation of refractory organics could be a possible formation pathway for such nanoglobules. The storage modulus (elasticity) of photo-irradiated organic residues is ∼100 MPa irrespective of vibrational frequency, a value that is lower than the storage moduli of minerals and ice. Dust grains coated with such irradiated organics would therefore stick together efficiently, but growth to larger grains might be suppressed due to an increase in aggregate brittleness caused by the strong connections between grains.
  • Yurimoto Hisayoshi, Bajo Ken-ichi, Sakaguchi Isao, Suzuki Taku T., Jurewicz Amy J. G., Itose Satoru, Uchino Kiichiro, Ishihara Morio
    SURFACE AND INTERFACE ANALYSIS 48 (11) 1184 - 1184 1096-9918|0142-2421 2016/11 [Refereed][Not invited]
  • Hongo Hiromi, Sasaki Muneteru, Kobayashi Sachio, Hasegawa Tomoka, Yamamoto Tomomaya, Tsuboi Kanako, Tsuchiya Erika, Nagai Tomoya, Khadiza Naznin, Abe Miki, Kudo Ai, Oda Kimimitsu, Luiz de Freitas Paulo Henrique, Li Minqi, Yurimoto Hisayoshi, Amizuka Norio
    JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY 64 (10) 601 - 622 0022-1554|1551-5044 2016/11 [Refereed][Not invited]
  • Zellmer Georg F., Sakamoto Naoya, Hwang Shyh-Lung, Matsuda Nozomi, Iizuka Yoshiyuki, Moebis Anja, Yurimoto Hisayoshi
    FRONTIERS IN EARTH SCIENCE 4 2296-6463 2016/09 [Refereed][Not invited]
  • Zhang Ai-Cheng, Li Qiu-Li, Yurimoto Hisayoshi, Sakamoto Naoya, Li Xian-Hua, Hu Sen, Lin Yang-Ting, Wang Ru-Cheng
    NATURE COMMUNICATIONS 7 12844  2041-1723 2016/09 [Refereed][Not invited]
  • Pang RL, Zhang AC, Wang SZ, Wang RC, Yurimoto H
    Scientific reports 6 26063  2045-2322 2016/05 [Refereed][Not invited]
  • Steeve Gréaux, Steeve Gréaux, Yoshio Kono, Yanbin Wang, Akihiro Yamada, Akihiro Yamada, Chunyin Zhou, Zhicheng Jing, Zhicheng Jing, Toru Inoue, Yuji Higo, Tetsuo Irifune, Tetsuo Irifune, Naoya Sakamoto, Hisayoshi Yurimoto
    Geophysical Research Letters 43 (9) 4239 - 4246 0094-8276|1944-8007 2016/05 [Refereed][Not invited]
     
    © 2016. American Geophysical Union. All Rights Reserved.The elasticity of Al-bearing stishovite with 1.0, 3.3, and 4.5 wt % Al2O3 was investigated in the multianvil apparatus at high pressures and temperatures up to 21 GPa and 1700 K, by ultrasonic interferometry in conjunction with in situ X-ray techniques. The moduli KS and G are found to decrease with increasing Al2O3 content, while their pressure and temperature derivatives do not change in a significant manner for 1.0 and 3.3 wt % Al2O3. The temperature derivatives for 4.5 wt % Al2O3, however, are larger, which may result from a change in the Al substitution mechanism at high Al2O3 content. It is shown that acoustic velocities of any mid-ocean ridge basalt are lower by -0.4% than those calculated from pure stishovite data. Velocity perturbations up to -3.4% (VP) and -4.2% (VS) in subducted slabs are explained by the combination of the thermal equilibration (ΔT ~ 600 K) of the slab and Al enrichment in stishovite.
  • Hongzhan Fei, Hongzhan Fei, Sanae Koizumi, Naoya Sakamoto, Minako Hashiguchi, Minako Hashiguchi, Hisayoshi Yurimoto, Hisayoshi Yurimoto, Katharina Marquardt, Nobuyoshi Miyajima, Daisuke Yamazaki, Tomoo Katsura
    Earth and Planetary Science Letters 433 350 - 359 0012-821X 2016/01 [Refereed][Not invited]
     
    © 2015 Elsevier B.V..The creep in the Earth's interior is dominated either by diffusion creep which causes Newtonian mantle flow, or by dislocation creep which results in non-Newtonian mantle flow. Although previous deformation studies on olivine claimed a transition from dislocation creep to diffusion creep with depth in the upper mantle, they might misunderstand the creep rates due to experimental difficulties. Since creep in olivine is controlled by silicon diffusion, we measured the silicon grain-boundary diffusion coefficient in well-sintered iron-free olivine aggregates as a function of temperature, pressure, and water content, showing activation energy, activation volume, and water content exponent of 220±30 kJ/mol, 4.0±0.7 cm3/mol, and 0.26±0.07, respectively. Our results based on Si diffusion in forsterite predict that diffusion creep dominates at low pressures and low temperatures, whereas dislocation creep dominates under high pressure and high temperature conditions. Water has negligible effects on both diffusion and dislocation creep. There is a transition from diffusion creep in the shallow upper mantle to dislocation creep in deeper regions. This explains the seismic anisotropy increases at the Gutenberg discontinuity beneath oceans and at the mid-lithosphere discontinuity beneath continents.
  • Georg F. Zellmer, Naoya Sakamoto, Nozomi Matsuda, Yoshiyuki Iizuka, Anja Moebis, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 185 383 - 393 0016-7037 2016/01 [Refereed][Not invited]
     
    © 2016 Elsevier Ltd.Using a high resolution ion microprobe with SCAPS imaging, the peritectic reaction of forsterite+silica to enstatite was studied down to submicron level in a natural andesitic tephra from the Central Plateau of North Island, New Zealand. The fayalitic component of natural olivines is stable in high-silica melts, and therefore the reaction is in fact a two-step progress: 1. Dissolution of Mg-rich olivine, rate-limited by Fe-Mg interdiffusion at the crystal rim, results in enrichment of Fe in the crystal rim and of Mg in the c. 1μm wide melt boundary layer around the crystal. 2. Magnesian pyroxenes preferentially but not exclusively nucleate in the melt boundary layer and grow; as soon as these microlites touch the rim of the dissolving olivine, they shield the crystals from the silica-rich melt, thereby preventing further olivine dissolution. At this point, Fe-Mg interdiffusion begins to destroy the Fe-enrichment of the olivine rim. The reaction is completed when the dissolving olivine crystal is completely mantled by magnesian pyroxene microlites. Thick pyroxene mantles are likely the result of pyroxene overgrowth rather than due to peritectic transformation. The morphology of the olivine rim preserves information about the reaction history of the grain. Modeling of Fe-Mg interdiffusion in the olivine rim following its shielding from the melt by pyroxene overgrowth may yield the rates of olivine dissolution and the rates of pyroxene growth if temperature is known. For the tephra we have studied, microlite thermometry yields a temperature of 1137 (±41)°C, indicating an olivine dissolution rate of 3-6×10-11 ms-1 and an initially volumetric pyroxene growth rate of 2.2-5.6×10-21 m3 s-1. This points to timescales between olivine crystal uptake into the SiO2-rich melt and explosive eruption at the surface of a few hours to at most a day.
  • Ai Cheng Zhang, Ai Cheng Zhang, Shoichi Itoh, Shoichi Itoh, Hisayoshi Yurimoto, Wei Biao Hsu, Ru Cheng Wang, Lawrence A. Taylor
    Meteoritics and Planetary Science 51 (1) 56 - 69 1086-9379 2016/01 [Refereed][Not invited]
     
    © 2016 The Meteoritical Society.CM chondrites are a group of primitive meteorites that have recorded the alteration history of the early solar system. We report the occurrence, chemistry, and oxygen isotopic compositions of P-O-rich sulfide phase in two CM chondrites (Grove Mountains [GRV] 021536 and Murchison). This P-O-rich sulfide is a polycrystalline aggregate of nanometer-size grains. It occurs as isolated particles or aggregates in both CM chondrites. These grains, in the matrix and in type-I chondrules from Murchison, were partially altered into tochilinite; however, grains enclosed by Ca-carbonate are much less altered. This P-O-rich sulfide in Murchison is closely associated with magnetite, FeNi phosphide, brezinaite (Cr3S4), and eskolaite (Cr2O3). In addition to sulfur as the major component, this sulfide contains ∼6.3 wt% O, ∼5.4 wt% P, and minor amounts of hydrogen. Analyses of oxygen isotopes by SIMS resulted in an average δ18O value of -22.5 ‰ and an average Δ17O value of 0.2 ± 9.2 ‰ (2σ). Limited variations in both chemical compositions and electron-diffraction patterns imply that the P-O-rich sulfide may be a single phase rather than a polyphase mixture. Several features indicate that this P-O-rich sulfide phase formed at low temperature on the parent body, most likely through the alteration of FeNi metal (a) close association with other low-temperature alteration products, (b) the presence of hydrogen, (c) high Δ17O values and the presence in altered mesostasis of type-I chondrules and absence in type-II chondrules. The textural relations of the P-O-rich sulfide and other low-temperature minerals reveal at least three episodic-alteration events on the parent body of CM chondrites (1) formation of P-O-rich sulfide during sulfur-rich aqueous alteration of P-rich FeNi metal, (2) formation of Ca-carbonate during local carbonation, and (3) alteration of P-O-rich sulfide and formation of tochilinite during a period of late-stage intensive aqueous alteration.
  • Yun Yuan Chang, Yun Yuan Chang, Steven D. Jacobsen, Craig R. Bina, Sylvia Monique Thomas, Joseph R. Smyth, Daniel J. Frost, Tiziana Boffa Ballaran, Catherine A. McCammon, Erik H. Hauri, Toru Inoue, Hisayoshi Yurimoto, Yue Meng, Przemyslaw Dera
    Journal of Geophysical Research B: Solid Earth 120 (12) 8259 - 8280 2169-9313|2169-9356 2015/12 [Refereed][Not invited]
     
    ©2015. American Geophysical Union. All Rights Reserved.Review of recent mineral physics literature shows consistent trends for the influence of Fe and H2O on the bulk modulus (K0) of wadsleyite and ringwoodite, the major phases of Earth's mantle transition zone (410-660 km). However, there is little consensus on the first pressure derivative, K0′ = (dK/dP)P=0, which ranges from about 4 to >5 across experimental studies and compositions. Here we demonstrate the importance of K0′ in evaluating the bulk sound velocity of the transition zone in terms of water content and provide new constraints on the effect of H2O on K0′ for wadsleyite and ringwoodite by conducting a comparative compressibility study. In the experiment, multiple crystals of hydrous Fo90 wadsleyite containing 2.0 and 0.25 wt % H2O were loaded into the same diamond anvil cell, along with hydrous ringwoodite containing 1.4 wt % H2O. By measuring their pressure-volume evolution simultaneously up to 32 GPa, we constrain the difference in K0′ independent of the pressure scale, finding that H2O has no effect on K0′, whereas the effect of H2O on K0 is significant. The fitted K0′ values of hydrous wadsleyite (0.25 and 2.0 wt % H2O) and hydrous ringwoodite (1.4 wt % H2O) examined in this study were found to be identical within uncertainty, with K0′ ~3.7(2). New secondary-ion mass spectrometry measurements of the H2O content of these and previously investigated wadsleyite samples shows the bulk modulus of wadsleyite is reduced by 7.0(5) GPa/wt % H2O, independent of Fe content for upper mantle compositions. Because K0′ is unaffected by H2O, the reduction of bulk sound velocity in very hydrous regions of transition zone is expected to be on the order of 1.6%, which is potentially detectible in high-resolution, regional seismology studies.
  • Noriyuki Kawasaki, Chizu Kato, Chizu Kato, Shoichi Itoh, Shoichi Itoh, Shigeyuki Wakaki, Motoo Ito, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 169 99 - 114 0016-7037 2015/11 [Refereed][Not invited]
     
    © 2015 Elsevier Ltd. Disequilibrium oxygen isotopic distributions of Ca-Al-rich inclusions (CAIs) correspond to multiple melting events in the solar nebula. 26Al-26Mg systematics may be applicable for age differences among such melting events. We have carried out a coordinated study of detailed petrographic observations and in-situ oxygen and magnesium isotope measurements for a Type C CAI, EK1-04-2, from the Allende CV3 meteorite to determine the melting events and their ages. The CAI consists mainly of spinel, anorthite, olivine, and pyroxene, and has a core and mantle structure. Petrography of the core suggests that the crystallization sequence of the core minerals is from spinel, anorthite, olivine, and to pyroxene. The mantle has the same mineral assemblage as the core, and shows incomplete melting and solidification textures. Oxygen isotopic compositions of the minerals are distributed along the carbonaceous chondrite anhydrous mineral (CCAM) line (δ18O=-44‰ to +9‰), which indicates to preserve a chemical disequilibrium status in the CAI. Spinel shows a 16O-rich signature (δ18O~-43‰), while anorthite is 16O-poor (δ18O ~+8‰). Olivine and pyroxene in the core have the same oxygen isotopic composition (δ18O~-15‰), which indicates their equilibrium. Olivine and pyroxene in the mantle have variable oxygen isotopic compositions and are slightly depleted in 16O (δ18O=-13‰ to -4‰) compared with the same minerals in the core. The 26Al-26Mg systematics is consistent with the disequilibrium status observed according to the petrography and oxygen isotopes. Spinel is plotted on a line of (26Al/27Al)0=(3.5±0.2)×10-5, anorthite is plotted on a line of (-1±5)×10-7, and olivine and pyroxene in the core are plotted on a line of (-1±7)×10-6. Plots of olivine and pyroxene in the mantle are scattered below the isochron of these minerals in the core. This study indicates that the EK1-04-2 Type C CAI underwent multiple heating events after the formation of its CAI precursor. The precursor CAI was formed ~0.4Myr after the formation of the Solar System defined by canonical CAI formation. At least 1.6Myr after the precursor CAI formation, the CAI was partially melted and the melt exchanged oxygen isotopes with surrounding 16O-poor nebular gas. 16O-poor olivine and pyroxene in the core crystallized from the melt. Subsequently, Al-rich chondrules accreted onto the CAI, and the CAI experienced partial melting again and recrystallized to form the mantle. The oxygen and magnesium isotopes in anorthite were redistributed during thermal metamorphism in the Allende parent body. Our study reveals that the CAI had been retained in the solar nebula for at least 1.6Myr and underwent multiple melting events in the nebula, and oxygen and 26Al-26Mg systematics has been partially disturbed depending on crystal sizes by metamorphism on the parent body.
  • Cai Nao, Inoue Toru, Fujino Kiyoshi, Ohfuji Hiroaki, Yurimoto Hisayoshi
    AMERICAN MINERALOGIST 100 (10) 2330 - 2335 1945-3027|0003-004X 2015/10 [Refereed][Not invited]
  • Sun Wei, Yoshino Takashi, Sakamoto Naoya, Yurimoto Hisayoshi
    GEOPHYSICAL RESEARCH LETTERS 42 (16) 6582 - 6589 0094-8276|1944-8007 2015/08 [Refereed][Not invited]
  • Ai Cheng Zhang, Ai Cheng Zhang, Chi Ma, Naoya Sakamoto, Ru Cheng Wang, Wei Biao Hsu, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 163 27 - 39 0016-7037 2015/08 [Refereed][Not invited]
     
    © 2015 Elsevier Ltd. Titanium-rich minerals are common in Ca-Al-rich inclusions from primitive chondrites. They are important not only for testing the condensation models for a gas with a solar composition, but also for constraining the redox conditions of the early solar nebula. In this study, we report the detailed mineralogical features and its oxygen isotope compositions of a Ti-Sc-rich ultrarefractory inclusion A0031 from a CH3 chondrite Sayh al Uhaymir 290. The A0031 inclusion has a compact and layered texture with the interior consisting of panguite, Sc-rich anosovite, Ti-rich davisite, and anorthite. A few hexaferrum, perovskite, and spinel crystals are present as inclusions in these minerals. Outside of Ti-rich davisite are a layer of Al-Ti-rich diopside and two grains of enstatite. This texture strongly suggests that A0031 has a condensation origin. Panguite is its third occurrence in nature and similar in composition to the type panguite from the Allende meteorite. Sc-rich anosovite in A0031 has a chemical formula of (Ti4+,Ti3+,Mg,Sc,Al)3O5 with the pseudobrookite structure. This is the second report of Ti3O5 in nature, but is the first description of anosovite formed in the solar nebula as an ultrarefractory phase. The discovery of Sc-rich anosovite in A0031 reveals the stability of Ti3O5 in the early solar nebula and supports the prediction of previous equilibrium condensation calculations. The panguite, Sc-rich anosovite, and Ti-rich davisite in A0031 show a large variation in Ti3+/Titot. The primitive nature of A0031 implies that the variations in Ti3+/Titot among different Ti-rich minerals are primary features. We propose that the distribution of Ti3+ and Ti4+ could be controlled mainly by their various competition abilities of incorporating into these Ti-Sc-Al-rich minerals. Similarity of Ti3+/Titot value between Ti-rich davisite from A0031 and those in other carbonaceous chondrites indicates that most refractory inclusions might have formed in highly reducing nebular settings. The 16O-depleted isotope compositions of A0031 confirm the existence of diverse oxygen reservoirs for CH Ca-Al-rich inclusions in the solar nebula.
  • Okuchi Takuo, Purevjav Narangoo, Tomioka Naotaka, Lin Jung-Fu, Kuribayashi Takahiro, Schoneveld Louise, Hwang Huijeong, Sakamoto Naoya, Kawasaki Noriyuki, Yurimoto Hisayoshi
    AMERICAN MINERALOGIST 100 (7) 1483 - 1492 1945-3027|0003-004X 2015/07 [Refereed][Not invited]
     
    © 2015 by Walter de Gruyter Berlin/Boston. The presence of water in the Earth's deep mantle is an issue of increasing interest in the field of highpressure mineralogy. An important task for further advancing research in the field is to create homogeneous single crystals of candidate deep-mantle water-bearing minerals of 1 mm or larger in size, which is required for applying them for the time-of-flight (TOF) single-crystal Laue diffraction method with a third-generation neutron instrument. In this study, we perform several experiments to demonstrate an improved methodology for growing hydrous crystals of such large sizes at relevant transition zone and lower-mantle conditions via very slow cooling over a maximum period of 1 day. Successfully synthesized crystals using this methodology include dense hydrous magnesium silicate (DHMS) phase E, hydrous wadsleyite, hydrous ringwoodite, and bridgmanite (silicate perovskite). It is also demonstrated that these hydrous crystals can be grown from deuterium enriched starting materials in addition to those having a natural hydrogen isotope ratio. Magnitudes of chemical and crystallographic heterogeneities of the product crystals were characterized by comprehensive analysis of X-ray precession photography, single-crystal X-ray diffraction (SCXRD), field-emission scanning electron microscope (FE-SEM), electron probe microanalyzer (EPMA), secondary ion mass spectroscopy (SIMS), powder X-ray diffraction (PXRD), and TOF neutron powder diffraction (TOF-NPD). The product crystals were confirmed to be inclusion free and crystallographically homogeneous. Compositional and isotopic differences of major elements and hydrogen isotope abundances were lower than 1 and 3%, respectively, among intracrystals and intercrystals within each recovered sample capsule. Phase E crystals up to 600 μm in the largest dimension were grown at a constant temperature of 1100 °C kept for 3 h. Using a lattice parameter-to-temperature relation of phase E, the thermal gradient in the sample capsules for the phase E synthesis has been evaluated to be 20 °C/mm. Hydrous wadsleyite crystals up to 1100 μm in the largest dimension were grown at 1390 °C with a temperature reduction of 70 °C during heating for 10 h. Hydrous ringwoodite crystals up to 1000 μm in the largest dimension were grown at around 1400 °C with a temperature reduction of 110 °C during heating for 12 h. Bridgmanite crystals up to 600 μm in the largest dimension were grown at 1700 °C with a temperature reduction of 30 °C during heating for 12 h. A TOF single-crystal diffraction instrument has been successfully used for analyzing one of the hydrous wadsleyite crystals, which demonstrated that single crystals appropriate for their expected usage are created using the method proposed in the present study.
  • Bajo Ken-ichi, Olinger Chad T., Jurewicz Amy J. G., Burnett Donald S., Sakaguchi Isao, Suzuki Taku, Itose Satoru, Ishihara Morio, Uchino Kiichiro, Wieler Rainer, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 49 (5) 559 - 566 0016-7002|1880-5973 2015 [Refereed][Not invited]
  • Tsuboi K, Hasegawa T, Hongo H, Yurimoto H, Kobayashi S.
    Clinical calcium 25 (10) 1505 - 1511 2015 [Refereed][Not invited]
  • Hashiguchi Minako, Kobayashi Sachio, Yurimoto Hisayoshi
    GEOCHEMICAL JOURNAL 49 (4) 377 - 391 0016-7002|1880-5973 2015 [Refereed][Not invited]
  • Yurimoto Hisayoshi, Sano Yuji, Akagi Tasuku
    GEOCHEMICAL JOURNAL 49 (3) 319  0016-7002 2015 [Refereed][Not invited]
  • [Bone Cell Biology Assessed by Microscopic Approach. Novel insights about bone tissue by new microscopy systems].
    Tsuboi K, Hasegawa T, Hongo H, Yurimoto H, Kobayashi S
    Clinical calcium 25 (10) 1505 - 1511 0917-5857 2015/10 [Refereed][Not invited]
  • Matsui Y, Sakamoto A, Nakao S, Taniguchi T, Matsushita T, Shirasaki N, Sakamoto N, Yurimoto H
    Environmental science & technology 48 (18) 10897 - 10903 1520-5851|0013-936X 2014/09 [Refereed][Not invited]
  • Ai Cheng Zhang, Ai Cheng Zhang, Shoichi Itoh, Shoichi Itoh, Naoya Sakamoto, Ru Cheng Wang, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 130 78 - 92 0016-7037 2014/04 [Refereed][Not invited]
     
    Aluminum-rich chondrules are one of the most interesting components of primitive chondrites, because they have characteristics that are similar to both Ca, Al-rich inclusions (CAIs) and ferromagnesian chondrules. However, their precursor and formation history remain poorly constrained, especially with respect to their oxygen isotopic distributions. In this study, we report on the petrography, mineralogy, oxygen isotope ratios, and rare-earth-element compositions of a sapphirine-bearing Al-rich chondrule (SARC) in the ungrouped chondrite Dar al Gani (DaG) 978. The SARC has a complex core-mantle-rim texture; while both the core and the mantle are mainly composed of Al-rich enstatite and anorthite with minor amounts of mesostasis, these regions are distinguished by the presence of Fe-rich spinel and sapphirine in the core and their absence in the mantle. The rim of the SARC consists mainly of Fe-rich olivine, enstatite, and Fe-Ni metal. Spinel and some olivine grains in the SARC are 16O-rich, with δ17O values down to -20‰ and -23‰, respectively. Enstatite, sapphirine, and most olivine grains have similar δ17O values (~ -7‰), which are lower than those of anorthite and the mesostasis (including augite therein) (δ17O: ~ -3‰). Mesostasis from both the core and mantle have Group II rare-earth-element (REE) patterns; however, the core mesostasis has higher REE concentrations than the mantle mesostasis. These observations provide a strong indication that the SARC formed by the melting and crystallization of a mixture of materials from Group II CAIs and ferromagnesian chondrules. Both spinel and olivine with 16O-rich features could be of relict origin. The 16O-poor isotopic compositions of most components in Al-rich chondrules can be explained by oxygen isotopic exchange between the melt and 16O-poor nebular gas (δ17O: ~ -7‰) during melting in chondrule-forming regions; whereas the anorthite and mesostasis could have experienced further oxygen isotopic exchange with a relatively 16O-poor reservoir (δ17O: ~ -3‰) on the parent body, likely during fluid-assisted thermal metamorphism. During the same thermal metamorphism event, spinel, olivine, some enstatite, and the mesostasis experienced Mg-Fe exchange to various extents. © 2013 Elsevier Ltd.
  • Kuga Y, Sakamoto N, Yurimoto H
    The New phytologist 202 (2) 594 - 605 0028-646X|1469-8137 2014/04 [Refereed][Not invited]
  • Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 159 306  00167037 2015/06 [Refereed][Not invited]
  • Jen Chieh Shiao, Shoichi Itoh, Hisayoshi Yurimoto, Yoshiyuki Iizuka, Yun Chih Liao
    Deep-Sea Research Part I: Oceanographic Research Papers 84 50 - 58 0967-0637|1879-0119 2014/02 [Refereed][Not invited]
     
    This study using tuna otoliths as working standards established a high lateral resolution and precision analysis to measure δ18Ootolith by secondary ion mass spectrometry. This analytical approach of the ion probe was applied to deep-sea fishes to reconstruct the likely depths inhabited by the fishes at different life history stages based on the measured δ18Ootolith values as a proxy of water temperature. Dramatic increases up to 5-6‰ in δ18Ootolith, representing a temperature decrease of approximately 20°C, were detected in a blind cusk eel (Barathronus maculatus) otolith and in the otoliths of Synaphobranchus kaupii during leptocephalus metamorphosis to glass eel, inferred from the drop of otolith Sr/Ca ratios and increase of otolith growth increment width. δ18Ootolith profiles clearly divided the fish's life history into a planktonic stage in the mixed layer of the ocean and a benthic stage on the deep-sea ocean bottom. The habitat shift signal was recorded within a 150μm width of otolith growth zone, which was too narrow to be clearly detected by mechanical drilling and conventional isotopic ratio mass spectrometry. However, variations down to -7‰ were found in δ18Ootolith profiles as the result of Cs2+ beam sputter in the core and larval portions of the otoliths. Carbon mapping by electron probe microanalyzer and staining by toluidine blue suggested abundant proteins existed in the areas with anomaly negative δ18Ootolith values, which cannot be interpreted as a habitat change but due to the isotopic fractionation by O emission from the proteins. These results implied that careful design and understanding of the chemical composition of the analytical areas or tracks on the heterogeneous otolith was essential for highly accurate and precise analysis. © 2013 Elsevier Ltd.
  • Georg F. Zellmer, Georg F. Zellmer, Shyh Lung Hwang, Naoya Sakamoto, Yoshiyuki Iizuka, Sakiko Harada, Jun Ichi Kimura, Yoshihiko Tamura, Hisayoshi Yurimoto
    Geological Society Special Publication 410 (1) 219 - 236 03058719 2015/01 [Refereed][Not invited]
     
    © 2015 The Geological Society of London. Pleistocene basalts from Daisen and Mengameyama in the SW Japan volcanic arc of western Honshu are characterized by an abundance of olivine crystals with Fe-rich rims. At Daisen, these have previously been interpreted to have formed from their host melt by equilibrium crystal fractionation and by disequilibrium fractionation during supercooling. Here we use combined electron probe microanalysis, isotopography, transmission electron microscopy and selected area electron diffraction to show that crystal rims are significantly enriched in aluminium (up to c. 1 wt%) and hydrogen (up to c. 10 000 ppm) hosted in oriented low-density amorphous domains. These domains are interpreted to have formed by melting of deuteric and/or post-deuteric metasomatic alteration minerals upon uptake of older olivine crystals into fresh, initially aphyric host melts up to a few hours prior to eruption. It is argued that uptake of variably altered crystals into initially aphyric or sparsely phyric melts may be a common process at subduction zones, and can account for typical disequilibrium textures displayed by arc magmas erupted in SW Japan and elsewhere. Analyses of the altered crystal cargo in arc volcanic rocks therefore provides an important tool for understanding subvolcanic hydrothermal systems and the interaction of ascending melts with such systems.
  • Masayuki Uesugi, Ryo Noguchi, Tooru Matsumoto, Junya Matsuno, Takashi Nagano, Akira Tsuchiyama, Shigenori Harada, Kaori Yokoyama, Yoshiaki Yodo, Noboru Takeda, Toru Yada, Shogo Yakame, Shogo Yakame, Yuzuru Karouji, Yukihiro Ishibashi, Masanao Abe, Tatsuaki Okada, Akio Fujimura, Mitsuru Ebihara, Fumio Kitajima, Keisuke Nagao, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 49 (7) 1186 - 1201 1945-5100|1086-9379 2014/01 [Refereed][Not invited]
     
    We report the investigation of cutting methods for Hayabusa samples. The purpose of our study is to explore the possibility of applying multiple analyses to a single particle effectively. We investigated the cutting performance of a blade dicing saw, laser, focused ion beam (FIB), and physical breaking by microindenter. Cutting performance was examined by estimating the aspect ratio of the cut slit, i.e., depth over width of the slit. We also investigated the possible contamination and sample damage by cutting. The result of the investigation shows that we can cut the samples from <50 μm to 500 μm using those methods with aspect ratios from 10 to 20, although they would introduce some contamination or damage to the samples. Our investigations also provide an important basis for the analysis of samples obtained by future sample return missions. © The Meteoritical Society, 2014.
  • Hisayoshi Yurimoto, Hisayoshi Yurimoto, Shoichi Itoh, Shoichi Itoh, Michael Zolensky, Minoru Kusakabe, Akiya Karen, Robert Bodnar
    Geochemical Journal 48 (6) 549 - 560 0016-7002|1880-5973 2014/01 [Refereed][Not invited]
     
    Copyright © 2014 by The Geochemical Society of Japan. Determination of isotopic composition of extraterrestrial liquid water provides important information regarding the origin of water on Earth and the terrestrial planets. Fluid inclusions in halite of ordinary chondrites are the only direct samples of extraterrestrial liquid water available for laboratory measurements. We determined H and O isotopic compositions of this water by secondary ion mass spectrometry equipped with a cryogenic apparatus for sample cooling. Isotopic compositions of the fluid inclusion fluids (brines) were highly variable among individual inclusions, -400 < δD < +1300‰; -20 < Δ17O < +30‰, indicating that these aqueous fluids were in isotopic disequilibrium before trapping in halite on asteroids. The isotopic variation of fluids shows that various degrees of water-rock interaction had been underway on the asteroids before trapping between D-rich-16O-poor aqueous fluid, D-poor-16O-rich aqueous fluid, and asteroidal rock by delivery of cometary water onto hydrous asteroids. This may be a fundamental mechanism in the evolution of modern planetary water.
  • Yahachi Saito, Hisayoshi Yurimoto
    Surface and Interface Analysis 46 (12-13) 1119 - 1120 1096-9918|0142-2421 2014/01 [Refereed][Not invited]
  • Watanabe T, Kouho R, Katayose T, Kitajima N, Sakamoto N, Yamaguchi N, Shinano T, Yurimoto H, Osaki M
    Plant, cell & environment 37 (1) 45 - 53 1365-3040|0140-7791 2014/01 [Refereed][Not invited]
  • Minako Hashiguchi, Sachio Kobayashi, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 122 306 - 323 0016-7037 2013/12 [Refereed][Not invited]
     
    Eighty-five D-rich carbonaceous particles were identified in the matrix of the NWA 801 CR2 chondrite using isotope microscopy. The occurrence of 67 D-rich carbonaceous particles was characterized using secondary electron microscopy combined with X-ray elemental mapping. The close association of H and C, and D-enrichment suggests that the D-rich carbonaceous particles correspond to organic matter. The D-rich organic particles were scattered ubiquitously throughout the matrix at a concentration of approximately 660ppm. The morphology of the D-rich carbonaceous particles is globular up to about 1μm in diameter and is classified into four types: ring globules, round globules, irregular-shaped globules, and globule aggregates. The ring globules are ring-shaped organic matter containing silicate and/or oxide, with or without a void in the center. This is the first report of silicate and oxide grains surrounded by D-rich organic matter. The globule aggregates are composed of several D-rich organic globules mixed with silicates. Morphology of ring globules is very similar to core-mantle grain produced in the molecular cloud or in the outer solar nebula inferring by astronomy, suggesting that the organic globules have formed by UV photolysis in the ice mantle. Silicates or oxides attached to D-rich organic globules are the first observation among chondrites so far and may be unique nature of CR2 chondrites. The hydrogen isotopic compositions of the ring globules, round globules, irregular-shaped globules, and globule aggregates are δD=3000-4800, 2900-8100, 2700-11,000, and 2500-11,000‰, respectively. Variations of D/H ratio of these organic globules seemed to be attributed to variations of D/H ratio of the organic radicals or differences of content of the D-rich organic radicals. There are no significant differences in the hydrogen isotopic compositions among the four types of D-rich carbonaceous matter. The D-enrichments suggest that these organic globules have formed in a cold molecular cloud and/or the outer protoplanetary disk of the early solar system. The oxygen isotopic compositions of the silicates and oxides attached to the ring globules and globule aggregates range from δ17O=-49 to 50‰ and δ18O=-46 to 64‰. The oxygen isotopic compositions are not distinct from those of solar system materials, which suggests that the organic globules were formed in the outer solar system rather than in the presolar environment. Therefore, it is possible that the ring globules and globule aggregates in NWA 801 may have formed in the outer protoplanetary disk of the early solar system. Organic globules that exhibit clear presolar origin were not identified in this study. The lack of clear presolar signatures might suggest that modifications of isotopic compositions or morphologies of the presolar organic matter occurred in the early solar nebula. © 2013.
  • Minako Hashiguchi, Isao Sakaguchi, Naoya Sakamoto, Hisayoshi Yurimoto, Shunichi Hishita, Naoki Ohashi, Naoki Ohashi
    Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan 121 (1420) 1004 - 1007 1348-6535|1882-0743 2013/12 [Refereed][Not invited]
     
    We studied the diffusion of Zn in dense SnO2 ceramics by using secondary ion mass spectrometry (SIMS). Dense SnO2 ceramics with additives of 6mol.% MgO and 0.2mol.% Sb2O5 were synthesized, and Zn was implanted in the SnO2 ceramics by ion implantation technique. The implanted samples were annealed at 850-1200°C, and the concentration profiles of Zn were evaluated by SIMS. The temperature dependence of Zn diffusion at 850-950°C could be expressed as DZn[cm2/s] = 3.3 × 106exp(-463.5[kJ/mol]/RT). These results in relation to the fabrication process of SnO2 with added ZnO was then discussed. © 2013 The Ceramic Society of Japan. All rights reserved.
  • Georg F. Zellmer, Georg F. Zellmer, Naoya Sakamoto, Yoshiyuki Iizuka, Masaya Miyoshi, Yoshihiko Tamura, Hui Ho Hsieh, Hisayoshi Yurimoto
    Geological Society Special Publication 385 (1) 161 - 184 03058719 2014/02 [Refereed][Not invited]
     
    Minerals of mafic rocks from theSWJapan arc have been studied to deduce P-T-XH2O conditions and their variations in mafic arc magmas. Two-pyroxene thermobarometry of magmas from several volcanoes yields constant temperatures and variable pressures. MELTS fractional crystallization modelling is employed to show that such 'pseudo-decompression paths' (PDPs) are artefacts that derive from uptake of pyroxene antecrysts formed at a range of crustal levels by isobaric cooling of previously intruded mafic melts. It is shown that PDPs can be used to constrain oxygen fugacities and initial water contents of the intruded magmas. These constraints, and plagioclase hygrometry, indicate that initial melt H2O contents change systematically along the SW Japan arc. Direct determination of hydrogen in olivine by secondary ion mass spectrometry yields consistently low olivine H2O contents of 11+4 ppm (1s), with little, if any, along-arc variations. MELTS modelling indicates that crystallization of calcic plagioclase and olivine dominantly occurs during upper crustal differentiation of mafic melts. The combined data indicate that aphyric melts are released from the mantle wedge, taking up most if not all crystals from previously intruded plutonic rocks during rapid magma ascent to the surface. © The Geological Society of London 2014.
  • Hyodo H, Terao A, Furukawa J, Sakamoto N, Yurimoto H, Satoh S, Iwai H
    PloS one 8 (11) e78949  1932-6203 2013/11 [Refereed][Not invited]
  • S. Wakita, S. Wakita, T. Nakamura, T. Ikeda, H. Yurimoto
    Meteoritics and Planetary Science 49 (2) 228 - 236 10869379 2014/02 [Refereed][Not invited]
     
    We modeled the possible parent bodies of Itokawa, which was heated within by the decay energy of 26Al. Based on mineralogic studies of dust particles derived from Itokawa by the Hayabusa spacecraft, it appeared that they were thermally metamorphosed at a peak temperature of 800 °C, and kept at 700 °C or higher at 7.6 Myr after CAI formation. Our numerical results show that the parent bodies of Itokawa would have been larger than 20 km in radius and accreted at a period between 1.9 and 2.2 Myr after CAI formation, to satisfy mineralogic and isotopic evidence from dust particles. © The Meteoritical Society, 2013.
  • Isao Sakaguchi, Naoya Sakamoto, Minako Hashiguchi, Minako Hashiguchi, Hisayoshi Yurimoto, Shunichi Hishita, Naoki Ohashi
    Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan 121 (1419) 956 - 959 18820743 2013/11 [Refereed][Not invited]
     
    We investigated the effect of zinc oxide addition for the defects in the dense SnO2 ceramics. Cathode and photoluminescence properties revealed the luminescence originated to oxygen vacancies in SnO2 grains and the presence of non-radiative defect at the grain boundaries. The oxygen diffusion profile showed that the oxygen diffusion was controlled by the limited process at the surface and uniform concentration of 18O at the grain boundaries inner side of sample. This sample exhibited a low Zn concentration in grains and a high Zn concentration at grain boundaries.We conclude that segregation of Zn at grain boundaries prevents SnO2 from decomposing at high temperatures, enabling dense SnO2 ceramics to be obtained. © 2013 The Ceramic Society of Japan. All rights reserved.
  • Ai Cheng Zhang, Ai Cheng Zhang, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 48 (9) 1651 - 1677 1945-5100|1086-9379 2013/09 [Refereed][Not invited]
     
    Dar al Gani (DaG) 978 is an ungrouped type 3 carbonaceous chondrite. In this study, we report the petrography and mineralogy of Ca,Al-rich inclusions (CAI), amoeboid olivine aggregates (AOAs), chondrules, mineral fragments, and the matrix in DaG 978. Twenty-seven CAIs were found: 13 spinel-diopside-rich inclusions, 2 anorthite-rich inclusions, 11 spinel-troilite-rich inclusions, and 1 spinel-melilite-rich inclusion. Most CAIs have a layered texture that indicates a condensation origin and are most similar to those in R chondrites. Compound chondrules represent a high proportion (approximately 8%) of chondrules in DaG 978, which indicates a local dusty chondrule-forming region and multiple heating events. Most spinel and olivine in DaG 978 are highly Fe-rich, which corresponds to a petrologic type of >3.5 and a maximum metamorphic temperature of approximately 850-950 K. This conclusion is also supported by other observations in DaG 978: the presence of coarse inclusions of silicate and phosphate in Fe-Ni metal, restricted Ni-Co distributions in kamacite and taenite, and low S concentrations in the matrix. Mineralogic records of iron-alkali-halogen metasomatism, such as platy and porous olivine, magnetite, hedenbergite, nepheline, Na-rich in CAIs, and chlorapatite, are present, but relatively limited, in DaG 978. The fine-grained, intergrowth texture of spinel-troilite-rich inclusions was probably formed by reaction between pre-existing Al-rich silicates and shock-induced, high-temperature S-rich gas on the surface of the parent body of DaG 978. A shock-induced vein is present in the matrix of DaG 978, which indicates that the parent body of DaG 978 at least experienced a shock event with a shock stage up to S3. © The Meteoritical Society, 2013.
  • Hamasaki T, Matsumoto T, Sakamoto N, Shimahara A, Kato S, Yoshitake A, Utsunomiya A, Yurimoto H, Gabazza EC, Ohgi T
    Nucleic acids research 41 (12) 126  0305-1048|1362-4962 2013/07 [Refereed][Not invited]
  • Hironori Negishi, Shoji Arai, Hisayoshi Yurimoto, Shoichi Ito, Satoko Ishimaru, Akihiro Tamura, Norikatsu Akizawa
    Lithos 164-167 22 - 35 1872-6143|0024-4937 2013/04 [Refereed][Not invited]
     
    Peculiar dunites, in part wehrlitic, that contain up to 3vol.% sulfides from a thick (~1000m) Moho transition zone (MTZ) are found along Wadi Thuqbah in the northern Oman ophiolite. We discuss their relevance to the formation of Cyprus-type massive sulfide deposits near the surface. Field observations suggest that the sulfide-rich MTZ dunites are of late-intrusive origin. The sulfides form composite grains with magnetite and form angular clasts, which are enclosed or cut by magnetite. The sulfide part is composed of homogeneous pyrrhotite and vermicular intergrowth of pyrrhotite and pentlandite. Sulfide inclusions in clinopyroxene comprise pyrrhotite with pentlandite blebs, free of magnetite. Olivines in the sulfide-rich dunite characteristically show low NiO contents (0.1-0.3wt.%) relative to a high Fo value (~91), and as such they do not lie on a Fo-NiO trend of ordinary sulfide-free MTZ dunites-wehrlites. This low-Ni olivine was precipitated from a high-Mg magma that had segregated Ni-rich sulfide melts. The pentlandite-pyrrhotite intergrowth was formed by subsolidus exsolution at low temperatures (<200°C) from high-temperature mono-sulfide solid solution. Iron released from olivine during serpentinization produced magnetite, which was combined with the sulfides to form the composite grains. In-situ S isotope ratios of the sulfides (δ34S=0.7-2.8) are slightly higher than mantle values but lie within the range for magmas from oceanic island arcs, such as the Marianas. The δ34S are lower than those for sulfate from seawater and MORB-related sulfides, such as TAG (Trans-Atlantic Geotraverse) deposits. One of the Cyprus type massive sulfide deposits (Aarja) from the crustal section of the same area shows similar S isotope ratios to the sulfides in the Thuqbah sulfide-rich dunites/wehrlites, indicating their genetic linkage. The Aarja sulfide deposit was formed within the V2 lavas, which are relatively sulfur-rich and of an off-axis origin, as a result of high-temperature seawater circulation. The Thuqbah sulfide-rich dunite possibly represents an igneous root of the Cyprus-type massive sulfide deposit of Aarja formed in an off-ridge magmatic-hydrothermal system. © 2012 Elsevier B.V.
  • Kyoko Imamura, Yoshihide Ogasawara, Hisayoshi Yurimoto, Minoru Kusakabe
    International Geology Review 55 (4) 453 - 467 1938-2839|0020-6814 2013/03 [Refereed][Not invited]
     
    We analysed isotopic compositions of metamorphic microdiamond secondary ion mass spectrometry. Typical microdiamonds in this dolomite marble show star-shaped morphologies (S-type) consisting of single-crystal cores and polycrystalline rims. Four S-type microdiamonds and two R-type microdiamonds (single crystals with rugged surfaces) were analysed using a 5 μm diameter ion beam. S-type microdiamonds have heterogeneous carbon isotopic compositions even in a single grain. Analysis of a typical S-type microdiamond (no. xx01-1-13) revealed clear difference in δ13C between core and rim. The rim shows lighter isotopic compositions ranging from -17.2% to -26.9%, whereas the core is much heavier, with δ13C ranging from -9.3% to -13.0%. The δ13C values of R-type microdiamonds fall into narrow ranges from -8.3% to -14.9% for no. xx01-1-10 and from -8.3% to -15.3% for no. xx01-1-16. These δ13C values are similar to those of the S-type microdiamond cores. The R-type probably formed at the same stage as the core of the S-type, whereas rim growth at a second stage did not occur or occurred very weakly in R-type microdiamonds. These carbon isotopic data support the two-stage growth of microdiamonds in the Kokchetav ultrahigh-pressure host rock. To explain the second stage growth of S-type microdiamonds, we postulate a simple fluid infiltration of light carbon from neighbouring gneisses into the dolomite marble. © 2013 Taylor & Francis.
  • Ebata S, Ishihara M, Kumondai K, Mibuka R, Uchino K, Yurimoto H
    Journal of the American Society for Mass Spectrometry 24 (2) 222 - 229 1879-1123|1044-0305 2013/02 [Refereed][Not invited]
  • J. M. Paque, S. R. Sutton, S. B. Simon, J. R. Beckett, D. S. Burnett, L. Grossman, L. Grossman, H. Yurimoto, S. Itoh, H. C. Connolly, H. C. Connolly, H. C. Connolly, H. C. Connolly
    Meteoritics and Planetary Science 48 (10) 2015 - 2043 10869379 2013/10 [Refereed][Not invited]
     
    Ti valence measurements in MgAl2O4 spinel from calcium-aluminum-rich inclusions (CAIs) by X-ray absorption near-edge structure (XANES) spectroscopy show that many spinels have predominantly tetravalent Ti, regardless of host phases. The average spinel in Allende type B1 inclusion TS34 has 87% Ti+4. Most spinels in fluffy type A (FTA) inclusions also have high Ti valence. In contrast, the rims of some spinels in TS34 and spinel grain cores in two Vigarano type B inclusions have larger amounts of trivalent titanium. Spinels from TS34 have approximately equal amounts of divalent and trivalent vanadium. Based on experiments conducted on CAI-like compositions over a range of redox conditions, both clinopyroxene and spinel should be Ti+3-rich if they equilibrated with CAI liquids under near-solar oxygen fugacities. In igneous inclusions, the seeming paradox of high-valence spinels coexisting with low-valence clinopyroxene can be explained either by transient oxidizing conditions accompanying low-pressure evaporation or by equilibration of spinel with relict Ti+4-rich phases (e.g., perovskite) prior to or during melting. Ion probe analyses of large spinel grains in TS34 show that they are enriched in heavy Mg, with an average Δ25Mg of 4.25 ± 0.028‰, consistent with formation of the spinel from an evaporating liquid. Δ25Mg shows small, but significant, variation, both within individual spinels and between spinel and adjacent melilite hosts. The Δ25Mg data are most simply explained by the low-pressure evaporation model, but this model has difficulty explaining the high Ti+4 concentrations in spinel. © The Meteoritical Society, 2013.
  • Sakaguchi Isao, Sakamoto Naoya, Hashiguchi Minako, Yurimoto Hisayoshi, Hishita Shunichi, Ohashi Naoki
    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 121 (1419) 956 - 959 1882-0743 2013/11 [Refereed][Not invited]
  • Hisayoshi Yurimoto
    AIP Conference Proceedings 1484 139 - 141 1551-7616|0094-243X 2012/12 [Refereed][Not invited]
     
    Preliminary examinations of particles on asteroid Itokawa surface returned by Hayabusa mission have been completed by X-ray CT analysis, X-ray diffraction analysis, petrology, mineral chemistry, oxygen isotope analysis, trace element analysis and noble gas analysis. The laboratory characterization of Itokawa particles certified that Itokawa was composed of similar materials of ordinary chondrites. This is the first direct link showing that Stype asteroids is one of the sources of the ordinary chondrites, which are the most abundant meteorite species fallen into the Earth. © 2012 American Institute of Physics.
  • Characterization of Bone Mineralization in a Rat Model of Chronic Kidney Disease
    Kimura-Suda Hiromi, Kanazawa Kyosuke, Kobayashi Sachio, Kuwahara Mieko, Ito Teppei, Sakamoto Naoya, Kajiwara Makoto, Yamato Hideyuki, Ijiro Kuniharu, Yurimoto Hisayoshi
    JOURNAL OF BONE AND MINERAL RESEARCH 28 0884-0431 2013/02 [Refereed][Not invited]
  • Changkun Park, Changkun Park, Shigeyuki Wakaki, Naoya Sakamoto, Sachio Kobayashi, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 47 (12) 2070 - 2083 1086-9379 2012/12 [Refereed][Not invited]
     
    High-precision isotope imaging analyses of reversely zoned melilite crystals in the gehlenitic mantle of Type A CAI ON01 of the Allende carbonaceous chondrite reveal that there are four types of oxygen isotopic distributions within melilite single crystals: (1) uniform depletion of 16O (δ18O≈-10‰), (2) uniform enrichment of 16O (δ18O≈-40‰), (3) variations in isotopic composition from 16O-poor core to 16O-rich rim (δ18O≈-10‰ to -30‰, -20‰ to -45‰, and -10‰ to -35‰) with decreasing åkermanite content, and (4) 16O-poor composition (δ18O≥-10‰) along the crystal rim. Hibonite, spinel, and perovskite grains are 16O-rich (δ18O≈-45‰), and adjoin 16O-poor melilites. Gas-solid or gas-melt isotope exchange in the nebula is inconsistent with both the distinct oxygen isotopic compositions among the minerals and the reverse zoning of melilite. Fluid-rock interaction on the parent body resulted in 16O-poor compositions of limited areas near holes, cracks, or secondary phases, such as anorthite or grossular. We conclude that reversely zoned melilites mostly preserve the primary oxygen isotopic composition of either 16O-enriched or 16O-depleted gas from which they were condensed. The correlation between oxygen isotopic composition and åkermanite content may indicate that oxygen isotopes of the solar nebula gas changed from 16O-poor to 16O-rich during melilite crystal growth. We suggest that the radial excursions of the inner edge of the protoplanetary disk gas simultaneously resulted in both the reverse zoning and oxygen isotopic variation of melilite, due to mixing of 16O-poor disk gas and 16O-rich coronal gas. Gas condensates aggregated to form the gehlenite mantle of the Type A CAI ON01. © 2012 The Meteoritical Society.
  • Juri Katayama, Shoichi Itoh, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 47 (12) 2094 - 2106 1086-9379 2012/12 [Refereed][Not invited]
     
    The oxygen isotopic microdistributions within melilite measured using in situ secondary ion mass spectrometry correspond to the chemical zoning profiles in single melilite crystals of a fluffy type A Ca-Al-rich inclusions (CAIs) of reduced CV3 Vigarano meteorite. The melilite crystals show chemical reverse zoning within an individual single crystal from the åkermanite-rich core to the åkermanite-poor rim. The composition changes continuously with the crystal growth. The zoning structures suggest that the melilite grew in a hot nebular gas by condensation with decreasing pressure. The oxygen isotopic composition of melilite also changes continuously from 16O-poor to 16O-rich with the crystal growth. These observations suggest that the melilite condensation proceeded with change consistent with an astrophysical setting around the inner edge of a protoplanetary disk where both 16O-rich solar coronal gas and 16O-poor dense protoplanetary disk gas could coexist. Fluffy type A CAIs could have been formed around the inner edge of the protoplanetary disk surrounding the early sun. © 2012 The Meteoritical Society.
  • Noriyuki Kawasaki, Naoya Sakamoto, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 47 (12) 2084 - 2093 1086-9379 2012/12 [Refereed][Not invited]
     
    Different oxygen isotopic reservoirs have been recognized in the early solar system. Fluffy type A Ca-Al-rich inclusions (CAIs) are believed to be direct condensates from a solar nebular gas, and therefore, have acquired oxygen from the solar nebula. Oxygen isotopic and chemical compositions of melilite crystals in a type A CAI from Efremovka CV3 chondrite were measured to reveal the temporal variation in oxygen isotopic composition of surrounding nebular gas during CAI formation. The CAI is constructed of two domains, each of which has a core-mantle structure. Reversely zoned melilite crystals were observed in both domains. Melilite crystals in one domain have a homogeneous 16O-poor composition on the carbonaceous chondrite anhydrous mineral (CCAM) line of δ18O=5-10‰, which suggests that the domain was formed in a 16O-poor oxygen isotope reservoir of the solar nebula. In contrast, melilite crystals in the other domain have continuous variations in oxygen isotopic composition from 16O-rich (δ18O=-40‰) to 16O-poor (δ18O=0‰) along the CCAM line. The oxygen isotopic composition tends to be more 16O-rich toward the domain rim, which suggests that the domain was formed in a variable oxygen isotope reservoir of the solar nebula. Each domain of the type A CAI has grown in distinct oxygen isotope reservoir of the solar nebula. After the domain formation, domains were accumulated together in the solar nebula to form a type A CAI. © 2012 The Meteoritical Society.
  • S. Wakaki, S. Itoh, T. Tanaka, H. Yurimoto
    Geochimica et Cosmochimica Acta 102 261 - 279 00167037 2013/02 [Refereed][Not invited]
     
    We report the petrology, trace element abundances and oxygen isotopic characteristics of a compound CAI-chondrule object, WI-025, found in the Allende CV3 chondrite. The WI-025 is an irregularly shaped inclusion consisting of three texturally and chemically distinct portions: the interior portion, the igneous rim and the intermediate zone located between these two portions. The interior portion consists of anorthite, spinel, olivine and Al-bearing low-Ca pyroxene. The major element chemistry of the interior portion corresponds to that of Al-rich chondrules and is of intermediate character between fine-grained spinel-rich CAIs and ferromagnesian chondrules. The interior portion has abundant 16O-rich spinel (Δ17O=-14.2 to -24.7) and displays a group II CAI-like REE composition. These observations indicate that the interior portion contains a CAI component formed by fractional condensation. The major and trace element chemistry of the interior portion indicate that the CAI had subsequently assimilated chondrule materials through partial melting. The maximum heating temperature of the partial melting is estimated at approximately 1400°C, similar to the maximum heating temperature of Type-B CAIs. The oxygen isotopic compositions of the olivine and low-Ca pyroxene (Δ17O=-6.3) in the interior portion indicate that the partial melting and chondrule assimilation took place under a moderately 16O-poor nebular gas. The igneous rim is texturally and chemically similar to ferromagnesian chondrules and entirely surrounds the interior portion. The oxygen isotopic compositions of the olivine and low-Ca pyroxene in the igneous rim are indistinguishable from those of the interior olivine and Al-bearing low-Ca pyroxenes. These observations indicate that a chondrule material, which was melted in the same nebular gas as the interior portion, was accreted to the interior portion. The intermediate zone represents a reaction zone accompanying the igneous rim formation. The formation history of WI-025 can be summarized by the following processes: (1) original CAI formation, (2) partial melting and chondrule assimilation, (3) igneous rim formation and (4) secondary alteration on the parent body. © 2012 Elsevier Ltd.
  • Motai S, Nagai T, Sowa K, Watanabe T, Sakamoto N, Yurimoto H, Kawano J
    Journal of structural biology 180 (3) 389 - 393 1047-8477|1095-8657 2012/12 [Refereed][Not invited]
  • Hongzhan Fei, Chamathni Hegoda, Daisuke Yamazaki, Michael Wiedenbeck, Hisayoshi Yurimoto, Svyatoslav Shcheka, Tomoo Katsura
    Earth and Planetary Science Letters 345-348 95 - 103 0012-821X 2012/09 [Refereed][Not invited]
     
    Silicon self-diffusion coefficients (D Si) in dry synthetic forsterite single crystals were measured at temperatures of 1600 and 1800K, from ambient pressure up to 13GPa using an ambient pressure furnace and Kawai-type multi-anvil apparatus. The water contents in the samples were carefully controlled at <1μg/g. Diffusion profiles were obtained by secondary ion mass spectrometry (SIMS) in depth profiling mode. Small negative pressure dependence of D Si is determined with an activation volume of 1.7±0.4cm 3/mol. The activation energy is found to be 410±30kJ/mol. LogD Si values (D Si in m 2/s) at 1600 and 1800K at ambient pressure are determined to be -19.7±0.4 and -18.1±0.3, respectively. These values are ~2.4 orders of magnitude higher than those reported by Jaoul et al. (1981). We speculate that their low D Si might reflect the effects of a horizontal migration of the isotopically enriched thin films applied on the sample surfaces, which may inhibit diffusion into the substrate during annealing. Our results for D Si resolve the inconsistency between D Si measured in diffusion experiments and those deduced from creep rates measured in deformation experiments. © 2012 Elsevier B.V.
  • Naoya Sakamoto, Satoshi Aoyama, Shoji Kawahito, Shoji Kawahito, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Japanese Journal of Applied Physics 51 (7,Issue 1) 1 - 76701 0021-4922|1347-4065 2012/07 [Refereed][Not invited]
     
    We designed a new type of stacked complementary metal-oxide-semiconductor active pixel sensor (SCAPS) for charged particles with real-time readout and single-ion detection capabilities. Here we present the characteristics of a new imager, SCAPS-II, which implements a newly devised pixel structure of 504 × 504 pixels for high sensitivity and a noise-reduction mechanism with analog accumulation capabilities inside the column readout circuits. The sensitivity for ions was estimated to be 150 μV/ion under 10 keV Si+ ion irradiation, which is 5 times greater than that of conventional SCAPS. The noise floor was at the 3 ion level without the noise-reduction mechanism at a frame rate of 0.16 s/frame. The noise reduction mechanism reduced the noise to the 1.7 ion level at 0.3 s/frame with 13 samplings. A combination of the noise-reduction mechanism and a multiple-frame-averaging technique achieved a noise level of 0.3 ions. Single-ion detectability was demonstrated using a combination of the noise-reduction mechanism and the multiple-frame-averaging technique that reduced the noise to the 0.3 ion level with 13 samplings, employing an integration circuit and 50-frame averaging at 14.4 s/frame. © 2012 The Japan Society of Applied Physics.
  • Shingo Ebata, Shingo Ebata, Morio Ishihara, Kiichiro Uchino, Satoru Itose, Miyuki Matsuya, Masato Kudo, Ken Ichi Bajo, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Surface and Interface Analysis 44 (6) 635 - 640 1096-9918|0142-2421 2012/06 [Refereed][Not invited]
     
    We have developed a new nano-beam time-of-flight secondary neutral mass spectrometry system: laser ionization mass nanoscope or LIMAS. The primary ion beam column was equipped with a Ga liquid metal ion source and aberration correction optics. The primary ion beam was down to 40 nm in diameter under a current of 100 pA with an energy of 20 keV. The sputtered particles were post-ionized under non-resonance mode by a femtosecond laser. The post-ionized ions were introduced into a multi-turn mass spectrometer. A mass resolution of up to 40 000 was achieved. The vacuum of the sample chamber was maintained under an ultrahigh vacuum of 2×10 -8 Pa. This instrument would be effective for ultrahigh sensitive analysis of nanosized particles such as return samples from asteroids, comets, and planets. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.
  • Madhusoodhan Satish-Kumar, Hisayoshi Yurimoto, Shoichi Itoh, Bernardo Cesare
    Contributions to Mineralogy and Petrology 162 (4) 821 - 834 1432-0967|0010-7999 2011/10 [Refereed][Not invited]
     
    High-spatial resolution carbon isotope analyses of natural graphite using secondary ion mass spectrometry (SIMS), together with conventional mass spectrometry techniques, demonstrate isotopic heterogeneity within single graphite crystals precipitated from a partially melted metamorphic rock. SIMS 13C/12C measurements were calibrated using an internal graphite standard previously analyzed by conventional isotope ratio mass spectrometry, which gave a reproducibility of 0.3‰ (1σ) at a spatial resolution of 2-3 μm. This resolution helped to identify an unusual carbon isotope distribution in a single graphite crystal from a metapelitic leucosome, showing remarkable core to rim variations with sharp δ13C steps up to 10‰. The results suggest that the graphite crystal grew from one edge to other forming layers perpendicular to the c-axis. The sharp isotopic steps indicate the presence of disequilibrium carbon isotope zoning in graphite and points to the possible existence of carbon isotope sector zoning. Intra-crystalline carbon isotope disequilibrium in graphite is believed to have resulted from the difference in diffusivity between 12C and 13C in the growth medium to the interface of graphite precipitation in different growth sectors. © 2011 Springer-Verlag.
  • Nagao K, Okazaki R, Nakamura T, Miura YN, Osawa T, Bajo K, Matsuda S, Ebihara M, Ireland TR, Kitajima F, Naraoka H, Noguchi T, Tsuchiyama A, Yurimoto H, Zolensky ME, Uesugi M, Shirai K, Abe M, Yada T, Ishibashi Y, Fujimura A, Mukai T, Ueno M, Okada T, Yoshikawa M, Kawaguchi J
    Science (New York, N.Y.) 333 (6046) 1128 - 1131 0036-8075|1095-9203 2011/08 [Refereed][Not invited]
  • H. Naraoka, H. Mita, K. Hamase, M. Mita, H. Yabuta, K. Saito, K. Fukushima, F. Kitajima, S. A. Sandford, T. Nakamura, T. Noguchi, R. Okazaki, K. Nagao, M. Ebihara, H. Yurimoto, A. Tsuchiyama, M. Abe, K. Shirai, M. Ueno, T. Yada, Y. Ishibashi, T. Okada, A. Fujimura, T. Mukai, M. Yoshikawa, J. Kawaguchi
    Geochemical Journal 46 (1) 61 - 72 00167002 2012/12 [Refereed][Not invited]
     
    Microparticles recovered from the Asteroid 25143 Itokawa surface by the Hayabusa mission have been examined for the occurrence of soluble organic compounds. After five individual particles (∼50 to 100 μm in diameter) were rinsed with organic solvents on a diamond plate, two extracts were hydrolyzed with hydrochloric acid for amino acid analysis (AAA), and three extracts were combined for time of flight-secondary ion mass spectrometry (ToF-SIMS) to look for other organic compounds, including polycyclic aromatic hydrocarbons. The organic compounds detected by both methods have the same concentrations as those in blank levels, indicating that indigenous organic compounds are not found in this study. Based on the sensitivities of AAA and ToF-SIMS with the reference sample analyses, the concentrations of indigenous organics in the samples are below part-per-million (ppm), if present. Copyright © 2012 by The Geochemical Society of Japan.
  • Yurimoto H, Abe K, Abe M, Ebihara M, Fujimura A, Hashiguchi M, Hashizume K, Ireland TR, Itoh S, Katayama J, Kato C, Kawaguchi J, Kawasaki N, Kitajima F, Kobayashi S, Meike T, Mukai T, Nagao K, Nakamura T, Naraoka H, Noguchi T, Okazaki R, Park C, Sakamoto N, Seto Y, Takei M, Tsuchiyama A, Uesugi M, Wakaki S, Yada T, Yamamoto K, Yoshikawa M, Zolensky ME
    Science (New York, N.Y.) 333 (6046) 1116 - 1119 0036-8075|1095-9203 2011/08 [Refereed][Not invited]
  • Tsuchiyama A, Uesugi M, Matsushima T, Michikami T, Kadono T, Nakamura T, Uesugi K, Nakano T, Sandford SA, Noguchi R, Matsumoto T, Matsuno J, Nagano T, Imai Y, Takeuchi A, Suzuki Y, Ogami T, Katagiri J, Ebihara M, Ireland TR, Kitajima F, Nagao K, Naraoka H, Noguchi T, Okazaki R, Yurimoto H, Zolensky ME, Mukai T, Abe M, Yada T, Fujimura A, Yoshikawa M, Kawaguchi J
    Science (New York, N.Y.) 333 (6046) 1125 - 1128 0036-8075|1095-9203 2011/08 [Refereed][Not invited]
  • Ritsuro Miyawaki, Hidehiko Shimazaki, Hidehiko Shimazaki, Masako Shigeoka, Kazumi Yokoyama, Satoshi Matsubara, Hisayoshi Yurimoto
    European Journal of Mineralogy 23 (3) 467 - 473 0935-1221 2011/06 [Refereed][Not invited]
     
    Yangzhumingite, ideally KMg2.5Si4O10F2, occurs as subhedral to euhedral platy crystals up to ca. 0.5 mm across in metamorphosed carbonate rock from Bayan Obo, Inner Mongolia, China. It is associated with dolomite, calcite, tremolite, norbergite and huanghoite-(Ce) with minor phlogopite, barite, bastnäsite-(Ce), parisite-(Ce), and fluorite. Yangzhumingite is transparent and colorless with white streak and pearly luster. It is optically biaxial (-), n = 1.532-1.537 (589 nm), and 2V = 5-10°. The hardness is 3 on Mohs' scale (measured on a synthetic equivalent). It has a monoclinic unit cell with a = 5.249(4), b = 9.095(5), c = 10.142(5)Å , β = 99.96(6)°, V = 476.9(5)Å3, Z = 2, space group C2/m, and Dcalc. = 2.807 g/cm3. The five strongest lines in the powder XRD pattern are [d(Å ), I/I0, hkl]: (10.03, 95, 001); (3.37, 48, 022), (2.90, 49, 113), (2.59, 67, 131 200) and (2.41, 100, 132 201). The mean of 15 electron microprobe analyses and SIMS analysis for Li lead to the empirical formula (K0.70Li0.30Na0.01)(Mg2.48Fe 0.06) (Si3.96Al0.03)O10[F 1.92(OH)0.08] on the basis of 12 anions with (F + OH) = 2. Yangzhumingite is a member of the mica group (Nickel-Strunz grouping 9.EC.10), and it represents the Mg-dominant analogue of montdorite. © 2011 E. Schweizerbart'sche Verlagsbuchhandlung.
  • James P. Greenwood, Shoichi Itoh, Naoya Sakamoto, Paul Warren, Lawrence Taylor, Hisayoshi Yurimoto
    Nature Geoscience 4 (2) 79 - 82 1752-0894|1752-0908 2011/02 [Refereed][Not invited]
     
    Water plays a critical role in the evolution of planetary bodies 1, and determination of the amount and sources of lunar water has profound implications for our understanding of the history of the Earth-Moon system. During the Apollo programme, the lunar samples were found to be devoid of indigenous water2,3. The severe depletion of volatiles, including water, in lunar rock samples4 has long been seen as strong support for the theory that the Moon formed during a giant impact event5. Water has now been identified in lunar volcanic glasses6 and apatite7-9, but the sources of water to the Moon have not been determined. Here we report ion microprobe measurements of water and hydrogen isotopes in the hydrous mineral apatite, derived from crystalline lunar mare basalts and highlands rocks collected during the Apollo missions. We find significant water in apatite from both mare and highlands rocks, indicating a role for water during all phases of the Moon's magmatic history. Variations of hydrogen isotope ratios in apatite suggest sources for water in lunar rocks could come from the lunar mantle, solar wind protons and comets. We conclude that a significant delivery of cometary water to the Earth-Moon system occurred shortly after the Moon-forming impact. © 2011 Macmillan Publishers Limited. All rights reserved.
  • C. Park, S. Wakaki, H. Yurimoto
    Surface and Interface Analysis 44 (6) 678 - 681 01422421 2012/06 [Refereed][Not invited]
     
    Ca-Al-rich inclusions (CAIs) are thought to be the oldest rocks in the solar system. CAIs have oxygen isotope heterogeneities on inter-mineral and intra-mineral scales that provide information about environments of the early solar system. We studied a type A CAI from the Allende meteorite, showing a core-mantle structure. Reversely zoned melilite found in the mantle was identified by a combination of energy dispersive X-ray spectrometer and electron back-scattered diffraction techniques. For investigation of oxygen isotopic variations of reversely zoned melilite, we developed a high-precision secondary ion mass spectrometry method that achieves to ∼1‰ (1σ) under the spatial resolution of ∼3 μm in diameter. Oxygen isotopic composition of core melilite is uniformly 16O-poor (δ 17, 18O ≈ -5 to 0‰), whereas mantle melilite varies widely from 16O-poor (δ 17, 18O ≈ -5‰) to rich (δ 17, 18O ≈ -45‰) at the micrometer scale. The variation possibly suggests that the oxygen isotopic composition of solar nebular gas was changed from 16O-poor to 16O-rich at the last stage of the CAI formation. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.
  • Junshan Xu, Junshan Xu, Junshan Xu, Daisuke Yamazaki, Tomoo Katsura, Tomoo Katsura, Xiaoping Wu, Patrick Remmert, Hisayoshi Yurimoto, Sumit Chakraborty
    Journal of Geophysical Research: Solid Earth 116 (B12) 12205 - 12205 0148-0227|2156-2202|2169-9356 2011/01 [Refereed][Not invited]
     
    Si and Mg self-diffusion coefficients were measured simultaneously in single crystals of MgSiO3 perovskite under lower mantle conditions. There is little difference in Si volume diffusivity measured directly using single crystals (this study) and those retrieved from experiments with polycrystals (earlier studies). This agreement between studies establishes the reliability of Si diffusion coefficients measured in perovskite. Within the uncertainties of our measurements, no anisotropy in the diffusion of either Si or Mg could be resolved. Diffusion of Si and Mg in perovskite are described by an Arrhenius equation, D=D0 exp (-H/RT) at 25GPa, with D 0=5.10×10-11m2/s for Si and 4.99×10-11m2/s for Mg, H=308kJ/mol for Si, and 305kJ/mol for Mg. Mg diffusivity in MgSiO3 perovskite is distinctly lower than those measured in olivine, wadsleyite, and ringwoodite. We find that Mg has very similar diffusivity to Si in perovskite. As a consequence, the rheological properties of the lower mantle may be controlled by the coupled motion of Si and Mg. A point defect-based model is discussed that may account for the diffusion behavior of Si and Mg in MgSiO3 perovskite. Our data indicate that, within realistic ranges of temperature, grain size, and state of stress, both diffusion creep as well as dislocation creep may be observed in the lower mantle. Copyright 2011 by the American Geophysical Union.
  • Toru Inoue, Tomoyuki Wada, Rumi Sasaki, Hisayoshi Yurimoto
    Physics of the Earth and Planetary Interiors 183 (1-2) 245 - 251 0031-9201 2010/11 [Refereed][Not invited]
     
    We have conducted H2O partitioning experiments between wadsleyite and ringwoodite and between ringwoodite and perovskite at 1673K and 1873K, respectively. These experiments were performed in order to constrain the relative distribution of H2O in the upper mantle, the mantle transition zone, and the lower mantle. We successfully synthesized coexisting mineral assemblages of wadsleyite-ringwoodite and ringwoodite-perovskite that were large enough to measure the H2O contents by secondary ion mass spectrometry (SIMS). Combining our previous H2O partitioning data (Chen et al., 2002) with the present results, the determined water partitioning between olivine, wadsleyite, ringwoodite, and perovskite under H2O-rich fluid saturated conditions are 6:30:15:1, respectively. Because the maximum H2O storage capacity in wadsleyite is ∼3.3wt% (e.g. Inoue et al., 1995), the possible maximum H2O storage capacity in the olivine high-pressure polymorphs are as follows: ∼0.7wt% in olivine (upper mantle just above 410km depth), ∼3.3wt% in wadsleyite (410-520km depth), ∼1.7wt% in ringwoodite (520-660km depth), and ∼0.1wt% in perovskite (lower mantle). If we assume ∼0.2wt% of the H2O content in wadsleyite in the mantle transition zone estimated by recent electrical conductivity measurements (e.g. Dai and Karato, 2009), the estimated H2O contents throughout the mantle are as follows; ∼0.04wt% in olivine (upper mantle just above 410km depth), ∼0.2wt% in wadsleyite (410-520km depth), ∼0.1wt% in ringwoodite (520-660km depth) and ∼0.007wt% in perovskite (lower mantle). Thus, the mantle transition zone should contain a large water reservoir in the Earth's mantle compared to the upper mantle and the lower mantle. © 2010 Elsevier B.V.
  • Morio Ishihara, Shingo Ebata, Kousuke Kumondai, Ryo Mibuka, Kiichiro Uchino, Hisayoshi Yurimoto
    Surface and Interface Analysis 42 (10/11) 1598 - 1602 1096-9918|0142-2421 2010/10 [Refereed][Not invited]
     
    The performance of a newly developed TOF-SIMS System with a femtosecond laser postionization and a multiturn mass spectrometer was investigated in linear mode. This system would be very effective for analyzing valuable material such as space samples. By using postionization the secondary ion signals of Ag were increased (up to 100 times), compared with the conventional TOF-SIMS experiments. The laser power dependence on the signal intensities was also investigated and it was confirmed that the signal intensities reached specific values above the specific laser power. Lateral resolution of the elemental map was calculated to be about 40 nm. © 2010 John Wiley & Sons, Ltd.
  • M. Ebihara, S. Sekimoto, N. Shirai, Y. Hamajima, M. Yamamoto, K. Kumagai, Y. Oura, T. R. Ireland, F. Kitajima, K. Nagao, T. Nakamura, H. Naraoka, T. Noguchi, R. Okazaki, A. Tsuchiyama, M. Uesugi, H. Yurimoto, M. E. Zolensky, M. Abe, A. Fujimura, T. Mukai, Y. Yada
    Science 333 (6046) 1119 - 1121 00368075 2011/08 [Refereed][Not invited]
     
    A single grain (~3 micrograms) returned by the Hayabusa spacecraft was analyzed by neutron activation analysis. This grain is mainly composed of olivine with minor amounts of plagioclase, troilite, and metal. Our results establish that the Itokawa sample has similar chemical characteristics (iron/scandium and nickel/cobalt ratios) to chondrites, confirming that this grain is extraterrestrial in origin and has primitive chemical compositions. Estimated iridium/nickel and iridium/cobalt ratios for metal in the Itokawa samples are about five times lower than CI carbonaceous chondrite values. A similar depletion of iridium was observed in chondrule metals of ordinary chondrites. These metals must have condensed from the nebular where refractory siderophile elements already condensed and were segregated.
  • Alexander N. Krot, Kazuhide Nagashima, Miwa Yoshitake, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 74 (7) 2190 - 2211 0016-7037 2010/04 [Refereed][Not invited]
     
    It has been recently suggested that (1) CH chondrites and the CBb/CH-like chondrite Isheyevo contain two populations of chondrules formed by different processes: (i) magnesian non-porphyritic (cryptocrystalline and barred) chondrules, which are similar to those in the CB chondrites and formed in an impact-generated plume of melt and gas resulted from large-scale asteroidal collision, and (ii) porphyritic chondrules formed by melting of solid precursors in the solar nebula. (2) Porphyritic chondrules in Isheyevo and CH chondrites are different from porphyritic chondrules in other carbonaceous chondrites (Krot et al., 2005, 2008a,b). In order to test these hypotheses, we measured in situ oxygen isotopic compositions of porphyritic (magnesian, Type I and ferroan, Type II) and non-porphyritic (magnesian and ferroan cryptocrystalline) chondrules from Isheyevo and CBb chondrites MAC 02675 and QUE 94627, paired with QUE 94611, using a Cameca ims-1280 ion microprobe. On a three-isotope oxygen diagram (δ17O vs. δ18O), compositions of chondrules measured follow approximately slope-1 line. Data for 19 magnesian cryptocrystalline chondrules from Isheyevo, 24 magnesian cryptocrystalline chondrules and 6 magnesian cryptocrystalline silicate inclusions inside chemically-zoned Fe,Ni-metal condensates from CBb chondrites have nearly identical compositions: Δ17O = -2.2 ± 0.9‰, -2.3 ± 0.6‰ and -2.2 ± 1.0‰ (2σ), respectively. These observations and isotopically light magnesium compositions of cryptocrystalline magnesian chondrules in CBb chondrites (Gounelle et al., 2007) are consistent with their single-stage origin, possibly as gas-melt condensates in an impact-generated plume. In contrast, Δ17O values for 11 Type I and 9 Type II chondrules from Isheyevo range from -5‰ to +4‰ and from -17‰ to +3‰, respectively. In contrast to typical chondrules from carbonaceous chondrites, seven out of 11 Type I chondrules from Isheyevo plot above the terrestrial fractionation line. We conclude that (i) porphyritic chondrules in Isheyevo belong to a unique population of objects, suggesting formation either in a different nebular region or at a different time than chondrules from other carbonaceous chondrites; (ii) Isheyevo, CB and CH chondrites are genetically related meteorites: they contain non-porphyritic chondrules produced during the same highly-energetic event, probably large-scale asteroidal collision; (iii) the differences in mineralogy, petrography, chemical and whole-rock oxygen isotopic compositions between CH and CB chondrites are due to various proportions of the nebular and the impact-produced materials. © 2010 Elsevier Ltd. All rights reserved.
  • D/H of Lunar water: Implications for the origin of the Earth's water
    Greenwood James P., Itoh Shoichi, Sakamoto Naoya, Warren Paul H., Taylor Lawrence A., Yurimoto Hisayoshi
    GEOCHIMICA ET COSMOCHIMICA ACTA 74 (12) A354  0016-7037 2010/06 [Refereed][Not invited]
  • Kumiko Fujimoto, Shoichi Itoh, Shingo Ebata, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochemical Journal 43 (6) 11 - 15 0016-7002|1880-5973 2009/12 [Refereed][Not invited]
     
    Oxygen isotopic compositions of metal grains in a noble-gas-rich chondrite, NWA 801 CR2, have been determined by secondary ion mass spectrometry. The results show bimodal distribution on δ17O histogram with peaks of δ17O = 2.3 and -35.0%c. The 16O-rich peak seems to be due to stellar wind from the protosun. The 16O enrichment is comparable with the most 16O-rich value from chondrite constituents. Difference of oxygen isotopic composition of stellar wind between protosun and the present sun implies how self-pollution by planetary embryos during the planet formation epoch have occurred and whether the present solar photosphere preserves the representative composition of the solar system. Copyright © 2009 by The Geochemical Society of Japan.
  • K. Yamamoto, N. Sakamoto, H. Yurimoto
    Surface and Interface Analysis 42 (10-11) 1603 - 1605 01422421 2010/10 [Refereed][Not invited]
     
    By analyzing the noise characteristics of a stacked CMOS-type active pixel sensor (SCAPS), we developed a noise reduction method. We also developed a multiple frame-averaging method based on a correlated double sampling (CDS) between averaged frames, which use the multiple frames collected by nondestructive readout of signals before and after ion irradiation. This method suppresses SCAPS read noise to 11 μV, corresponding to 0.37 ions. Ion transfer and noise performance were evaluated by above method, leading to the confirmation of noise suppression below the level of single ion detection and the expansion of the dynamic range of SCAPS to 102 dB. © 2010 John Wiley & Sons, Ltd.
  • Shingo Ebata, Timothy J. Fagan, Hisayoshi Yurimoto
    Applied Surface Science 255 (4) 1468 - 1471 0169-4332 2008/12 [Refereed][Not invited]
     
    An isotope ratio imaging technique using the HokuDai isotope microscope system has been applied to in situ survey for presolar grains in the type-3 enstatite chondrite ALHA81189. Rastered and static ion beam were used for primary beam. Lateral resolution of the isotope image was achieved to be 0.4 μm for static ion beam mode and to be 0.6 μm for rastered ion beam mode. As a result, the abundances of presolar grains are 150-200% larger under the static ion beam mode than under the rastered ion beam mode. Development of image processing introducing isotopography of 32S-, 24Mg16O- and 56Fe- succeeded to increase efficiency of presolar grain characterization. Using the static ion beam and introducing appropriate isotopography were very useful methods of in situ characterization of presolar grains in meteorites. © 2008 Elsevier B.V. All rights reserved.
  • Shoichi Itoh, Kentaro Makide, Hisayoshi Yurimoto
    Applied Surface Science 255 (4) 1476 - 1478 0169-4332 2008/12 [Refereed][Not invited]
     
    High precision Mg isotope measurements have been performed to determine radiogenic 26Mg of CAI minerals by secondary ion mass spectrometry using Faraday cup multi-collection system. Terrestrial samples of spinel and augite, and synthetic glasses of melilite and fassaite, were prepared to correct instrumental mass fractionation. Reproducibility of Mg isotope measurements for each standard were limited to ∼0.4‰ (2σ). On the other hand, the standard errors for one spot are ∼0.05‰ (2σ). The poor reproducibility resulted from variations of instrumental mass fractionation among individual measurement spots. We propose novel calculation method of radiogenic 26Mg considering instrumental and natural mass fractionation for each mineral. The overall measurement error of radiogenic 26Mg of the minerals can be calculated less than 0.2‰ (2σ). This provides that the time resolution of early solar system chronometer was improved up to 100K year for ∼20 μm scale objects formed in the early solar system. © 2008 Elsevier B.V.
  • Naoya Sakamoto, Shoichi Itoh, Hisayoshi Yurimoto
    Applied Surface Science 255 (4) 1458 - 1460 0169-4332 2008/12 [Refereed][Not invited]
     
    We report a discovery of a chemically and isotopically unique material distributed ubiquitously in fine-grained matrix of a primitive carbonaceous chondrite Acfer 094. The observations were made in situ using a novel high precision imaging technique adopted direct-imaging method. The material is extremely enriched in heavy oxygen isotopes of 17O and 18O of +18% relative to the Earth's ocean while previously reported variation of oxygen isotopes is as large as a range from -8% to 0%. Based on the unique chemical composition of the material, the abundance of the material in the meteorite matrix is calculated to be 94 ± 20 ppm (σ) by volume using elemental mapping with a 7 μm2 spatial resolution by FE-SEM-EDS on the meteorite thin section. The average size of identified materials is 5 μm × 5 μm × 5 μm. Therefore, isotope imaging capability over 500 μm × 500 μm area with micron resolution and an isotopic ratio precision of 1% is required to investigate about the presence of such material. © 2008 Elsevier B.V. All rights reserved.
  • Yurimoto H.
    Japanese Journal of Clinical Chemistry 38 (3) 272 - 279 2009 [Refereed][Not invited]
  • T. Tsuji, T. Tsuji, T. Tawara, T. Tawara, R. Tanuma, R. Tanuma, Y. Yonezawa, Y. Yonezawa, N. Iwamuro, K. Kosaka, H. Yurimoto, S. Kobayashi, H. Matsuhata, K. Fukuda, O. Okumura, K. Arai
    Materials Science Forum 645-648 913 - 916 02555476 2010/01 [Refereed][Not invited]
     
    The authors fabricated pn diodes with Al+ implantation in p-type epitaxial layers, and investigated the influence of the implantation dose on reverse leakage currents. Only in the highest dose with the Al concentration of 2×1020cm-3, more than 90% of the devices showed high leakage currents above 10-4A at the maximum electric field of 3MV/cm. In such devices, almost all of the emissive spots corresponded to threading screw dislocations (TSDs) by the analysis of emission microscopy and X-ray topography. These TSDs were defined as killer defects with the estimated density of 500cm-2 in the case of the highest dose. The emissions were supposed to be due to microplasmas, since the spectra of the emissions were different from those of heat radiation. Condensation of Al atoms, nitrogen atoms and DI defects were excluded as the origin of the emissions by secondary ion mass spectrometry and low temperature photoluminescence analyses. © (2010) Trans Tech Publications, Switzerland.
  • A. N. Krot, Y. Amelin, P. Bland, F. J. Ciesla, J. Connelly, J. Connelly, A. M. Davis, G. R. Huss, I. D. Hutcheon, K. Makide, K. Nagashima, L. E. Nyquist, S. S. Russell, E. R D Scott, K. Thrane, H. Yurimoto, Q. Z. Yin
    Geochimica et Cosmochimica Acta 73 (17) 4963 - 4997 00167037 2009/09 [Refereed][Not invited]
     
    Mineralogical observations, chemical and oxygen-isotope compositions, absolute 207Pb-206Pb ages and short-lived isotope systematics (7Be-7Li, 10Be-10B, 26Al-26Mg, 36Cl-36S, 41Ca-41K, 53Mn-53Cr, 60Fe-60Ni, 182Hf-182W) of refractory inclusions [Ca,Al-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs)], chondrules and matrices from primitive (unmetamorphosed) chondrites are reviewed in an attempt to test (i) the x-wind model vs. the shock-wave model of the origin of chondritic components and (ii) irradiation vs. stellar origin of short-lived radionuclides. The data reviewed are consistent with an external, stellar origin for most short-lived radionuclides (7Be, 10Be, and 36Cl are important exceptions) and a shock-wave model for chondrule formation, and provide a sound basis for early Solar System chronology. They are inconsistent with the x-wind model for the origin of chondritic components and a local, irradiation origin of 26Al, 41Ca, and 53Mn. 10Be is heterogeneously distributed among CAIs, indicating its formation by local irradiation and precluding its use for the early solar system chronology. 41Ca-41K, and 60Fe-60Ni systematics are important for understanding the astrophysical setting of Solar System formation and origin of short-lived radionuclides, but so far have limited implications for the chronology of chondritic components. The chronological significance of oxygen-isotope compositions of chondritic components is limited. The following general picture of formation of chondritic components is inferred. CAIs and AOAs were the first solids formed in the solar nebula ∼4567-4568 Myr ago, possibly within a period of <0.1 Myr, when the Sun was an infalling (class 0) and evolved (class I) protostar. They formed during multiple transient heating events in nebular region(s) with high ambient temperature (at or above condensation temperature of forsterite), either throughout the inner protoplanetary disk (1-4 AU) or in a localized region near the proto-Sun (<0.1 AU), and were subsequently dispersed throughout the disk. Most CAIs and AOAs formed in the presence of an 16O-rich (Δ17O ∼ -24 ± 2‰) nebular gas. The 26Al-poor [(26Al/27Al)0 < 1 × 10-5], 16O-rich (Δ17O ∼ -24 ± 2‰) CAIs - FUN (fractionation and unidentified nuclear effects) CAIs in CV chondrites, platy hibonite crystals (PLACs) in CM chondrites, pyroxene-hibonite spherules in CM and CO chondrites, and the majority of grossite- and hibonite-rich CAIs in CH chondrites-may have formed prior to injection and/or homogenization of 26Al in the early Solar System. A small number of igneous CAIs in ordinary, enstatite and carbonaceous chondrites, and virtually all CAIs in CB chondrites are 16O-depleted (Δ17O > -10‰) and have (26Al/27Al)0 similar to those in chondrules (<1 × 10-5). These CAIs probably experienced melting during chondrule formation. Chondrules and most of the fine-grained matrix materials in primitive chondrites formed 1-4 Myr after CAIs, when the Sun was a classical (class II) and weak-lined T Tauri star (class III). These chondritic components formed during multiple transient heating events in regions with low ambient temperature (<1000 K) throughout the inner protoplanetary disk in the presence of 16O-poor (Δ17O > -5‰) nebular gas. The majority of chondrules within a chondrite group may have formed over a much shorter period of time (<0.5-1 Myr). Mineralogical and isotopic observations indicate that CAIs were present in the regions where chondrules formed and accreted (1-4 AU), indicating that CAIs were present in the disk as free-floating objects for at least 4 Myr. Many CAIs, however, were largely unaffected by chondrule melting, suggesting that chondrule-forming events experienced by a nebular region could have been small in scale and limited in number. Chondrules and metal grains in CB chondrites formed during a single-stage, highly-energetic event ∼4563 Myr ago, possibly from a gas-melt plume produced by collision between planetary embryos. © 2009 Elsevier Ltd. All rights reserved.
  • Hisayoshi Yurimoto
    Japanese Journal of Clinical Chemistry 38 272 - 279 03705633 2009/09 [Refereed][Not invited]
  • Masahiro Kudo, Retsu Oiwa, Hisayashi Yurimoto
    Applied Surface Science 255 803 - 804 01694332 2008/12 [Refereed][Not invited]
  • R. Mibuka, S. Hassaballa, K. Uchino, H. Yurimoto, R. Todokoro, K. Kumondai, M. Ishihara
    Applied Surface Science 255 (4) 1595 - 1598 01694332 2008/12 [Refereed][Not invited]
     
    Characteristics of the post-ionization using femto-second laser (fs laser) combined with the secondary ion mass spectrometer were investigated. For many metals, ionization saturations were confirmed for the laser power density of >2 × 1013 W/cm2. The characteristic curve of ionization of Ag against the laser power density suggests the occurrence of ionization through the multi-photon resonance excitation. Sensitivity increase after employing the fs laser post-ionization was manifested and a sputtered Cu signal from a minute circular area with a diameter of about 200 nm could be detected clearly. © 2008 Elsevier B.V. All rights reserved.
  • James P. Greenwood, Shoichi Itoh, Naoya Sakamoto, Edward P. Vicenzi, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geophysical Research Letters 35 (5) 5203  0094-8276|1944-8007 2008/03 [Refereed][Not invited]
     
    The high D/H of the Martian atmosphere (∼5-6 × terrestrial) is considered strong evidence for the loss of a Martian water to space. The timing and magnitude of the losss of water from Mars can be constrained by measurements of D/H in Martian meteorites. Previous studies of Martian meteorites have shown a large range in D/H, from terrestrial values to as high as the current Martian atmosphere. Here we show that the ancient (∼4 Ga) Mars meteorite ALH84001 has a D/H 4 × terrestrial and that the young (∼0.17 Ga) Shergotty meteorite has a D/H 5.6 × terrestrial. We also find that the young Los Angeles shergottite has zoning in D/H that can be correlated to igneous growth zoning, strongly suggesting assimilation of D-enriched waterir during igneous crystallization near the Martian surface. In contrast to previous studies, we find higher and less variable D/H ratios in these three meteorites. Our results suggest a two-stage evolution for Martian water - a significant early loss of water to space (prior to 3.9 Ga) followed by only modest loss to space in the last 4 billion years. The current Martian atmospheric D/H has remained essentially unchanged for the last 165 Ma. Copyright 2008 by the American Geophysical Union.
  • Yusuke Seto, Naoya Sakamoto, Kiyoshi Fujino, Takashi Kaito, Tetsuo Oikawa, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 72 (11) 2723 - 2734 0016-7037 2008/06 [Refereed][Not invited]
     
    We report the mineral compositions and micro-texture of the isotopically anomalous (δ17,18OSMOW ∼ +180‰) Fe-S-Ni-O material recently discovered in matrix of the primitive carbonaceous chondrite Acfer 094 [Sakamoto N., Seto Y., Itoh S., Kuramoto K., Fujino K., Nagashima K., Krot A. N. and Yurimoto H. (2007) Oxygen isotope evidence for remnants of the early solar system primordial water. Science 317, 231-233]. Synchrotron radiation X-ray diffraction and transmission electron microscopy studies indicate that this material consists of the symplectitically intergrown magnetite (Fe3O4) and pentlandite (Fe5.7Ni3.3S8) with magnetite/pentlandite volume ratio of ∼2.3. Magnetite forms column-shaped grains (10-30 nm in diameter and 100-200 nm in length); pentlandite occurs as worm-shaped grains or aggregates of grains 100-300 nm in size between magnetite crystals. Although both the X-ray diffraction and electron energy loss spectra support identification of iron oxide as magnetite, the electron diffraction patterns show that magnetite has a weak 3-fold superstructure, possibly due to ordering of vacancies. We infer that the isotopically anomalous symplectite formed by sulfurization and oxidization of metal grains either in the solar nebula or on an icy planetesimal. The intersite cation distribution of pentlandite suggests that timescale of oxidation was no longer than 1000 years. © 2008 Elsevier Ltd. All rights reserved.
  • Ebata Shingo, Yurimoto Hisayoshi
    ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 1016 412 - 414 0094-243X 2008 [Refereed][Not invited]
  • A. N. Krot, M. Chaussidon, H. Yurimoto, N. Sakamoto, K. Nagashima, I. D. Hutcheon, G. J. MacPherson
    Geochimica et Cosmochimica Acta 72 2534 - 2555 00167037 2008/05 [Refereed][Not invited]
     
    In situ oxygen isotopic measurements of primary and secondary minerals in Type C CAIs from the Allende CV3 chondrite reveal that the pattern of relative enrichments and depletions of 16O in the primary minerals within each individual CAI are similar to the patterns observed in Types A and B CAIs from the same meteorite. Spinel is consistently the most 16O-rich (Δ17O = -25‰ to -15‰), followed by Al,Ti-dioside (Δ17O = -20‰ to -5‰) and anorthite (Δ17O = -15‰ to 0‰). Melilite is the most 16O-depleted primary mineral (Δ17O = -5‰ to -3‰). We conclude that the original melting event that formed Type C CAIs occurred in a 16O-rich (Δ17O ≤ -20‰) nebular gas and they subsequently experienced oxygen isotopic exchange in a 16O-poor reservoir. At least three of these (ABC, TS26F1 and 93) experienced remelting at the time and place where chondrules were forming, trapping and partially assimilating 16O-poor chondrule fragments. The observation that the pyroxene is 16O-rich relative to the feldspar, even though the feldspar preceded it in the igneous crystallization sequence, disproves the class of CAI isotopic exchange models in which partial melting of a 16O-rich solid in a 16O-poor gas is followed by slow crystallization in that gas. For the typical (not associated with chondrule materials) Type C CAIs as well for as the Types A and B CAIs, the exchange that produced internal isotopic heterogeneity within each CAI must have occurred largely in the solid state. The secondary phases grossular, monticellite and forsterite commonly have similar oxygen isotopic compositions to the melilite and anorthite they replace, but in one case (CAI 160) grossular is 16O-enriched (Δ17O = -10‰ to -6‰) relative to melilite (Δ17O = -5‰ to -3‰), meaning that the melilite and anorthite must have exchanged its oxygen subsequent to secondary alteration. This isotopic exchange in melilite and anorthite likely occurred on the CV parent asteroid, possibly during fluid-assisted thermal metamorphism. © 2008 Elsevier Ltd. All rights reserved.
  • Alexander N. Krot, Hisayoshi Yurimoto, Ian D. Hutcheon, Guy Libourel, Guy Libourel, Marc Chaussidon, Laurent Tissandier, Michael I. Petaev, Glenn J. MacPherson, Julie Paque-Heather, David Wark
    Geochimica et Cosmochimica Acta 71 (17) 4342 - 4364 0016-7037 2007/09 [Refereed][Not invited]
     
    The coarse-grained, igneous, anorthite-rich (Type C) CAIs from Allende studied (100, 160, 6-1-72, 3529-40, CG5, ABC, TS26, and 93) have diverse textures and mineralogies, suggesting complex nebular and asteroidal formation histories. CAIs 100, 160, 6-1-72, and 3529-40 consist of Al,Ti-diopside (fassaite; 13-23 wt% Al2O3, 2-14 wt% TiO2), Na-bearing åkermanitic melilite (0.1-0.4 wt% Na2O; Åk30-75), spinel, and fine-grained (∼5-10 μm) anorthite groundmass. Most of the fassaite and melilite grains have "lacy" textures characterized by the presence of abundant rounded and prismatic inclusions of anorthite ∼5-10 μm in size. Lacy melilite is pseudomorphed to varying degrees by grossular, monticellite, and pure forsterite or wollastonite. CAI 6-1-72 contains a relict Type B CAI-like portion composed of polycrystalline gehlenitic melilite (Åk10-40), fassaite, spinel, perovskite, and platinum-group element nuggets; the Type B-like material is overgrown by lacy melilite and fassaite. Some melilite and fassaite grains in CAIs 100 and 160 are texturally similar to those in the Type B portion of 6-1-72. CAIs ABC and TS26 contain relict chondrule fragments composed of forsteritic olivine and low-Ca pyroxene; CAI 93 is overgrown by a coarse-grained igneous rim of pigeonite, augite, and anorthitic plagioclase. These three CAIs contain very sodium-rich åkermanitic melilite (0.4-0.6 wt% Na2O; Åk63-74) and Cr-bearing Al,Ti-diopside (up to 1.6 wt% Cr2O3, 1-23 wt% Al2O, 0.5-7 wt% TiO2). Melilite and anorthite in the Allende Type C CAI peripheries are replaced by nepheline and sodalite, which are crosscut by andradite-bearing veins; spinel is enriched in FeO. The CAI fragment CG5 is texturally and mineralogically distinct from other Allende Type Cs. It is anorthite-poor and very rich in spinel poikilitically enclosed by Na-free gehlenitic melilite (Åk20-30), fassaite, and anorthite; neither melilite nor pyroxene have lacy textures; secondary minerals are absent. The Al-rich chondrules 3655b-2 and 3510-7 contain aluminum-rich and ferromagnesian portions. The Al-rich portions consist of anorthitic plagioclase, Al-rich low-Ca pyroxene, and Cr-bearing spinel; the ferromagnesium portions consist of fosteritic olivine, low-Ca pyroxene, and opaque nodules. We conclude that Type C CAIs 100, 160, 6-1-72, and 3529-40 formed by melting of coarse-grained Type B-like CAIs which experienced either extensive replacement of melilite and spinel mainly by anorthite and diopside (traces of secondary Na-bearing minerals, e.g., nepheline or sodalite, might have formed as well), or addition of silica and sodium during the melting event. CG5 could have formed by melting of fine-grained spinel-melilite CAI with melilite and spinel partially replaced anorthite and diopside. CAIs ABC, 93, and TS-26 experienced melting in the chondrule-forming regions with addition of chondrule-like material, such as forsteritic olivine, low-Ca pyroxene, and high-Ca pyroxene. Anorthite-rich chondrules formed by melting of the Al-rich (Type C CAI-like) precursors mixed with ferromagnesian, Type I chondrule-like precursors. The Allende Type C CAIs and Al-rich chondrules experienced fluid-assisted thermal metamorphism, which resulted in pseudomorphic replacement of melilite and anorthite by grossular, monticellite, and forsterite (100, 160, 6-1-72, 3592-40) or by grossular, monticellite, and wollastonite (ABC, 93, TS-26). The pseudomorphic replacement was followed or accompanied by iron-alkali metasomatic alteration resulting in replacement of melilite and anorthite by nepheline and sodalite, enrichment of spinel in FeO, and precipitation of salite-hedenbergite pyroxenes, wollastonite, and andradite in fractures and pores in and around CAIs. © 2007.
  • Sakamoto N, Seto Y, Itoh S, Kuramoto K, Fujino K, Nagashima K, Krot AN, Yurimoto H
    Science (New York, N.Y.) 317 (5835) 231 - 233 0036-8075|1095-9203 2007/07 [Refereed][Not invited]
  • Shoichi Itoh, Shoichi Itoh, Sara S. Russell, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 42 (7-8) 1241 - 1247 10869379 2007/07 [Refereed][Not invited]
     
    Amoeboid olivine aggregates (AOAs) in the LL3.0 Semarkona chondrite have been studied by secondary ion mass spectrometry. The AOAs mainly consist of aggregates of olivine grains with interstitial Al-Ti-rich diopside and anorthite. Oxygen-isotopic compositions of all phases are consistently enriched in 16O, with δ17,18O = ∼-50‰. The initial 26Al/27Al ratios are calculated to be 5.6 ± 0.9 (2σ) × 10-5. These values are equivalent to those of AOAs and fine-grained calcium- aluminum-rich inclusions (FGls) from pristine carbonaceous chondrites. This suggests that AOAs in ordinary chondrites formed in the same 16O-rich calcium-aluminum-rich inclusion (CAI)-forming region of the solar nebula as AOAs and FGIs in carbonaceous chondrites, and subsequently moved to the accretion region of the ordinary chondrite parent body in the solar nebula. © The Meteoritical Society, 2007.
  • Alexander N. Krot, Hisayoshi Yurimoto, Ian D. Hutcheon, Marc Chaussidon, Glenn J. MacPherson, Julie Paque
    Meteoritics and Planetary Science 42 (7-8) 1197 - 1219 10869379 2007/07 [Refereed][Not invited]
     
    We describe the mineralogy, petrology, oxygen, and magnesium isotope compositions of three coarse-grained, igneous, anorthite-rich (type C) Ca-Al-rich inclusions (CAIs) (ABC, TS26, and 93) that are associated with ferromagnesian chondrule-like silicate materials from the CV carbonaceous chondrite Allende. The CAIs consist of lath-shaped anorthite (An99), Cr-bearing Al-Ti-diopside (Al and Ti contents are highly variable), spinel, and highly åkermanitic and Na-rich melilite (Åk63-74, 0.4-0.6 wt% Na2O). TS26 and 93 lack Wark-Lovering rim layers; ABC is a CAI fragment missing the outermost part. The peripheral portions of TS26 and ABC are enriched in SiO2 and depleted in TiO2 and Al2O3 compared to their cores and contain relict ferromagnesian chondrule fragments composed of forsteritic olivine (Fa6-8) and low-Ca pyroxene/pigeonite (Fs1Wo1-9). The relict grains are corroded by Al-Ti-diopside of the host CAIs and surrounded by haloes of augite Fs0.5 Wo30-42). The outer portion of CAI 93 enriched in spinel is overgrown by coarse-grained pigeonite (Fs0.5-2 Wo5-17). augite (Fs0.5 Wo38-42), and anorthitic plagioclase (An84). Relict olivine and low-Ca pyroxene/pigeonite in ABC and TS26, and the pigeonite-augite rim around 93 are 16O-poor (δ 17O ∼ -1‰ to -8‰). Spinel and Al-Ti-diopside in cores of CAIs ABC, TS26, and 93 are 16O-enriched (δ17O down to -20‰), whereas Al-Ti-diopside in the outer zones, as well as melilite and anorthite, are 16O-depleted to various degrees (δ 17O = -11‰ to 2‰). In contrast to typical Allende CAls that have the canonical initial 26Al/27Al ratio of ∼5 × 10-5, ABC, 93, and TS26 are 26Al-poor with (26 Al/27Al)0 ratios of (4.7 ± 1.4) × 10-6, (1.5 ± 1.8) × 10-6, and <1.2 × 10-6, respectively. We conclude that ABC, TS26, and 93 experienced remelting with addition of ferromagnesian chondrule silicates and incomplete oxygen isotopic exchange in an 16O-poor gaseous reservoir, probably in the chondrule-forming region. This melting episode could have reset the 26Al-26Mg systematics of the host CAIs, suggesting it occurred ∼2 Myr after formation of most CAIs. These observations and the common presence of relict CAIs inside chondrules suggest that CAIs predated formation of choudrules. © The Meteoritical Society, 2007.
  • Hisayoshi Yurimoto
    AIP Conference Proceedings 847 319 - 323 1551-7616|0094-243X 2006/12 [Refereed][Not invited]
     
    Presolar circumstellar grains have been surveyed in 18 primitive meteorites. More than hundreds presolar grains have been identified. Presolar silicates are the most abundant species among presolar grains. The typical size is ∼300 nm and the abundance is ∼50 ppm in the most primitive chondrites. Main source of silicate presolar grains is from AGB and red giant stars. The average O-isotopic composition of presolar silicates is enriched in 17O relative to the solar composition. The counterpart to form solar isotope ratios having 17O-depleted compositions are missing in the chondrites. The missing matter would be supernovae ejecta but it is difficult to identify because the grain size is expected to be ∼10 nm. © 2006 American Institute of Physics.
  • Motoo Ito, Motoo Ito, Hiroshi Nagasawa, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 41 (12) 1871 - 1881 10869379 2006/12 [Refereed][Not invited]
     
    The measurements of magnesium and potassium isotopic compositions of refractory minerals in Allende calcium-aluminum-rich inclusions (CAIs), 7R-19-1, HN3-1, and EGG3 were taken by secondary ion mass spectrometry (SIMS). The 7R-19-1 contains 16O-rich and 16O-poor melilite grains and define a single isochron corresponding to an initial 26Al/27Al ratio of (6.6 ± 1.3) × 10-5. The Al-Mg isochron, O isotope measurements and petrography of melilite in 7R-19-1 indicate that 16O-poor melilite crystallized within 0.4 Myr after crystallization of 16O-rich melilite, suggesting that oxygen isotopic composition of the CAI-forming region changed from 16O-rich to 16O-poor within this time interval. The 16O-poor melilite is highly depleted in K compared to the adjacent 16O-rich melilite, indicating evaporation during remelting of 7R-19-1. We determined the isochron for 41Ca-41K isotopic systematics in EGG3 pyroxene with (4.1 ± 2.0) × 10-9 (2σ) as an initial ratio of 41Ca/40Ca, which is at least two times smaller than the previous result (Sahijipal et al. 2000). The ratio of 41Ca/40Ca in the EGG3 pyroxene grain agrees within error with the value obtained by Hutcheon et al. (1984). No evidence for the presence of 41K excess (decay product of a short-lived radionuclide 41Ca) was found in 7R-19-1 and HN3-1. We infer that the CAI had at least an order of magnitude lower than canonical 41Ca/40Ca ratio at the time of the CAI formation. © The Meteoritical Society, 2006.
  • Naoya Sakamoto, Hisayoshi Yurimoto
    Surface and Interface Analysis 38 (12-13) 1760 - 1762 1096-9918|0142-2421 2006/12 [Refereed][Not invited]
     
    A direct ion imaging system with single ion detection and high-precision imaging modes has been developed. This system is composed of a movable microchannel plate unit and a stacked CMOS-type active pixel sensor (SCAPS). Capabilities of single ion detection were evaluated by ion irradiations using secondary ion mass spectrometry. The experiment shows that this system accurately detected single incident ions. Copyright © 2006 John Wiley & Sons, Ltd.
  • K. D. Litasov, Yu D. Litasov, A. V. Ivanov, S. V. Rasskazov, H. Yurimoto, E. I. Demonterova, V. V. Sharygin, V. G. Mal'kovets
    Geologiya i Geofizika 47 132 - 152 00167886 2006/12 [Refereed][Not invited]
     
    Study was given to Cr-diopside group mantle xenoliths from Late Cenozoic basaltoids of the Udokan volcanic field located at the boundary of the Aldan Shield and Baikal-Vitim terrane. Slightly depleted lherzolites are predominant xenoliths in the central part of the field (Pliocene basanites of Lake Kuas), whereas depleted harzburgites prevail in its northern part. The composition of the Udokan peridotites suggests that they are components of the Phanerozoic oceanic mantle subducted beneath the Siberian craton rather than the Archean mantle of the Aldan Shield. Xenoliths of Lake Kuas are divided into two series: harzburgite-lherzolite and lherzolite-websterite. The latter series probably represents ancient mantle, whereas the former might have been resulted from the later interaction of peridotites with hypothetic silicate melt, which was probably accompanied by Na-amphibole metasomatism. The Kuas spinel harzburgites and dunites are characterized by higher equilibrium temperatures (1000-1050°C) and higher oxidation state (average Δlogf O2 (QFM) = -1.0) than the other rocks. Lherzolites have T = 950-1050°C and average ΔlogfO2 (QFM) = -1.9, and websterites have T = 900-1000°C and average ΔlogfO2 (QFM) = -3.1. Hence, having the same geothermal gradient, the harzburgite-lherzolite association formed at a greater depth than the lherzolite-websterite one. Most of the northern Udokan peridotites are highly oxidized; peridotites of the Ingamakit and Munduzhyak Volcanoes have ΔlogfO2 (QFM) of -1 to +2. Two-pyroxene temperatures calculated for the Munduzhyak peridotites are higher (1050-1200°C) than those for the other mantle xenoliths, whereas the Ca-orthopyroxene temperatures are low for all xenoliths (800-900°C). Depleted harzburgite xenoliths of the Udokan field contain clinopyroxenes enriched in LREE and depleted in Nb, Zr, and Ti. These element patterns might be explained by the reaction of the peridotites with percolating silicate melt or fluid. The high contents of LREE and MREE reflect the final stage of the peridotite-melt interaction, when depleted peridotites reached an equilibrium with the melt (fluid).
  • Alexander N. Krot, Hisayoshi Yurimoto, Kevin D. McKeegan, Laurie Leshin, Marc Chaussidon, Guy Libourel, Guy Libourel, Miwa Yoshitake, Gary R. Huss, Yunbin Guan, Brigitte Zanda
    Chemie der Erde - Geochemistry 66 (4) 249 - 276 0009-2819 2006/11 [Refereed][Not invited]
     
    We review the oxygen isotopic compositions of minerals in chondrules and compound objects composed of a chondrule and a refractory inclusion, and bulk oxygen isotopic compositions of chondrules in unequilibrated ordinary, carbonaceous, enstatite, and Kakangari-like chondrites, focusing on data acquired using secondary ion mass-spectrometry and laser fluorination coupled with mass-spectrometry over the last decade. Most ferromagnesian chondrules from primitive (unmetamorphosed) chondrites are isotopically uniform (within 3-4‰ in Δ17O) and depleted in 16O (Δ17O>-7‰) relative to amoeboid olivine aggregates (AOAs) and most calcium-aluminum-rich inclusions (CAIs) (Δ17O<-20‰), suggesting that these classes of objects formed in isotopically distinct gaseous reservoirs, 16O-poor and 16O-rich, respectively. Chondrules uniformly enriched in 16O (Δ17O<-15‰) are exceptionally rare and have been reported only in CH chondrites. Oxygen isotopic heterogeneity in chondrules is mainly due to the presence of relict grains. These appear to consist of chondrules of earlier generations and rare refractory inclusions; with rare exceptions, the relict grains are 16O-enriched relative to chondrule phenocrysts and mesostasis. Within a chondrite group, the magnesium-rich (Type I) chondrules tend to be 16O-enriched relative to the ferrous (Type II) chondrules. Aluminum-rich chondrules in ordinary, enstatite, CR, and CV chondrites are generally 16O-enriched relative to ferromagnesian chondrules. No systematic differences in oxygen isotopic compositions have been found among these chondrule types in CB chondrites. Aluminum-rich chondrules in carbonaceous chondrites often contain relict refractory inclusions. Aluminum-rich chondrules with relict CAIs have heterogeneous oxygen isotopic compositions (Δ17O ranges from -20‰ to 0‰). Aluminum-rich chondrules without relict CAIs are isotopically uniform and have oxygen isotopic compositions similar to, or approaching, those of ferromagnesian chondrules. Phenocrysts and mesostases of the CAI-bearing chondrules show no clear evidence for 16O-enrichment compared to the CAI-free chondrules. Spinel, hibonite, and forsterite of the relict refractory inclusions largely retained their original oxygen isotopic compositions. In contrast, plagioclase and melilite of the relict CAIs experienced melting and 16O-depletion to various degrees, probably due to isotopic exchange with an 16O-poor nebular gas. Several igneous CAIs experienced isotopic exchange with an 16O-poor nebular gas during late-stage remelting in the chondrule-forming region. On a three-isotope diagram, bulk oxygen isotopic compositions of most chondrules in ordinary, enstatite, and carbonaceous chondrites plot above, along, and below the terrestrial fractionation line, respectively. Bulk oxygen isotopic compositions of chondrules in altered and/or metamorphosed chondrites show evidence for mass-dependent fractionation, reflecting either interaction with a gaseous/fluid reservoir on parent asteroids or open-system thermal metamorphism. Bulk oxygen isotopic compositions of chondrules and oxygen isotopic compositions of individual minerals in chondrules and refractory inclusions from primitive chondrites plot along a common line of slope of ∼1, suggesting that only two major reservoirs (gas and solids) are needed to explain the observed variations. However, there is no requirement that each had a permanently fixed isotopic composition. The absolute (207Pb-206Pb) and relative (27Al-26Mg) chronologies of CAIs and chondrules and the differences in oxygen isotopic compositions of most chondrules (16O-poor) and most refractory inclusions (16O-rich) can be interpreted in terms of isotopic self-shielding during UV photolysis of CO in the initially 16O-rich (Δ17O∼-25‰) parent molecular cloud or protoplanetary disk. According to these models, the UV photolysis preferentially dissociates C17O and C18O in the parent molecular cloud and in the peripheral zones of the protoplanetary disk. If this process occurs in the stability field of water ice, the released atomic 17O and 18O are incorporated into water ice, while the residual CO gas becomes enriched in 16O. During the earliest stages of evolution of the protoplanetary disk, the inner solar nebula had a solar H2O/CO ratio and was 16O-rich. During this time, AOAs and the 16O-rich CAIs and chondrules formed. Subsequently, the inner solar nebula became H2O- and 16O-depleted, because ice-rich dust particles, which were depleted in 16O, agglomerated outside the snowline (∼5 AU), drifted rapidly towards the Sun and evaporated. During this time, which may have lasted for ∼3 Myr, most chondrules and the 16O-depleted igneous CAIs formed. We infer that most chondrules formed from isotopically heterogeneous, but 16O-depleted precursors, and experienced isotopic exchange with an 16O-poor nebular gas during melting. Although the relative roles of the chondrule precursor materials and gas-melt isotopic exchange in establishing oxygen isotopic compositions of chondrules have not been quantified yet, mineralogical, chemical, and isotopic evidence indicate that Type I chondrules may have formed in chemical and isotopic equilibrium with nebular gas of variable isotopic composition. Whether these variations were spatial or temporal are not known yet. © 2006 Elsevier GmbH. All rights reserved.
  • Krot Alexander N., Yurimoto Hisayoshi, Ciesla Fred J., Lyons James R.
    GEOCHIMICA ET COSMOCHIMICA ACTA 70 (18) A337  0016-7037 2006/08 [Refereed][Not invited]
  • Anders Meibom, Anders Meibom, Hiyayoshi Yurimoto, Hiyayoshi Yurimoto, Jean Pierre Cuif, Isabelle Domart-Coulon, Fanny Houlbreque, Fanny Houlbreque, Brent Constantz, Yannicke Dauphin, E. Tambutté, Sylvie Tambutté, Denis Allemand, Joseph Wooden, Robert Dunbar
    Geophysical Research Letters 33 00948276 2006/06 [Refereed][Not invited]
     
    Biological control over coral skeletal composition is poorly understood but critically important to paleoenvironmental reconstructions. We present microanalytical measurements of trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate coral Colpophyllia sp. Our data show that centers of calcification (COC) have higher trace element concentrations and distinctly lighter isotopic compositions than the fibrous components of the skeleton. These observations necessitate that COC and the fibrous skeleton are precipitated by different mechanisms, which are controlled by specialized domains of the calicoblastic cell-layer. Biological processes control the composition of the skeleton even at the ultra-structure level. Copyright 2006 by the American Geophysical Union.
  • Ikuo Katayama, Ikuo Katayama, Satoru Nakashima, Satoru Nakashima, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Lithos 86 245 - 259 00244937 2006/02 [Refereed][Not invited]
     
    Infrared spectroscopy and ion micro-probe measurements showed that the major constituent minerals of eclogites from the Kokchetav massif, which have been subducted to ∼180 km depths, contain significant amounts of water up to 870 ppm H2O (by weight) in omphacite, 130 ppm H2O in garnet and 740 ppm H2O in rutile. Omphacite shows three hydroxyl absorption bands at 3440-3460, 3500-3530 and 3600-3625 cm-1, garnet has a single band at 3580-3630 cm-1 and rutile has a single sharp band at 3280 cm-1. The hydroxyl absorbance at these wavenumbers changes with the crystal orientation in polarized infrared radiation, indicating that the water is structurally incorporated in these minerals. The water contents in omphacite and garnet increase systematically with the metamorphic pressure of the host eclogites. The partitioning coefficient of the water content between coexisting garnet and omphacite is similar in different eclogites, DGrt/Omp∼0.1-0.2, but decreases slightly at high pressure. Based on the mineral proportions of the eclogites, we estimate bulk-rock water content in the eclogites ranging from 3070 to 300 ppm H2O (by weight). Although hydrous minerals are absent in the diamond-grade eclogite (∼60 kbar and ∼1000 °C), trace amounts of water are incorporated in the nominally anhydrous minerals such as omphacite and garnet. The presence of significant water in these minerals implies that the subducting oceanic crust can transport considerable amounts of water into the deep upper mantle beyond the stability of hydrous minerals. Such water may be stored in the deep upper mantle and have an important influence on dynamics in the Earth's interior. © 2005 Elsevier B.V. All rights reserved.
  • Michihiko Nakamura, Hisayoshi Yurimoto, Hisayoshi Yurimoto, E. Bruce Watson
    Geology 33 829 - 832 00917613 2005/10 [Refereed][Not invited]
     
    Isotope exchange between fluid and rocks has been traditionally considered to be rate limited by two elementary processes: lattice diffusion in the matrix minerals and dissolution into the fluid followed by precipitation from it. In this study we show the results of high-pressure experiments on 18O-water infiltration into quartzite that point to a third, highly efficient process: grain growth accompanied by migration of the grain boundaries (GBs) that are isotopically enriched by GB diffusion and surface exchange. We predict on the basis of a mass-transfer mechanism discrimination diagram that this GB sweeping is the primary control on isotopic equilibration under hydrothermal conditions in various fine-grained rocks with low fluid fraction. Grain growth should be considered when interpreting and simulating isotope and chemical composition of rocks and fluids. © 2005 Geological Society of America.
  • H. Yurimoto, K. Nagashima
    Microscopy and Microanalysis 11 196 - 197 14319276 2005/08 [Refereed][Not invited]
  • Miwa Yoshitake, Miwa Yoshitake, Yoshiyuki Koide, Yoshiyuki Koide, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 69 2663 - 2674 00167037 2005/05 [Refereed][Not invited]
     
    Oxygen-isotopic compositions in conjunction with petrologic investigation have been determined for a coarse-grained type B2 Ca, Al-rich inclusion (CAI) from the reduced CV3 Vigarano using secondary ion mass spectrometry. The oxygen-isotopic compositions of minerals are distributed along the carbonaceous chondrite anhydrous mineral line indicating mixing between 16O-rich and 16O-poor nebular components. The O-isotopic heterogeneities among and within minerals in the CAI interior indicate that CAI formation started in an 16O-rich nebula and subsequently continued in an 16O-poor nebula. 16O-rich signatures of melilite and fassaite in the Wark-Lovering rim and of olivine of the accretionary rim indicate that the nebular environment during formation of the CAI returned to an 16O-rich composition after processing in an 16O-poor nebula. These O-isotopic variations in the CAI support multiple heating events in the solar nebula and indicate that the nebular environments fluctuated from 16O-rich to 16O-poor and back to 16O-rich compositions during the formation of a single CAI. Copyright © 2005 Elsevier Ltd.
  • Alexander N. Krot, Timothy J. Fagan, Timothy J. Fagan, Kazuhide Nagashima, Michael I. Petaev, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 69 1873 - 1881 00167037 2005/04 [Refereed][Not invited]
     
    Amoeboid olivine aggregates (AOAs) in primitive carbonaceous chondrites consist of forsterite (Falt;2), Fe,Ni-metal, spinel, Al-diopside, anorthite, and rare gehlenitic melilite (Åk<15). ∼10% of AOAs contain low-Ca pyroxene (Fs1-3Wo1-5) that is in corrosion relationship with forsterite and is found in three major textural occurrences: (i) thin (<5 μm) discontinuous layers around forsterite grains or along forsterite grain boundaries in AOA peripheries; (ii) 5-10-μm-thick haloes and subhedral grains around Fe,Ni-metal nodules in AOA peripheries, and (iii) shells of variable thickness (up to 70 μm), commonly with abundant tiny (3-5 μm) inclusions of Fe,Ni-metal grains, around AOAs. AOAs with the low-Ca pyroxene shells are compact and contain euhedral grains of Al-diopside surrounded by anorthite, suggesting small (10%-20%) degree of melting. AOAs with other textural occurrences of low-Ca pyroxene are rather porous. Forsterite grains in AOAs with low-Ca pyroxene have generally 16O-rich isotopic compositions (Δ17O lt; -20‰). Low-Ca pyroxenes of the textural occurrences (i) and (ii) are 16O-enriched (Δ17O < -20‰), whereas those of (iii) are 16O-depleted (Δ17O = -6‰ to -4‰). One of the extensively melted (>50%) objects is texturally and mineralogically intermediate between AOAs and Al-rich chondrules. It consists of euhedral forsterite grains, pigeonite, augite, anorthitic mesostasis, abundant anhedral spinel grains, and minor Fe,Ni-metal; it is surrounded by a coarse-grained igneous rim largely composed of low-Ca pyroxene with abundant Fe,Ni-metal-sulfide nodules. The mineralogical observations suggest that only spinel grains in this igneous object were not melted. The spinel is 16O-rich (Δ17O ∼ -22‰), whereas the neighboring plagioclase mesostasis is 16O-depleted (Δ17O ∼ -11‰). We conclude that AOAs are aggregates of solar nebular condensates (forsterite, Fe,Ni-metal, and CAIs composed of Al-diopside, anorthite, spinel, and ±melilite) formed in an 16O-rich gaseous reservoir, probably CAI-forming region(s). Solid or incipiently melted forsterite in some AOAs reacted with gaseous SiO in the same nebular region to form low-Ca pyroxene. Some other AOAs appear to have accreted 16O-poor pyroxene-normative dust and experienced varying degrees of melting, most likely in chondrule-forming region(s). The most extensively melted AOAs experienced oxygen isotope exchange with 16O-poor nebular gas and may have been transformed into chondrules. The original 16O-rich signature of the precursor materials of such chondrules is preserved only in incompletely melted grains. Copyright © 2005 Elsevier Ltd.
  • Alexander N. Krot, Ian D. Hutcheon, Hisayoshi Yurimoto, Jeffrey N. Cuzzi, Kevin D. McKeeoan, Edward R D Scott, Guy Libourel, Guy Libourel, Marc Chaussidon, Jerome Aléon, Michael I. Petaev
    Astrophysical Journal 622 1333 - 1342 0004637X 2005/04 [Refereed][Not invited]
     
    Changes in the chemical and isotopic composition of the solar nebula with time are reflected in the properties of different constituents that are preserved in chondritic meteorites. CR-group carbonaceous chondrites are among the most primitive of all chondrite types and must have preserved solar nebula records largely unchanged. We have analyzed the oxygen and magnesium isotopes in a range of the CR constituents of different formation temperatures and ages, including refractory inclusions and chondrules of various types. The results provide new constraints on the time variation of the oxygen isotopic composition of the inner (<5 AU) solar nebula - the region where refractory inclusions and chondrules most likely formed. A chronology based on the decay of short-lived 26A1 (t1/2 ∼ 0.73 Myr) indicates that the inner solar nebula gas was 16O-rich when refractory inclusions formed, but less than 0.8 Myr later, gas in the inner solar nebula became 16O-poor, and this state persisted at least until CR chondrules formed ∼1-2 Myr later. We suggest that the inner solar nebula became 16O-poor because meter-sized icy bodies, which were enriched in 17O and 18O as a result of isotopic self-shielding during the ultraviolet photo-dissociation of CO in the protosolar molecular cloud or protoplanetary disk, agglomerated outside the snow line, drifted rapidly toward the Sun, and evaporated at the snow line. This led to significant enrichment in 16O-depleted water, which then spread through the inner solar system. Astronomical studies of the spatial and temporal variations of water abundance in protoplanetary disks may clarify these processes. © 2005. The American Astronomical Society. All rights reserved.
  • Krot AN, Yurimoto H, Hutcheon ID, MacPherson GJ
    Nature 434 (7036) 998 - 1001 1476-4687|0028-0836 2005/04 [Refereed][Not invited]
  • Toshiaki Tsunogae, Hisayoshi Yurimoto
    Science Reports of the University of Tsukuba, Institute of Geoscience, Section B: Geological Sciences 26 23 - 38 03886182 2005/03 [Refereed][Not invited]
     
    Single zircon 207Pb/206Pb and U-Pb ages of granulite-facies quartzo-feldspathic gneisses from the Northern Marginal Zone (NMZ) of the Limpopo Belt, southern Africa, were examined by a secondary ion mass spectrometry (SIMS). The NMZ is composed mainly of charnockite and associated leucocratic rocks. Some of them contain a mineral assemblage of euhedral orthopyroxene and megaperthite, probably formed by a high-grade partial melting around the peak P-T condition of the NMZ (T∼800°C). Our new zircon ages for the rocks indicate emplacement of tonalitic to granodioritic plutons at >2.79 Ga and subsequent granulite-facies metamorphism at 2.62 to 2.71 Ga. The results suggest that the peak metamorphic age of the NMZ is almost consistent with that of the Southern Marginal Zone of the belt (2.70 to 2.65 Ga; Barton and van Reenen, 1992). We therefore confirmed that the two zones have been subjected to the peak metamorphism during late Archean probably by a collision of Zimbabwe and Kaapvaal Cratons.
  • Takanori Koshikawa, Takanori Koshikawa, Yoshikazu Homma, Hisayoshi Yurimoto
    Surface and Interface Analysis 37 95  01422421 2005/02 [Refereed][Not invited]
  • Takuya Kunihiro, Takuya Kunihiro, Kazuhide Nagashima, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 69 763 - 773 00167037 2005/02 [Refereed][Not invited]
     
    Two-dimensional 18O/16O isotopic analysis of the Vigarano matrix was conducted by secondary ion-imaging using a novel two-dimensional ion-imager. Quantitative oxygen-isotope images (isotopographs) of the Vigarano matrix show that 16O-rich micrograins are scattered within 16O-poor matrix. This heterogeneous O-isotopic distribution indicates that matrix is composed of different O-isotopic components that formed in different locations and/or at different times. However, the O-isotopic composition of groundmass in the matrix is the same as the bulk isotopic composition of the matrix within ±5‰ uncertainty. The spatial resolution and isotopic precision of our technique should allow submicron-size objects (>0.2 μm) with extreme O-isotopic anomalous characteristics (δ18OSMOW ∼250‰) to be detectable in isotopographs. Because the mean grain size of the matrix is ∼0.2 μm, the inability to detect such O-isotopic anomalous objects indicates that isotopically anomalous micrograins (e.g., presolar grains) are extremely rare in the Vigarano matrix and that most objects in the matrix were formed in the solar nebula or in the parent body. Copyright © 2005 Elsevier Ltd.
  • Yohei Shimizu, Shoji Arai, Tomoaki Morishita, Hisayoshi Yurimoto, Fernando Gervilla
    Transactions of the Royal Society of Edinburgh, Earth Sciences 95 265 - 276 02635933 2004/12 [Refereed][Not invited]
     
    Felsic and related veins within mantle-derived peridotite xenoliths from Tallante, Spain, were examined in order to understand the mantle-wedge processes related to the behaviour of Si-rich melt. The thickest part of the vein has a quartz diorite lithology, and is composed mainly of quartz and plagioclase, with pyroxenes, hydrous mineral, apatite, zircon and rutile present as minor phases. The thinner parts are free of quartz and predominantly composed of plagioclase. Orthopyroxene always intervenes between the internal part (plagioclase ± quartz) and host peridotite, indicating that it is a product of interaction between silica-oversaturated melt and olivine. This indicates that a sufficiently high melt/wall rock ratio enabled the melt to retain its silica-oversaturated character. The quartz diorite part has adakite-lik e geochemical signatures, except for negative Ba, Rb Eu and Sr anomalies, and positive Th and U anomalies. These negative anomalies indicate that fractionation of plagioclase and hydrous minerals was achieved between the upper most mantle and the slab melting zone. The shape of the rare-earth element (REE) pattern of clinopyroxene in quartz diorite is strikingly similar to that of clinopyroxene phenocrysts from Aleutian adakites. However, the former has one order higher REE contents than the latter, except for Eu which shows a prominent negative spike. This feature was caused by the precipitation of large amounts of plagioclase and small amounts of clinopyroxene from a fractionated adakitic melt before and during solidification. This adakitic melt was produced by partial melting of a detached and sinking slab beneath the Betic area in the Tertiary.
  • Alexander N. Krot, Michail I. Petaev, Sara S. Russell, Shoichi Itoh, Shoichi Itoh, Timothy J. Fagan, Timothy J. Fagan, Hisayoshi Yurimoto, Lysa Chizmadia, Michael K. Weisberg, Michael K. Weisberg, Matsumi Komatsu, Alexander A. Ulyanov, Klaus Keil
    Chemie der Erde - Geochemistry 64 185 - 239 00092819 2004/09 [Refereed][Not invited]
     
    Amoeboid olivine aggregates (AOAs) are the most common type of refractory inclusions in CM, CR, CH, CV, CO, and ungrouped carbonaceous chondrites Acfer 094 and Adelaide; only one AOA was found in the CBb chondrite Hammadah al Hamra 237 and none were observed in the CBa chondrites Bencubbin, Gujba, and Weatherford. In primitive (unaltered and unmetamorphosed) carbonaceous chondrites, AOAs consist of forsterite (Fa<2), Fe, Ni-metal (5-12 wt% Ni), and Ca, Al-rich inclusions (CAIs) composed of Al-diopside, spinel, anorthite, and very rare melilite. Melilite is typically replaced by a fine-grained mixture of spinel, Al-diopside, and ±anorthite; spinel is replaced by anorthite. About 10% of AOAs contain low-Ca pyroxene replacing forsterite. Forsterite and spinel are always 16O-rich (δ17,18O∼-40‰ to -50‰), whereas melilite, anorthite, and diopside could be either similarly 16O-rich or 16O-depleted to varying degrees; the latter is common in AOAs from altered and metamorphosed carbonaceous chondrites such as some CVs and COs. Low-Ca pyroxene is either 16O-rich (δ17,18O∼-40‰) or 16O-poor (δ17,18O∼0‰). Most AOAs in CV chondrites have unfractionated (∼2-10×CI) rare-earth element patterns. AOAs have similar textures, mineralogy and oxygen isotopic compositions to those of forsterite-rich accretionary rims surrounding different types of CAIs (compact and fluffy Type A, Type B, and fine-grained, spinel-rich) in CV and CR chondrites. AOAs in primitive carbonaceous chondrites show no evidence for alteration and thermal metamorphism. Secondary minerals in AOAs from CR, CM, and CO, and CV chondrites are similar to those in chondrules, CAIs, and matrices of their host meteorites and include phyllosilicates, magnetite, carbonates, nepheline, sodalite, grossular, wollastonite, hedenbergite, andradite, and ferrous olivine. Our observations and a thermodynamic analysis suggest that AOAs and forsterite-rich accretionary rims formed in 16O-rich gaseous reservoirs, probably in the CAI-forming region(s), as aggregates of solar nebular condensates originally composed of forsterite, Fe, Ni-metal, and CAIs. Some of the CAIs were melted prior to aggregation into AOAs and experienced formation of Wark-Lovering rims. Before and possibly after the aggregation, melilite and spinel in CAIs reacted with SiO and Mg of the solar nebula gas enriched in 16O to form Al-diopside and anorthite. Forsterite in some AOAs reacted with 16O-enriched SiO gas to form low-Ca pyroxene. Some other AOAs were either reheated in 16O-poor gaseous reservoirs or coated by 16O-depleted pyroxene-rich dust and melted to varying degrees, possibly during chondrule formation. The most extensively melted AOAs experienced oxygen isotope exchange with 16O-poor nebular gas and may have been transformed into magnesian (Type I) chondrules. Secondary mineralization and at least some of the oxygen isotope exchange in AOAs from altered and metamorphosed chondrites must have resulted from alteration in the presence of aqueous solutions after aggregation and lithification of the chondrite parent asteroids. © 2004 Elsevier GmbH. All rights reserved.
  • John T. Wasson, Alan E. Rubin, Hisayoshi Yurimoto
    Meteoritics and Planetary Science 39 1591 - 1598 10869379 2004/09 [Refereed][Not invited]
     
    Several recent studies have shown that materials such as magnetite that formed in asteroids tend to have higher Δ 17O (=δ 17O - 0.52 x δ 18O) values than those recorded in unaltered chondrules. Other recent studies have shown that, in sets of chondrules from carbonaceous chondrites, Δ 17O tends to increase as the FeO contents of the silicates increase. We report a comparison of the O isotopic composition of olivine phenocrysts in low-FeO (≤Fa1) type I and high-FeO (≥Fa15) type II porphyritic chondrules in the highly primitive CO3.0 chondrite Yamato-81020. In agreement with a similar study of chondrules in CO3.0 ALH A77307 by Jones et al. (2000), Δ 17O tends to increase with increasing FeO. We find that Δ 17O values are resolved (but only marginally) between the two sets of olivine phenocrysts. In two of the high-FeO chondrules, the difference between Δ 17O of the late-formed, high-FeO phenocryst olivine and those in the low-FeO cores of relict grains is well-resolved (although one of the relicts is interpreted to be a partly melted amoeboid olivine inclusion by Yurimoto and Wasson [2002]). It appears that, during much of the chondrule-forming period, there was a small upward drift in the Δ 17O of nebular solids and that relict cores preserve the record of a different (and earlier) nebular environment. © Meteoritical Society, 2004.
  • Yurimoto H, Kuramoto K
    Science (New York, N.Y.) 305 (5691) 1763 - 1766 0036-8075|1095-9203 2004/09 [Refereed][Not invited]
  • Hisayoshi Yurimoto, Tetsu Kogiso, Tetsu Kogiso, Kanshi Abe, Hans G. Barsczus, Atsushi Utsunomiya, Shigenori Maruyama
    Physics of the Earth and Planetary Interiors 146 231 - 242 00319201 2004/08 [Refereed][Not invited]
     
    Pb isotopic compositions of melt inclusions in olivine phenocrysts of lava samples from Mangaia and Rarotonga, Cook-Austral islands, have been determined by secondary ion mass spectrometry. The Pb isotopic compositions of melt inclusions from Rarotonga are consistent with those of bulk rock. On the other hand, Pb isotopic compositions of sulfide-free melt inclusions from Mangaia Island are widely distributed along the join between HIMU (i.e. highly radiogenic Pb) and less radiogenic components. The variation is much wider than that in bulk-rock samples that are invariably end-member HIMU values. In contrast, Pb isotopic compositions of sulfide and carbonate inclusions are restricted to HIMU end-member values. The variations in Pb isotopic ratios can be explained by mixing between the HIMU component and another component with less radiogenic Pb, and suggests that the HIMU component is enriched in sulfide and carbonate phases as well as Pb compared with the less radiogenic component. It seems paradoxical that a sulfide-rich component is associated with highly radiogenic Pb, because sulfides generally have extremely low U/Pb and Th/Pb ratios, which result in quite unradiogenic Pb. Subducted oceanic crust is not a likely source for such a sulfide-rich component because sulfides in subducted crust may not survive dehydration processes in subduction zones, although it can produce highly radiogenic Pb. The association of highly radiogenic Pb and sulfides implies that sulfides and radiogenic Pb in the HIMU source originate from distinct reservoirs. A possible origin of the sulfides is the Earth's core, because the core is the largest sulfur budget in the Earth. The highly radiogenic Pb may originate from subducted oceanic crust which resides at the core-mantle boundary. Alternative source for radiogenic Pb is Ca-perovskite in the lower mantle, which is the main host of incompatible elements in the lower mantle and has high U/Pb and Th/Pb ratios. The core-derived sulfides would exchange Pb isotopes with subducted oceanic crust or Ca-perovskite during upwelling in the lower mantle, resulting in production of a sulfur-rich reservoir with highly radiogenic Pb. © 2004 Elsevier B.V. All rights reserved.
  • A. N. Krot, H. Yurimoto, M. I. Petaev, I. D. Hutcheon, D. Wark
    Meteoritics and Planetary Science 39 10869379 2004/08 [Refereed][Not invited]
  • T. J. Fagan, A. N. Krot, K. Keil, H. Yurimoto
    Meteoritics and Planetary Science 39 1257 - 1272 10869379 2004/08 [Refereed][Not invited]
     
    In situ SIMS oxygen isotope data were collected from a coarse-grained type B1 Ca-Al-rich inclusion (CAI) and an adjacent fine-grained CAI in the reduced CV3 Efremovka to evaluate the timing of isotopic alteration of these two objects. The coarse-grained CAI (CGI-10) is a sub-spherical object composed of elongate, euhedral, normally-zoned melilite crystals ranging up to several hundreds of μm in length, coarse-grained anorthite and Al, Ti-diopside (fassaite), all with fine-grained (∼10 μm across) inclusions of spinel. Similar to many previously examined coarse-grained CAIs from CV chondrites, spinel and fassaite are 16O-rich and melilite is 16O-poor, but in contrast to many previous results, anorthite is 16O-rich. Isotopic composition does not vary with textural setting in the CAI: analyses of melilite from the core and mantle and analyses from a variety of major element compositions yield consistent 16O-poor compositions. CGI-10 originated in an 16O-rich environment, and subsequent alteration resulted in complete isotopic exchange in melilite. The fine-grained CAI (FGI-12) also preserves evidence of a 1st-generation origin in an 16O-rich setting but underwent less severe isotopic alteration. FGI-12 is composed of spinel ± melilite nodules linked by a mass of Aldiopside and minor forsterite along the CAI rim. All minerals are very fine-grained (<5 μm) with no apparent igneous textures or zoning. Spinel, Al-diopside, and forsterite are 16O-rich, while melilite is variably depleted in 16O (δ17, 18O from ∼-40% to -5%). The contrast in isojtopic distributions in CGI-10 and FGI-12 is opposite to the pattern that would result from simultaneous alteration: the object with finer-grained melilite and a greater surface area/volume has undergone less isotopic exchange than the coarser-grained object. Thus, the two CAIs were altered in different settings. As the CAIs are adjacent to each other in the meteorite, isotopic exchange in CGI-10 must have preceded incorporation of this CAI in the Efremovka parent body. This supports a nebular setting for isotopic alteration of the commonly observed 16O-poor melilite in coarse-grained CAIs from CV chondrites. © Meteoritical Society, 2004.
  • A. N. Krot, H. Yurimoto, I. D. Hutcheon, E. R D Scott
    Meteoritics and Planetary Science 39 10869379 2004/08 [Refereed][Not invited]
  • Akira Shimojuku, Tomoaki Kubo, Eiji Ohtani, Hisayoshi Yurimoto
    Geophysical Research Letters 31 00948276 2004/07 [Refereed][Not invited]
     
    Si self-diffusion rates in Mg2SiO4 polycrystalline wadsleyite were measured at 18 GPa and 1430-1630°C using an isotopic tracer (29Si) and secondary ion mass spectrometry. The volume diffusion coefficient (Dv) and grain-boundary diffusion coefficient (Dgb) were determined to be Dv = 3.44 × 10-11 [m2/s] exp (-299 [kJ/mol]/RT) and δDgb = 1.14 × 10-17 [m3/s] exp (-248 [kJ/mol]/RT), respectively. Si diffusion rates in wadsleyite are about 5 orders of magnitude slower than Mg-Fe interdiffusion rates at 1400°C. Assuming that Si is the slowest diffusing species in wadsleyite, the geophysical model of the viscosity in the mantle transition zone can be explained by diffusion creep in wadsleyite for a grain size of about 0.5-5 mm. Some portions in cold subducting slabs, where the grain size reduces to less than 1 μm after the olivine-spinel transformation, become weaker than the surrounding mantle. Copyright 2004 by the American Geophysical Union.
  • Motoo Ito, Hiroshi Nagasawa, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 68 2905 - 2923 00167037 2004/07 [Refereed][Not invited]
     
    The oxygen isotopic micro-distributions within and among minerals in a coarse-grained Ca, Al-rich inclusion (CAI), 7R-19-1 from the Allende meteorite, were measured by in situ using secondary ion mass spectrometry (SIMS). All values of O isotopic ratios in 7R-19-1 minerals fall along the carbonaceous chondrite anhydrous mineral mixing (CCAM) line on a δ17OSMOW vs. δ18OSMOW plot. Major refractory minerals (spinel, fassaite and melilite) in 7R-19-1 showed large negative anomalies of Δ17O in the order, spinel (-21‰) > 16O-rich melilite (∼-18‰) > fassaite (-15 to +1‰) > 16O-poor melilite (-8 to +2‰). However, the lower limit values of Δ17O are similar at about -21‰, a value commonly observed in CAIs. The similarity in the extreme values of the isotope anomaly anomalies suggests that crystallization of all CAIs started from an 16O enrichment of 21‰ (Δ17O) relative to terrestrial values. The order of the O isotopic anomalies observed for 7R-19-1, except for 16O-poor melilite, is parallel to the crystallization sequence determined by experiment from CAI liquid (Stolper, 1982), indicating that the O isotopic exchange in 7R-19-1 occurred between CAI melt and surrounding gas while 7R-19-1 was crystallizing from the 16O enriched CAI liquid (∼-21‰ in Δ17O) in the 16O-poor solar nebula. However, the a single crystallization sequence during the cooling stage cannot explain the existence of 16O-poor melilite. The presence of 16O-poor melilite suggests that multiple heating events occurred during CAI formation. The sharp contact between 16O-rich and 16O-poor melilite crystals and within 16O-rich melilite indicates that these multiple heatings occurred quickly. Based on the O isotopic and chemical compositions, fassaite crystals were aggregates of relic crystals formed from CAI melt whichthat have had various O isotopic compositions from the remelting processes. The results of intra-mineral distributions of O isotopes also support multiple heating events during CAI formation. © 2004 Elsevier Ltd.
  • T. J. Fagan, A. N. Krot, K. Keil, H. Yurimoto
    Geochimica et Cosmochimica Acta 68 2591 - 2611 00167037 2004/06 [Refereed][Not invited]
     
    Amoeboid olivine aggregates (AOAs) from the reduced CV chondrites Efremovka, Vigarano, and Leoville consist of forsteritic olivine, FeNi-metal and a refractory component composed of spinel, Al-diopside, ±anorthite. Secondary ferrous olivine and alkali-rich minerals (nepheline and sodalite), commonly observed in the oxidized CVs, are rare. Mineralogy and chemical compositions of AOAs are similar to those predicted by equilibrium thermodynamic condensation models, suggesting that AOAs formed primarily by gas-solid condensation over a narrow temperature range, slightly below the temperatures over which most Ca-Al-rich inclusions (CAIs) formed. AOAs in the reduced CVs preserve a 1st- generation 16O-rich signal (δ17,18O ∼ -40‰) similar to that observed in many CAIs, suggesting that these refractory objects originated from a common source in the solar nebula. In fact AOAs and many fine-grained CAIs may have formed by the same processes, but at slightly different temperatures, and can be considered a single class of refractory objects. Alteration of the AOAs is manifested by differing extents of 16O- depletion in original AOA minerals, FeO-enrichment in olivine, and formation of interstitial very fine grained Na-bearing phases. From the six AOAs and one fine-grained, melilite-pyroxene-rich CAI examined in this study, five distinct patterns of alteration were identified. (1) One unaltered AOA from Vigarano is characterized by 16 O-rich forsterite without FeO-rich rims and interstitial Na-bearing phases. (2) Weak alteration in the melilite-pyroxene-rich CAI is characterized by incomplete 16O-depletion in some melilite and precipitation of Na-bearing phases near the CAI rim. (3) Oxygen isotopic composition and mineralogy are correlated in two AOAs from Leoville with 16O-rich olivine, 16O-poor anorthite and a range of intermediate compositions in Al-diopside. This pattern is consistent with model diffusion between original grains and a 16O-poor reservoir during a relatively short-term (<60 yr), high-temperature (900-1100°C) event. (4) Original forsterite has been enriched in FeO, but remained 16O-rich in one AOA from Vigarano. This result is consistent with the slower rate of diffusion of O than Fe and Mg in olivine. At least some interstitial phases are 16O-rich, and Na-bearing phases are abundant in this AOA. (5) In contrast, oxygen isotopic composition and Fo-content are correlated in two AOAs from Efremovka. The olivine in these AOAs tends to have forsteritic 16O-rich cores and FeO-rich 16O-depleted rims. The general correlation between oxygen isotopic composition and Fo-content is difficult to model by diffusion, and may have formed instead by aqueous dissolution and precipitation along the margins of preexisting olivine grains. Independent evidence for aqueous alteration of the Efremovka AOAs is provided by OH-rich signals detected during ion beam sputtering of some of the 16O-poor olivine. Elevated 16OH-count rates and order of magnitude increases in 16OH detected during single analyses reflect trapping of an aqueous phase in 16O-depleted olivine. An elevated 16OH signal was also detected in one analysis of relatively 16O-poor melilite in the melilite-pyroxene CAI from Vigarano, suggesting that this object also was altered by aqueous fluid. © 2004 Elsevier Ltd. All rights reserved.
  • Alexander N. Krot, Timothy J. Fagan, Klaus Keil, Kevin D. McKeegan, Sandeep Sahijpal, Ian D. Hutcheon, Mikhail I. Petaev, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 68 2167 - 2184 00167037 2004/05 [Refereed][Not invited]
     
    Based on their mineralogy and petrography, ∼200 refractory inclusions studied in the unique carbonaceous chondrite, Acfer 094, can be divided into corundum-rich (0.5%), hibonite-rich (1.1%), grossite-rich (8.5%), compact and fluffy Type A (spinel-melilite-rich, 50.3%), pyroxene-anorthite-rich (7.4%), and Type C (pyroxene-anorthite-rich with igneous textures, 1.6%) Ca,Al-rich inclusions (CAIs), pyroxene-hibonite spherules (0.5%), and amoeboid olivine aggregates (AOAs, 30.2%). Melilite in some CAIs is replaced by spinel and Al-diopside and/or by anorthite, whereas spinel-pyroxene assemblages in CAIs and AOAs appear to be replaced by anorthite. Forsterite grains in several AOAs are replaced by low-Ca pyroxene. None of the CAIs or AOAs show evidence for Fe-alkali metasomatic or aqueous alteration. The mineralogy, textures, and bulk chemistry of most Acfer 094 refractory inclusions are consistent with their origin by gas-solid condensation and may reflect continuous interaction with SiO and Mg of the cooling nebula gas. It appears that only a few CAIs experienced subsequent melting. The Al-rich chondrules (ARCs; > 10 wt% bulk Al2O3) consist of forsteritic olivine and low-Ca pyroxene phenocrysts, pigeonite, augite, anorthitic plagioclase, ± spinel, FeNi-metal, and crystalline mesostasis composed of plagioclase, augite and a silica phase. Most ARCs are spherical and mineralogically uniform, but some are irregular in shape and heterogeneous in mineralogy, with distinct ferromagnesian and aluminous domains. The ferromagnesian domains tend to form chondrule mantles, and are dominated by low-Ca pyroxene and forsteritic olivine, anorthitic mesostasis, and Fe,Ni-metal nodules. The aluminous domains are dominated by anorthite, high-Ca pyroxene and spinel, occasionally with inclusions of perovskite; have no or little FeNi-metal; and tend to form cores of the heterogeneous chondrules. The cores are enriched in bulk Ca and Al, and apparently formed from melting of CAI-like precursor material that did not mix completely with adjacent ferromagnesian melt. The inferred presence of CAI-like material among precursors for Al-rich chondrules is in apparent conflict with lack of evidence for melting of CAIs that occur outside chondrules, suggesting that these CAIs were largely absent from chondrule-forming region(s) at the time of chondrule formation. This may imply that there are several populations of CAIs in Acfer 094 and that mixing of "normal" CAIs that occur outside chondrules and chondrules that accreted into the Acfer 094 parent asteroid took place after chondrule formation. Alternatively, there may have been an overlap in the CAI- and chondrule-forming regions, where the least refractory CAIs were mixed with Fe-Mg chondrule precursors. This hypothesis is difficult to reconcile with the lack of evidence of melting of AOAs which represent aggregates of the least refractory CAIs and forsterite grains. © 2004 Elsevier Ltd.
  • Alexander N. Krot, Michail I. Petaev, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 68 1923 - 1941 00167037 2004/04 [Refereed][Not invited]
     
    Amoeboid olivine aggregates (AOAs) in primitive (unmetamorphosed and unaltered) carbonaceous chondrites are uniformly 16O-enriched (Δ17O ∼ -20‰) and consist of forsterite (Fa<2), FeNi-metal, and a refractory component (individual CAIs and fine-grained minerals interspersed with forsterite grains) composed of Al-diopside, anorthite, ±spinel, and exceptionally rare melilite (Åk<15); some CAIs in AOAs have compact, igneous textures. Melilite in AOAs is replaced by a fine-grained mixture of spinel, Al-diopside, and anorthite. Spinel is corroded by anorthite or by Al-diopside. In ∼10% of > 500 AOAs studied in the CR, CV, CM, CO, CH, CB, and ungrouped carbonaceous chondrites Acfer 094, Adelaide, and LEW85332, forsterite is replaced to a various degree by low-Ca pyroxene. There are three major textural occurrences of low-Ca pyroxene in AOAs: (i) thin (<10 μm) discontinuous layers around forsterite grains or along forsterite grain boundaries in AOA peripheries; (ii) haloes and subhedral grains around FeNi-metal nodules in AOA peripheries, and (iii) thick (up to 70 μm) continuous layers with abundant tiny inclusions of FeNi-metal grains around AOAs. AOAs with low-Ca pyroxene appear to have experienced melting of various degrees. In the most extensively melted AOA in the CV chondrite Leoville, only spinel grains are relict; forsterite, anorthite and Al-diopside were melted. This AOA has an igneous rim of low-Ca pyroxene with abundant FeNi-metal nodules and is texturally similar to Type I chondrules. Based on these observations and thermodynamic analysis, we conclude that AOAs are aggregates of relatively low temperature solar nebular condensates originated in 16O-rich gaseous reservoir(s), probably CAI-forming region(s). Some of the CAIs were melted before aggregation into AOAs. Many AOAs must have also experienced melting, but of a much smaller degree than chondrules. Before and possibly after aggregation, melilite and spinel reacted with the gaseous SiO and Mg to form Ca-Tschermakite (CaAl2SiO6)-diopside (CaMgSi2O6) solid solution and anorthite. Solid or incipiently melted olivine in some AOAs reacted with gaseous SiO in the CAI- or chondrule-forming regions to form low-Ca pyroxene: Mg2SiO4 + SiO(g) + H2O(g) = Mg2Si2O6 + H2(g). Some low-Ca pyroxenes in AOAs may have formed by oxidation of Si-bearing FeNi-metal: Mg2SiO4 + Si(inFeNi) + 2H2O(g) = Mg2 Si2O6 + 2H2(g) and by direct gas-solid condensation: Mg(g) + SiO(g) +H2 O(g) = Mg2Si2O6(s) + H2(g) from fractionated (Mg/Si ratio < solar) nebular gas. Although bulk compositions of AOAs are rather similar to those of Type I chondrules, on the projection from spinel onto the plane Ca2SiO4-Mg2SiO4- Al2O3, these objects plot on different sides of the anorthite-forsterite thermal divide, suggesting that Type I chondrules cannot be produced from AOAs by an igneous fractionation. Formation of low-Ca pyroxene by reaction of AOAs with gaseous SiO and by melting of silica-rich dust accreted around AOAs moves bulk compositions of the AOAs towards chondrules, and provide possible mechanisms of transformation of refractory materials into chondrules or chondrule precursors. The rare occurrences of low-Ca pyroxene in AOAs may indicate that either AOAs were isolated from the hot nebular gas before condensation of low-Ca pyroxene or that condensation of low-Ca pyroxene by reaction between forsterite and gaseous SiO was kinetically inhibited. If the latter is correct, then the common occurrences of pyroxene-rich Type I chondrules may require either direct condensation of low-Ca pyroxenes or SiO2 from fractionated nebular gas or condensation of gaseous SiO into chondrule melts. © 2004 Elsevier Ltd.
  • Nagashima K, Krot AN, Yurimoto H
    Nature 428 (6986) 921 - 924 1476-4687|0028-0836 2004/04 [Refereed][Not invited]
  • Andreas Pack, Hisayoshi Yurimoto, Herbert Palme
    Geochimica et Cosmochimica Acta 68 1135 - 1157 00167037 2004/03 [Refereed][Not invited]
     
    We have conducted petrographic, chemical and in-situ oxygen isotopic studies of refractory forsterites from unequilibrated ordinary and carbonaceous chondrites as well as an unequilibrated R-chondrite. Refractory forsterites occur in all types of unequilibrated chondrites and all have very similar chemical composition with low FeO and high refractory lithophile element (RLE) contents. Refractory forsterites are typically enriched in 16O relative to 'normal' olivine independent of the bulk O-isotope ratios of the parent meteorites. Analyses of refractory forsterites spread along a Δ17O mixing line with Δ17O ranging from +2 to -10‰. Due to similarities in oxygen isotopes and chemical compositions, we conclude that refractory forsterites of various types of chondrites come from a single common reservoir. Implications of this hypothesis for the chemical and O-isotope evolution of silicates in the early solar nebular are discussed. © 2004 Elsevier Ltd.
  • Tsuyoshi Komiya, Shigenori Maruyama, Takafumi Hirata, Hisayoshi Yurimoto, Susumu Nohda
    Island Arc 13 47 - 72 10384871 2004/03 [Refereed][Not invited]
     
    Recent geological investigations of the Isua Supracrustal Belt (3.8 Ga), southern West Greenland, have suggested that it is the oldest accretionary complex on earth, defined by an oceanic plate-type stratigraphy and a duplex structure. Plate history from mid-oceanic ridge through plume magmatism to subduction zone has been postulated from analysis of the reconstructed oceanic plate stratigraphy in the accretionary complex. Comparison between field occurrence of greenstones in modern and ancient accretionary complexes reveals that two types of tholeiitic basalt from different tectonic settings, mid-oceanic ridge basalt (MORB) and oceanic island basalt (OIB), occur. This work presents major, trace and rare earth element (REE) compositions of greenstones derived from Isua MORB and OIB, and of extremely rare relict igneous clinopyroxene in Isua MORB. The Isua clinopyroxenes (Cpx) have compositional variations equivalent to those of Cpx in modern MORB; in particular, low TiO2 and Na2O contents. The Isua Cpx show slightly light (L)REE-depleted REE patterns, and the calculated REE pattern of the host magma is in agreement with that of Isua MORB. Analyses of 49 least-altered greenstones carefully selected from approximately 1200 samples indicate that Isua MORB are enriched in Al2O3, and depleted in TiO2, FeO*, Y and Zr at the given MgO content, compared with Isua OIB. In addition, Isua MORB show an LREE-depleted pattern, whereas Isua OIB forms a flat REE pattern. Such differences suggest that the Early Archean mantle had already become heterogeneous, depending on the tectonic environment. Isua MORB are enriched in FeO compared with modern MORB. Comparison of Isua MORB with recent melting experiments shows that the source mantle had 85-87 in Mg# and was enriched in FeO. Potential mantle temperature is estimated to be approximately 1480°C, indicating that the Early Archean mantle was hotter by at most approximately 150°C than the modern mantle. © 2004 Blackwelll Publishing Asia Pty Ltd.
  • Shoichi Itoh, Hideyasu Kojima, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 68 183 - 194 00167037 2004/01 [Refereed][Not invited]
     
    Fine-grained Ca-Al-rich inclusions (FGIs) in Yamato-81020 (CO3.0) and Kainsaz (CO3.1-CO3.2) chondrites have been studied by secondary ion mass spectrometry. The FGIs from Yamato-81020 consist of aggregates of hibonite, spinel, melilite, anorthite, diopside and olivine grains with no petrographic evidence of alteration. In contrast, the FGIs from Kainsaz commonly contain alteration products such as nepheline. From replacement textures and chemical compositions of altered and unaltered FGIs, we conclude that the alteration products formed by decomposition of melilite and anorthite. All phases in the Yamato-81020 FGIs are enriched in 16O, with δ17,18O = ∼-40‰ except for one FGI that experienced melting. Oxygen isotopic compositions of melilite, anorthite, some spinel and diopside in Kainsaz FGIs changed from δ17,18O = ∼-40‰ toward 0‰ by aqueous alteration. Alteration products in FGIs are depleted in 16O relative to primary phases, with δ17,18O = ∼0‰. These results show that FGIs in CO chondrites commonly had 16O-rich compositions in the solar nebula. The original 16O-rich FGIs were modified to 16O-poor compositions during aqueous alteration in the parent body. © 2004 Elsevier Ltd.
  • Sachio Kobayashi, Hajime Imai, Hisayoshi Yurimoto
    Geochemical Journal 37 663 - 669 00167002 2003/12 [Refereed][Not invited]
     
    An enrichment of oxygen-16 of about 8% relative to the Earth has been found in a chondrule from the Acfer 214 carbonaceous chondrite. In contrast, isotopic abundances of major cations, Mg and Si, are similar to those of the Earth. These suggest that oxygen isotopic heterogeneity in the early solar system was much larger ever thought and assist mass-independent-isotopic fractionation for the origin. Because the chondrule has solar abundance for refractory and normal lithophile elements, we propose that silicate dusts in the early solar system were initially enriched in 16O corresponding to the 16O-rich reservoir.
  • Ikuo Katayama, Kei Hirose, Hisayoshi Yurimoto, Satoru Nakashima
    Geophysical Research Letters 30 00948276 2003/11 [Refereed][Not invited]
     
    Water in majoritic garnet synthesized in the mid-oceanic ridge basalt (MORB) + H2O composition at 20 GPa and 1400-1500°C was measured by secondary ion mass spectrometry (SIMS) and infrared spectroscopy. We found that the majorite contains 1130 to 1250 ppm OH by weight. The infrared absorption band showed that incorporation of the hydroxyl in majorite is most likely due to the hydrogarnet substitution. Our results indicate that water can be transported into the mantle transition zone by nominally anhydrous minerals such as omphacite and majorite in the subducting basaltic crust. Such water may have great influences on the physical properties of slab in the transition zone.
  • Seiji Maruyama, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 67 3943 - 3957 00167037 2003/10 [Refereed][Not invited]
     
    The petrological properties, and O and Al-Mg isotopic compositions of two spinel-bearing chondrules from the Allende CV chondrite were investigated using scanning electron microscopy and secondary ion mass spectrometry. A coarse spinel grain in a barred-olivine (BO) chondrule is less enriched in 16O (Δ17O ∼ -5‰; Δ17O = δ17O - 0.52 δ18O), whereas smaller spinel grains in a plagioclase-rich chondrule member of a compound chondrule are extremely 16O-rich (Δ17O ∼ -17‰) and the spinels have a strongly serrated character. The petrological features and 16O-enrichments of the spinels in the plagioclase-rich chondrule indicate that spinels originating in coarse-grained Ca-Al-rich Inclusions (CAIs) were incorporated into chondrule precursors and survived the chondrule-forming event. The degree of 16O-excesses among minerals within each chondrule is correlated to the crystallization sequences. This evidence suggests that the O isotopic variation among minerals may have resulted from incomplete exchange of O isotopes between 16O-rich chondrule melt and 16O-poor nebular gas. Aqueous alteration also has changed the O-isotope compositions in the mesostasis. The feldspathic mesostasis in the BO chondrule shows a disturbed Mg-Al isochron indicating that the BO chondrule experienced secondary alteration. While plagioclase in the plagioclase-rich chondrule member of the compound chondrule shows slight 26Mg-excesses corresponding to (26Al/27Al)0 = [4.6±4.0(2σ)] × 10-6, nepheline formed by secondary alteration shows no detectable excess. The Al-Mg isotopic system of these chondrules was disturbed by aqueous alteration and thermal metamorphism on the Allende parent body. Copyright © 2003 Elsevier Ltd.
  • Yasuhiko Ohara, Kantaro Fujioka, Teruaki Ishii, Hisayoshi Yurimoto
    Geochemistry, Geophysics, Geosystems 4 15252027 2003/07 [Refereed][Not invited]
     
    Peridotite samples from a backarc basin setting will help better understand global mid-oceanic ridge processes. Here we report detailed petrological data of serpentinized peridotite and gabbro from the extinct Parece Vela Basin in the Philippine Sea. Despite its relatively fast spreading rate (8.8-7.0 cm/y full-rate), the Parece Vela Basin spreading ridge (the Parece Vela Rift) has the distinct morpho-tectonic characteristics that indicate a small degree of mantle melting, including the presence of a huge mullion structure (the Godzilla Mullion). Peridotites in the Parece Vela Rift are exposed on the Godzilla Mullion as well as at a segment midpoint. The most notable characteristic of Parece Vela Rift peridotites is small-scale juxtaposition (i.e., a single-dredge-haul scale) of fertile peridotite and depleted peridotite (dunite and plagioclase-bearing peridotite). We interpret that the fertile peridotite (F-type) is the residue of a small degree of mantle melting (̃4% near-fractional melting of a MORB-type mantle), whereas dunite (D-type) and plagioclase-bearing peridotite (P-type) are products of melt-mantle interaction. The associated evolved gabbros may represent the shallow level fractionated melt intruded into P-type. The distinct morphotectonic characteristics, peridotite exposure at a segment midpoint, and the presence of fertile peridotite may result from an extreme transform fault effect caused by the ridge-transform geometry of short firstorder segments sandwiched by closely spaced fracture zones ("transform sandwich effect"). © 2003 by the American Geophysical Union.
  • Konstantin Litasov, Eiji Ohtani, Falko Langenhorst, Hisayoshi Yurimoto, Tomoaki Kubo, Tadashi Kondo
    Earth and Planetary Science Letters 211 189 - 203 0012821X 2003/06 [Refereed][Not invited]
     
    The water storage capacity of the major constituent of the lower mantle, Mg-perovskite, is a matter of debate. Here we report water solubility of Mg-perovskites with different compositions observed in peridotite and MORB systems. IR spectra of pure MgSiO3-perovskite show bands at 3397, 3423, 3448, and 3482 cm-1 and suggest about 100 ppm H2O. The H2O content in Al-Mg-perovskite (4-7 wt% Al2O3; Mg#=100) is 1000-1500 ppm (major band at 3448 cm-1), whereas Al-Fe-Mg-perovskite in MORB (Al2O3=13-17 wt%; Mg#=58-61) contains 40-110 ppm H2O (major band at 3397 cm-1). The H2O content in Al-Fe-Mg-perovskite observed in peridotite (Al2O3=5-6 wt%; Mg#=88-90) is 1400-1800 ppm (major band at 3397 cm-1). Al-Fe-Mg-perovskite from the MORB system has a high Fe3+ content, Fe3+/∑Fe=0.6, determined by electron energy loss spectroscopy measurements. Water can enter into the perovskite structure with oxygen vacancies originating from the substitution of Si by Al and Fe3+. Oxygen vacancy incorporation is favored for aluminous perovskite synthesized from the MgO-rich peridotite system. The substitution of Si4++Mg2+=2(Al,Fe)3+ prevails however in the Al-Fe-Mg-perovskite from the MORB system (MgO-poor, Al- and Fe-rich), explaining its restricted water solubility. The maximum amount of water stored in the lower mantle is estimated to be 3.42×1021 kg, which is 2.5 times the present ocean mass. Comparison of the phase relations in hydrous pyrolite and hydrous MORB indicates that pyrolite is more important as water container and water carrier in the mantle. Pyrolite contains: (1) dense hydrous magnesium silicates, existing under conditions of subducting slabs, and (2) hydrous wadsleyite, hydrous ringwoodite and water-bearing perovskite under the normal mantle and hotter conditions. Distribution of water to the MORB is restricted at the conditions of the transition zone and lower mantle. © 2003 Elsevier Science B.V. All rights reserved.
  • Itoh S, Yurimoto H
    Nature 423 (6941) 728 - 731 1476-4687|0028-0836 2003/06 [Refereed][Not invited]
  • Hajime Imai, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 67 765 - 772 00167037 2003/02 [Refereed][Not invited]
     
    The oxygen isotopic distribution in an amoeboid olivine aggregate (AOA), TTA1-02, from the Allende CV3 chondrite has been determined by secondary ion mass spectrometry. The irregular shaped TTA1-3mm) consists mostly of olivine grains of ca.μ in diameter. Olivine grains of Mg-rich (Fo95) and Fe-rich (Fo60) composition are in direct contact with each other, with a sharp compositional boundary. Oxygen isotopic compositions of Fe-rich olivine grains are 16O-poor (Δ17O ≅ -5‰) whereas Mg-rich olivine is 16O-rich (Δ17O ≅ -25‰).Several Al-rich inclusions (
  • Hisayoshi Yurimoto, Kazuhide Nagashima, Takuya Kunihiro
    Applied Surface Science 203-204 793 - 797 01694332 2003/01 [Refereed][Not invited]
     
    Secondary ion mass spectrometry (SIMS) is widely used to identify the isotope ratio of the micro-area of materials. We demonstrate that the precision and spatial resolution of an ion microscope using SIMS coupled with a newly developed solid-state ion imager can be extended to two-dimensional isotope ratio imaging with permil-precision. An isotopic map for oxygen clearly reveals the distribution of 4% enrichment of 16O in spinel particles embedded in melilite from a Ca-Al-rich inclusion of a carbonaceous chondrite. This characterization technique called isotopography thus provides the eyes to see small heterogeneity of isotope abundance in micro-scale. It is likely to find broad application in earth, material, and life science research. © 2002 Elsevier Science B.V. All rights reserved.
  • Isao Takayanagi, Junichi Nakamura, Eric R. Fossum, Kazuhide Nagashima, Takuya Kunihoro, Hisayoshi Yurimoto
    IEEE Transactions on Electron Devices 50 70 - 76 00189383 2003/01 [Refereed][Not invited]
     
    A stacked CMOS-active pixel sensor (APS) with a newly devised pixel structure for charged particle detection has been developed. At low operation temperatures (<200K), the dark current of the CMOS-APS is determined by the hot carrier effect. A twin well CMOS pixel with a p-MOS readout and n-MOS reset circuit achieves low leakage current as low as 5 × 10-8 V/s at the pixel electrode under liquid nitrogen temperature of 77 K. The total read noise floor of 0.1 mVrms at the pixel electrode was obtained by nondestructive readout correlated double sampling (CDS) with the CDS interval of 21 s.
  • Hisayoshi Yurimoto, John T. Wasson
    Geochimica et Cosmochimica Acta 66 4355 - 4363 00167037 2002/12 [Refereed][Not invited]
     
    We describe a phenocryst in a CO-chondrite type-II chondrule that we infer to have formed by melting an amoeboid olivine aggregate (AOA). This magnesian olivine phenocryst has an extremely16O-rich composition Δ17O (=δ17O - 0.52 · δ18O) = -23‰. It is present in one of the most pristine carbonaceous chondrites, the CO3.0 chondrite Yamato 81020. The bulk of the chondrule has a very different Δ17O of -1‰, thus the Δ17O range within this single chondrule is 22‰, the largest range encountered in a chondrule. We interpret the O isotopic and Fe-Mg distributions to indicate that a fine-grained AOA assemblage was incompletely melted during the flash melting that formed the chondrule. Some Fe-Mg exchange but negligible O-isotopic exchange occurred between its core and the remainder of the chondrule. A diffusional model to account for the observed Fe-Mg and O-isotopic exchange yields a cooling rate of 105to 106K hr-1. This estimate is much higher than the cooling rates of 101to 103K hr-1inferred from furnace simulations of type-II chondrule textures (e.g. Lofgren, 1996); however, our cooling-rate applies to higher temperatures (near 1900 K) than are modeled by the crystal-growth based cooling rates. We observed a low26Al/27Al initial ratio ((4.6 ± 3.0) · 10-6) in the chondrule mesostasis, a value similar to those in ordinary chondrites (Kita et al., 2000). If the26Al/27Al system is a good chronometer, then chondrule I formed about 2 Ma after the formation of refractory inclusions. Copyright © 2002 Elsevier Science Ltd.
  • Guk Lac Kim, Guk Lac Kim, Hisayoshi Yurimoto, Shigeho Sueno
    Journal of Mineralogical and Petrological Sciences 97 (4) 161 - 167 1349-3825|1345-6296 2002/12 [Refereed][Not invited]
     
    A calcium-aluminum-rich inclusion (CAI) containing big palisade bodies was found within the Allende meteorite. The bulk composition and mineral assemblages show that the CAI belongs to coarse-grained Type B. Oxygen isotopic distributions in palisade bodies in the CAI are similar to those observed in typical Type B CAIs, whereas all minerals including melilite in the host parts are enriched in 16 O. The oxygen isotopic distribution in the CAI indicates that exchange of oxygen isotopes in the palisade bodies occurred before the trapping of palisades into the host. The palisade bodies were formed separately as small CAIs in the solar nebula and then accumulated together to form a large CAI. This suggests the possibility that during the CAI formation, O isotopic environment of CAI-forming region in the solar nebula repeatedly changed from 16 O-rich to 16 O-poor.
  • Tsuyoshi Komiya, Mamoru Hayashi, Shigenori Maruyama, Hisayoshi Yurimoto
    American Journal of Science 302 (9) 806 - 826 0002-9599|1945-452X 2002/11 [Refereed][Not invited]
     
    The Isua supracrustal belt (ISB) rocks are dated at about 3.8 Ga and constitute the oldest accretionary complex in the world. Petrochemical and geothermobarometric studies of over 1,500 rock samples in ISB enabled us to estimate the extent of regional metamorphism, petrotectonic environment and subduction- zone geothermal gradient in the Archean. The following lines of evidence indicate the first discovery of progressive, prograde metamorphism from greenschist (Zone A) through Ab-Ep-amphibolite (Zone B) to amphibolite facies (Zones C and D) in the northeast part of the Isua supracrustal belt: (1) systematic change of mineral paragenesis in metabasites and metapelites; (2) progressive change of composition of major metamorphic minerals, including plagioclase, amphibole, chlorite, epidote, and garnet; (3) normal zoning of amphibole and garnet; and (4) absence of any vestige of high-grade metamorphism even in the lowest metamorphic zone. Geology and chronological constraints of ISB indicate that the regional metamorphism was related to the subduction of Archean lithosphere. Metamorphic pressures and temperatures of the metamorphism are estimated to be 5 to 7 kbar from Grt-Hbl-Pl-Qz geobarometry and 380° to 550°C from the Grt-Bt geothermometry in Zones B to D. These P-T estimates indicate that ISB was affected by progressive metamorphism of an intermediate P/T ratio metamorphic facies series, and that it records a much higher geothermal gradient of a subduction zone in the Archean than is known from the Phanerozoic. The high geothermal gradient may have resulted from the subduction of young lithosphere and a high potential temperature of mantle. The Archean high geothermal gradient led to melting of thick oceanic crust in a thin oceanic plate, creating many huge granitic (tonalite, trondhjemite, and granodiorite) batholiths. The slab melting changed the oceanic crust (density = 3.07) into a denser Grt-bearing residue (density = 3.55), implying that TTG melt extraction provided a potential driving force for Archean plate tectonics. In addition to the preservation of the oldest accretionary complex, this suggests that Precambrian-type plate tectonics, whose driving force is slab-pull due to densification of the residue of oceanic crust as a consequence of slab melting, was already operating in the Early Archean. The transition from Precambrian-type to Phanerozoic-type plate tectonics may be caused by thinning of oceanic crust and thickening of oceanic lithosphere in the late Archean, due to decrease of mantle temperature.
  • Jiuhua Chen, Toru Inoue, H. Yurimoto, Donald J. Weidner
    Geophysical Research Letters 29 22 - 1 00948276 2002/09 [Refereed][Not invited]
     
    The phase boundary between San Carlos olivine and its high pressure phase, wadsleyite, have been studied comparatively in dry and water saturated condition. By comparing saturated and dry samples from the same experimental run, we determine that both boundaries of the two-phase coexisting loop shift towards lower pressure or lower iron content, and the pressure width of the loop decreases to 0.3 GPa under saturated conditions at 1473 K. Thus, the presence of water in the Earth's mantle will sharpen the 410-kilometer seismic discontinuity, shallow the depth of the discontinuity, and reduce the velocity jump across the discontinuity.
  • Yuichiro Ueno, Hisayoshi Yurimoto, Hideyoshi Yoshioka, Tsuyoshi Komiya, Shigenori Maruyama
    Geochimica et Cosmochimica Acta 66 (7) 1257 - 1268 0016-7037 2002/04 [Refereed][Not invited]
     
    In-situ ion microprobe measurements of carbon isotopic compositions of graphite were made in seven metasediments and two carbonate rocks from the ca. 3.8 Ga Isua supracrustal belt, West Greenland. The δ 13 C values of micron-scale graphite globules in the metasediments and the carbonate rocks vary from -18 to +2‰ and from -7 to -3‰, respectively. The maximum δ 13 C value of graphite globules in the metasediment rises from -14 to -5‰, as the metamorphic grade increases from epidote-amphibolite to upper amphibolite facies. In a single hand specimen, the δ 13 C values of graphite inclusions in garnet are ~7‰ lower on average than those outside garnet. Similarly, graphite armored by quartz apparently shows a few permil lower δ 1 3C values than those on grain boundaries between noncarbonate minerals. The fact that early crystallized minerals include relatively 13 C-depleted graphite indicates that the regional metamorphism increased the δ 1 3C values of the Isua graphite. This is consistent with the regional trend of 13 C-enrichment accompanied by the increase of metamorphic grade. The minimum fractionation between graphite and carbonate is consistent with the equilibrium fractionation at about 400 to 550 °C. These observations indicate that isotopic exchange with isotopically heavy carbonate caused 13 C-enrichment of Isua graphite. The δ 13 C values of graphite reported here (δ 13 C > -18‰) were produced either as a metamorphic modification of organic carbon with initially much lower δ 13 C values, or as an abiological reaction such as decomposition of carbonate. If the isotopic exchange between carbonate and graphite during the regional metamorphism controlled the 1 3C-enrichment of Isua graphite, previously reported large 13 C-depletion of graphite, especially armored by apatite (Mojzsis et al., 1996) was probably premetamorphic in origin. This supports the existence of life at Isua time (ca. 3.8 Ga). Copyright © 2002 Elsevier Science Ltd.
  • Murakami M, Hirose K, Yurimoto H, Nakashima S, Takafuji N
    Science (New York, N.Y.) 295 (5561) 1885 - 1887 0036-8075|1095-9203 2002/03 [Refereed][Not invited]
  • Yasuhiko Ohara, Robert J. Stern, Teruaki Ishii, Hisayoshi Yurimoto, Toshitsugu Yamazaki
    Contributions to Mineralogy and Petrology 143 (1) 1 - 18 1432-0967|0010-7999 2002/01 [Refereed][Not invited]
     
    Two dives of the DSV Shinkai 6500 in the Mariana Trough back-arc basin in the western Pacific sampled back-arc basin mantle exposures. Reports of peridotite exposures in back-arc basin setting are very limited and the lack of samples has hindered our understanding of this important aspect of lithospheric evolution. The Mariana Trough is a slow-spreading ridge, and ultramafic exposures with associated gabbro dykes or sills are located within a segment boundary. Petrological data suggest that the Mariana Trough peridotites are moderately depleted residues after partial melting of the upper mantle. Although some peridotite samples are affected by small-scale metasomatism, there is no evidence of pervasive post-melting metasomatism or melt-mantle interaction. Spinel compositions plot in the field for abyssal peridotites. Clinopyroxenes show depletions in Ti, Zr, and REE that are intermediate between those documented for peridotites from the Vulcan and Bouvet fracture zones “the American-Antarctic and Southwest Indian ridges, respectively”. The open-system melting model indicates that the Mariana Trough peridotite compositions roughly correspond to theoretical residual compositions after ∼ 7% near-fractional melting of a depleted MORB-type upper mantle with only little melt or fluid/mantle interactions. The low degree of melting is consistent with a low magma budget, resulting in ultramafic exposure. We infer that the mantle flow beneath the Mariana Trough Central Graben is episodic, resulting in varying magma supply rate at spreading segments.
  • Tsuyoshi Komiya, Shigenori Maruyama, Takafumi Hirata, Hisayoshi Yurimoto
    International Geology Review 44 988 - 1016 00206814 2002/01 [Refereed][Not invited]
     
    It is necessary and important to determine the tectonic setting of mafic volcanism, because compositions of magma are strongly related to tectonic setting. Our recent geological investigation of the North Pole (NP) region (3.5 Ga), Pilbara, showed that the greenstone belt was an accretionary complex, defined by oceanic-plate stratigraphy and duplex structure. Moreover, application of accretionary geology reveals that there are two types of tholeiitic basalts from different tectonic settings: midocean ridge (MORB) and oceanic island (OIB). This work presents geochemistry of major, trace, and rare-earth elements (REE) of greenstones originating as MORB and OIB in the mid-Archean. Relict igneous clinopyroxenes (Cpx) in NP MORB and OIB have compositional variations equivalent to chemical variations of Cpx in modern MORB and OIB. In addition, TiO 2 content and Mg # = (MgO/(MgO+FeO*)) in the host magma calculated from those in Cpx are consistent with whole-rock compositions, indicating preservation of original compositions in terms of TiO 2 , FeO, and MgO contents. The Cpx in NP MORB and OIB show LREE-depleted and slightly LREE-depleted REE patterns, respectively. Calculated REE patterns of host magmas also are in agreement with the wholerock compositions. Analyses of 64 alteration-free greenstones selected from 2662 samples indicate that NP MORB is enriched in Al 2 O 3 and depleted in TiO 2 , FeO*, Y, and Zr at any MgO content, compared with NP OIB. In addition, NP MORB show a slightly LREE-depleted, whereas NP OIB forms a slightly LREE-enriched REE patterns. Such differences suggest that the Archean mantle already was differentiated. However, the compositional difference between the source mantles is relatively small, and differentiation into MORB and OIB source mantles was in the process of development. NP MORB are enriched in FeO, compared with modern MORB. Comparison of NP MORB with recent melting experiments shows that the source mantle of the NP MORB had Mg # = 85-87 and was enriched in FeO relative to the modern upper mantle. A possible mechanism to decrease the FeO content in the mantle is precipitation of metallic iron at the point of slab penetration into the lower mantle through time. The potential temperature of the source mantle of NP MORB is estimated to be ~1500 °C, indicating that even the mid-Archean mantle was hotter by at most ~150-200°C than the modern mantle, in contrast to the estimate from peridotitic komatiites. © 2002 Taylor & Francis Group, LLC.
  • Shoji Arai, Megumi Kida, Natsue Abe, Hisayoshi Yurimoto
    Journal of Mineralogical and Petrological Sciences 96 (3) 89 - 99 1349-3825|1345-6296 2001/12 [Refereed][Not invited]
     
    Peridotite xenoliths in alkali basalt of about 11.0 Ma in age from Boun, which erupted in the Ogcheon belt, a tectonic belt between the Sino-Korean and Yangtze cratons, are examined to understand the petrological nature of the upper mantle beneath the Korean Peninsula. The xenolithic suite is almost composed of lherzolite containing spinel of low Cr# [=Cr/(Cr+Al) atomic ratio] around 0.1, and clinopyroxene with relatively high Na 2 O content (about 1 to 2 wt%). Predominance of the fertile lherzolite within the mantle may indicate that appreciable amount of melts did not pass through it and not leave dunite and/or pyroxenites with aureole of restite with higher degree of melting. The lherzolite from Boun has mineralogical characteristics of continental rift-zone mantle peridotite and is distinctly different from sub-arc and abyssal mantle peridotites. It is noteworthy that the peridotite xenoliths with arc or abyssal mantle signatures apparently have not been found from the eastern margin of the Asian continent, including the Korean Peninsula, despite possible arc settings experienced through geologic time. It is highly speculative but is possible that the arc-type mantle material had not been accreted upon arc crust accretion. Alternatively the arc type mantle which had once been present beneath the continental margin was replaced later by the continental rift-zone type mantle.
  • John T. Wasson, Hisayoshi Yurimoto, Sara S. Russell
    Geochimica et Cosmochimica Acta 65 (24) 4539 - 4549 0016-7037 2001/12 [Refereed][Not invited]
     
    A problem of long-standing is the origin of the high Δ 17 O (= δ 17 O - 0.52 - δ 18 O) values of melilite in the refractory inclusions of carbonaceous chondrites. The spinel and, usually, also the diopside in the inclusions have "primitive" Δ 17 O ≤ - 20‰, but in the widely studied CV3 chondrite Allende, the melilite commonly has a Δ 17 O of about -4±2‰. Recent studies of oxygen diffusion coefficients in melilite and spinel have shown that the traditional model for altering the melilite-diffusive exchange with the gas in the solar nebula-cannot occur under plausible nebular scenarios. Because of increasing evidence for aqueous alteration of Allende and other carbonaceous chondrites, we tested the hypothesis that melilite alteration might occur during aqueous alteration by studying melilite in CO chondrites showing variable degrees of alteration. Our results show that almost all melilite in CO3.2 Kainsaz and CO3.3 Ornans has Δ 17 O > -15‰, whereas in CO3.0 Colony (and inclusions in CO3.0 Yamato 81020 studied by Itoh et al. [2000]) Δ 17 O in the melilite is < -20‰ (with the exception of one unusual inclusion that has undergone two melting episodes). We suggest that the O-isotopic composition of the melilite is reset by dissolution of the primitive melilite and reprecipitation in the presence of H 2 O having a high Δ 17 O value similar to that inferred from studies of CV magnetite (Choi et al., 1997, 2000). Although alteration of melilite can produce phases such as nepheline, andradite, and hedenbergite, it appears that, depending on the composition of the microenvironment, melilite present in a high-energy state (because of fine grain size, dislocations, other defects) can dissolve and reprecipitate with an O-isotopic composition intermediate between the initial composition and that of the H 2 O. A possible implication of our study is that the slope ≈0.9 arrays observed in the minerals of refractory inclusions of many carbonaceous chondrites could be mainly the result of aqueous alteration. Copyright © 2001 Elsevier Science Ltd.
  • Yuji Higo, Toru Inoue, Tetsuo Irifune, Hisayoshi Yurimoto
    Geophysical Research Letters 28 (18) 3505 - 3508 0094-8276|1944-8007 2001/09 [Refereed][Not invited]
     
    The phase boundary between ringwoodite and perovskite plus periclase in Mg 2 SiO 4 was determined at 1600 °C under hydrous conditions with 1~3 wt% H 2 O. We found that the boundary moved to high-pressure side by ~0.2 GPa in these hydrous conditions compared with that in anhydrous condition. The SIMS measurements confirmed that the ringwoodite in hydrous condition contained a significant amount (~1 wt%) of water, whereas the perovskite accepted only very little (~0.05 wt%) water in its crystal structure. The discrepancy between the pressure of 660 km seismic discontinuity and that of the postspinel transformation reported in a recent in situ x-ray study is not explained by the effect of water on the transformation.
  • Takuya Kunihiro, Kazuhide Nagashima, Isao Takayanagi, Junichi Nakamura, Koji Kosaka, Hisayoshi Yurimoto
    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 470 (3) 512 - 519 0168-9002|1872-9576 2001/09 [Refereed][Not invited]
     
    The noise characteristics of a stacked CMOS active pixel sensor (SCAPS) for incident charged particles have been analyzed under 4.5 keV Si + ion irradiation. The source of SCAPS dark current was found to change from thermal to electron leakage with decreasing device temperature. Leakage current at charge integration part in a pixel has been reduced to 0.1electronss -1 at 77K. The incident ion signals are computed by subtracting reset frame values from each frame using a non-destructive readout operation. With increase of irradiated ions, the dominant noise source changed from read noise, and shot noise from the incident ions, to signal frame fixed-pattern noise from variations in sensitivity between pixels. Pixel read noise is equivalent to ten incident ions. The charge of an incident ion is converted to 1.5electrons in the pixel capacitor. Shot noise corresponds to the statistical fluctuation of incident ions. Signal frame fixed-pattern noise is 0.7% of the signal. By comparing full well conditions to noise floor, a dynamic range of 80dB is achieved. SCPAS is useful as a two-dimensional detector for microanalyses such as stigmatic secondary ion mass spectrometry. © 2001 Elsevier Science B.V. All rights reserved.
  • Kazuhide Nagashima, Takuya Kunihiro, Isao Takayanagi, Junichi Nakamura, Koji Kosaka, Hisayoshi Yurimoto
    Surface and Interface Analysis 31 (2) 131 - 137 1096-9918|0142-2421 2001/02 [Refereed][Not invited]
     
    A stacked CMOS-type active pixel sensor (SCAPS) for charged particles has been developed. The SCAPS is an integral-type detector that has several advantages over conventional systems, including two-dimensional detection, wide dynamic range, no insensitive time, direct detection of charged particles and a high degree of robustness. The output characteristics of the SCAPS for incident charged particles has been analysed both theoretically and experimentally. The relationships between the output voltage of the SCAPS and the number of incident charged particles were formulated by including corrections for the non-ideal characteristics of transistors in a pixel. The fluctuation of output characteristics of the SCAPS was evaluated experimentally by irradiation of secondary 4.5 keV Si + ions generated by SIMS. The function was used to determine the number of incident ions into each SCAPS pixel within twice the statistical error. The SCAPS is useful as a two-dimensional detector for microanalysis, such as stigmatic SIMS. Copyright © 2001 John Wiley & Sons, Ltd.
  • Isao Takayanagi, Junichi Nakamura, El Sayed Eid, Eric R. Fossum, Kazuhide Nagashima, Takuya Kunihiro, Hisayoshi Yurimoto
    Technical Digest-International Electron Devices Meeting 551 - 554 01631918 2001/01 [Refereed][Not invited]
     
    A stacked CMOS-active pixel sensor (APS) with a newly devised pixel structure for charged particle detection has been developed. A twin well pixel with a p-MOS readout transistor achieves low leakage current caused by a hot carrier effect at low temperature as low as 5×10 -8 V/s at the pixel electrode. The total read noise floor of 0.1mVrms was obtained by non-destructive readout CDS with the CDS interval of 21 seconds.
  • Hiroshi Taura, Hiroshi Taura, Hisayoshi Yurimoto, Takumi Kato, Takumi Kato, Shigeho Sueno
    Physics of the Earth and Planetary Interiors 124 (1/2) 25 - 32 0031-9201 2001/01 [Refereed][Not invited]
     
    Determination of partition coefficients for Mg- and Ca-perovskite/melt has been performed for 27 trace elements by combination of high pressure-temperature experiments using a multi-anvil apparatus and in situ trace element analysis by secondary ion mass spectrometry (SIMS). Each of the crystallographic sites for the perovskites gives rise to a parabola-shaped peak on the partition coefficient versus ionic radius diagram. This suggests that the elemental partitioning is governed by the structural control even under the lower mantle condition. On the diagrams for Mg- and Ca-perovskites, sharpness and peak position of peaks are consistent with geometrical flexibility of the corresponding coordination polyhedra. The relative height between the partition curves for homovalent ions is controlled by electrostatic charge balancing among their crystallographic sites. Large partition coefficients of Th and U in Ca-perovskite suggest that these elements play an important role for the heat source in the Earth's lower mantle. © 2001 Elsevier Science B.V. All rights reserved.
  • Yuichiro Ueno, Yukio Isozaki, Hisayoshi Yurimoto, Shigenori Maruyama
    International Geology Review 43 196 - 212 00206814 2001/01 [Refereed][Not invited]
     
    New types of carbonaceous filamentous microstructures have been identified in silica veins at two new localities in the ˜3.5 Ga North Pole area of Western Australia. Their carbon isotopic compositions were measured in situ by secondary-ion mass spectrometry. The carbonaceous filaments are ˜1 μm wide, 10 to 100 μm long, and are permineralized in a fine-grained (˜1 μm) silica matrix. They are morphologically divided into three types (i.e., spiral, thread-like, and branched filaments). Their sizes and morphologies resemble modern and previously reported fossil bacteria. These similarities and their complex three-dimenstional geometry suggest that they may represent morphologically preserved fossil bacteria. δ 13 C values of the carbonaceous filaments range from -42 to -32‰, which strongly suggest that they are composed of biologically fixed organic compounds, possibly via the reductive acetyl-CoA pathway or the Calvin cycle. This is consistent with the hypothesis that autotrophs already existed on the Archean Earth.
  • Wuyi Wang, Shigeho Sueno, Eiichi Takahashi, Hisayoshi Yurimoto, Tibor Gasparik
    Contributions to Mineralogy and Petrology 139 (6) 720 - 733 1432-0967|0010-7999 2000/12 [Refereed][Not invited]
     
    Trace element concentrations of peridotitic garnet inclusions in diamonds from two Chinese kimberlite pipes were determined using the ion microprobe. Garnet xenocrysts from the same two kimberlite pipes were also analyzed for comparison. In contrast to their extremely refractory major element compositions, all harzburgitic garnets showed enrichment in light rate earth elements (REE) relative to chondrite, resulting in sinuous REE patterns. Both normal and sinuous REE patterns were observed from the lherzolitic garnets. Concentrations of REE in garnets changed significantly from diamond to diamond and no specific correlations were observed with their major element compositions. Analyses of randomly selected two to three points within every grain of a large number of garnet inclusions by the ion microprobe demonstrated that there was no evident compositional heterogeneity, and multiple grains of one phase from a single diamond host also exhibit very similar compositions. This implies that the trace element heterogeneity within one grain or among multiple inclusions from the same diamond host, as reported from Siberian diamonds, is not a common feature for these Chinese diamonds. Concentrations of Na, Ti, and Zr tend to decrease when garnets become more refractory, but variations of Sr and Li are more complex. Compositions rich in light REE and relatively poor in high field strength elements (HFSE) of the harzburgitic garnet inclusions in diamonds are generally consistent with metasomatism by carbonatite melts. The trace element features observed from the garnet inclusions in Chinese diamonds may be caused by carbonatite melt infiltration and partial melt extraction. Spatial and temporal gradients in melt/rock ratio and temperature are the main reasons for the large variations of REE patterns and other trace element concentrations.
  • E. Ohtani, H. Mizobata, H. Yurimoto
    Physics and Chemistry of Minerals 27 (8) 533 - 544 0342-1791|1432-2021 2000/10 [Refereed][Not invited]
     
    We conducted high-pressure phase equilibrium experiments in the systems MgSiO 3 with 15 wt% H 2 O and Mg 2 SiO 4 with 5 wt% and 11 wt% H 2 O at 20 ~ 27 GPa. Based on the phase relations in these systems, together with the previous works on the related systems, we have clarified the stability relations of dense hydrous magnesium silicates in the system MgO-SiO 2 -H 2 O in the pressure range from 10 to 27 GPa. The results show that the stability field of phase G, which is identical to phase D and phase F, expands with increasing water contents. Water stored in serpentine in the descending cold slabs is transported into depths greater than 200 km, where serpentine decomposes to a mixture of phase A, enstatite, and fluid. Reaction sequences of the hydrous phases which appear at higher pressures vary with water content. In the slabs with a water content less than about 2 wt%, phase A carries water to a depth of 450 km. Hydrous wadsleyite, hydrous ringwoodite, and ilmenite are the main water reservoirs in the transition zone from 450 to 660 km. Superhydrous phase B is the water reservoir in the uppermost part of the lower mantle from 670 to 800 km, whereas phase G appears in the lower mantle only at depths greater than 800 km. In cold slabs with local water enrichment greater than 2 wt%, the following hydrous phases appear with increasing depths; phase A to 450 km, phase A and phase G from 450 km to 550 km, brucite, superhydrous phase B, and phase G from 550 km to 800 km, and phase G at depths greater than 800 km.
  • Daisuke Yamazaki, Takumi Kato, Hisayoshi Yurimoto, Eiji Ohtani, Mitsuhiro Toriumi
    Physics of the Earth and Planetary Interiors 119 299 - 309 00319201 2000/05 [Refereed][Not invited]
     
    Silicon self-diffusion coefficients in MgSiO 3 perovskite were measured under lower mantle conditions. The MgSiO 3 perovskite was synthesized and diffusion annealing experiments were conducted at pressure of 25 GPa and temperature of 1673-2073 K using a MA8 type high-pressure apparatus. The diffusion profiles were obtained by secondary ion mass spectrometry. The lattice and grain boundary diffusion coefficients (D 1 and D(gb)) were determined to be D 1 [m 2 /s] = 2.74 X 10 -10 exp(-336 [kJ/mol]/RT) and δD(gb) [m 3 /s] = 7.12 X 10 -17 exp(-311 [kJ/mol]/RT), respectively, where δ is the width of grain boundary, R is the gas constant and T is the absolute temperature. These diffusion coefficient play a key role for understanding the rheology of the lower mantle. (C) 2000 Elsevier Science B.V. All rights reserved.
  • M. Ito, H. Yurimoto, M. Morioka, H. Nagasawa
    Physics and Chemistry of Minerals 26 (6) 425 - 431 0342-1791|1432-2021 1999/07 [Refereed][Not invited]
     
    Diffusion coefficients of Co 2+ and Ni 2+ in synthetic single crystal forsterite along the c-axis were determined in the temperature ranges, 700-1200 °C and 800-1300 °C, respectively. The synthesized forsterite specimens were coated with thin evaporated films of CoO and NiO on the c-surface and annealed for diffusion experiments. The short penetration distance of diffusing ions in forsterite was measured by secondary ion mass spectrometry using the depth profile method. The observed diffusion coefficient values show good linear relationships in Arrhenius plots and the activation energy values obtained agree well with the previous values, although the diffusion coefficient values observed at the high temperature end of the experimental range deviate from the previous values. These results indicate that Co and Ni diffuse in olivine with a single mechanism within the temperature range observed, possibly with an extrinsic in nature as in the case of Mg tracer diffusion observed by Chakraborty et al. 1994 and of Fe-Mg interdiffusion by Chakraborty.
  • Seiji Maruyama, Hisayoshi Yurimoto, Shigeho Sueno
    Earth and Planetary Science Letters 169 (1/2) 165 - 171 0012-821X 1999/05 [Refereed][Not invited]
     
    Oxygen isotope compositions of individual mineral grains in two spinel-bearing chondrules have been determined by secondary ion mass spectrometry. O isotope ratios of spinel grains in a plagioclase-rich chondrule were extremely 16 O-rich (δ 18 O ~ δ 17 O ~ -35‰) indicating close relationship to spinels in Ca-Al-rich inclusions (CAIs), whereas O isotope ratios of a spinel grain in barred-olivine chondrule were less enriched in 16 O (δ 18 O ~ δ 17 O ~ -10‰). The degree of 16 O-excesses among minerals within each chondrule was parallel to the crystallization sequences. These measurements suggest that some CAI-spinel grains were incorporated into the chondrule precursors, and that the O isotopic variation among minerals may result in incomplete exchange of O isotopes between 16 O-rich chondrule melt and 16 O-poor ambient nebular gas. The mesostasis having an O-isotopic composition near the terrestrial fractionation line may have been somewhat affected by the aqueous alteration in the parent body.
  • H. Yurimoto
    Science 283 2102  00368075 1999/03 [Refereed][Not invited]
  • Hisayoshi Yurimoto, Hiroshi Nagasawa Motoo Ito
    Science 282 1874 - 1877 00368075 1998/12 [Refereed][Not invited]
     
    A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions (~5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.
  • H. Taura, H. Taura, H. Yurimoto, H. Yurimoto, K. Kurita, K. Kurita, S. Sueno
    Physics and Chemistry of Minerals 25 (7) 469 - 484 0342-1791|1432-2021 1998/08 [Refereed][Not invited]
     
    Partition coefficients between olivine and melt at upper mantle conditions, 3 to 14 GPa, have been determined for 27 trace elements (Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Rb, Sr, Y, Zr, Cs, Ba, La and Ce) using secondary-ion mass-spectrometry (SIMS) and electron-probe microanalysis (EPMA). The general pattern of olivine/melt partitioning on Onuma diagrams resembles those reported previously for natural systems. This agreement strongly supports the argument that partitioning is under structural control of olivine even at high pressure. The partition coefficients for mono- andtri-valent cations show significant pressure dependence, both becoming larger with pressure, and are strongly correlated with coupled substitution into cation sites in the olivine structure. The dominant type of trace element substitution for mono- and tri-valent cations into olivine changes gradually from (Si, Mg)↔(Al, Cr) at low pressure to (Si, Mg)↔(Al, Al) and Mg, Mg)↔(Na, Al) at high pressure. the change in substitution type results in an increase in partition coefficients of Al and Na with pressure. An inverse correlation between the partition coefficients for divalent cations and pressure has been observed, especially for Ni, Co and Fe. The order of decreasing rate of partition coefficients of Al and Na with pressure. An inverse correlation between the partition coefficients for divalent cations and pressure has been observed, especially for Ni, Co and Fe. The order of decreasing rate of partition coefficient with pressure correlates to strength of crystal field effect of the cation. The pressure dependence of olivine/melt partitioning can be attributed to the compression of cation polyhedra induced by pressure and the compensation of electrostatic valence by cation substitution.
  • Toru Inoue, Tetsuo Irifune, Hisayoshi Yurimoto, Isoji Miyagi
    Physics of the Earth and Planetary Interiors 107 (1/3) 221 - 231 0031-9201 1998/04 [Refereed][Not invited]
     
    The stability of K-amphibole has been studied at pressures 12.6-16.5 GPa, and at temperatures 940-1450°C. K-amphibole decomposes into an assemblage of clinoenstatite + diopside + an unknown phase (X) + stishovite + fluid at pressures above 16 GPa and temperatures below 1200°C. The phase boundary has a negative Clapeyron slope, and the high temperature assemblage is clinoenstatite + diopside + X + wadeite-type K 2 Si 4 O 9 + fluid at pressures 14-16 GPa. The X phase has a cation ratio of approximately K:Mg:Si = 1:2:2, and contains 1.7 ± 0.1 wt.% H 2 O as determined by SIMS measurements, leading to a formula of K 4 Mg 8 Si 8 O 25 (OH) 2 . The present results suggest that the decomposition of K-amphibole in the dragged hydrous peridotite layer at the base of the mantle wedge may produce certain amounts of H 2 O-rich fluid at 14-16 GPa (α450 km depth), while some of H 2 O is trapped in the new hydrous phase X and is further carried into deeper regions of the mantle. The aqueous fluid released by the decomposition of K-amphibole should react with β-phase to form hydrous β-phase in the mantle transition region. Thus, the dehydration of K-amphibole would not cause any volcanic activities in the back arc regions, in contrast to the dehydrations of amphibole, chlorite and phlogopite, which are presumably responsible for the first and the second volcanic chains. However, some of the volcanic activities such as in Muriah, Indonesia, may be related to the dehydration of K-amphibole in unusually hot regions about the subducting slab.
  • Natsue Abe, Shoji Arai, Hisayoshi Yurimoto
    Physics of the Earth and Planetary Interiors 107 (1/3) 233 - 248 0031-9201 1998/04 [Refereed][Not invited]
     
    Geochemical characteristics of clinopyroxene in peridotite xenoliths from three volcanos, Megata, On-yama and Kurose, in the Japan arcs are important for understanding igneous and metasomatic processes within the mantle wedge. The clinopyroxenes in peridotite xenoliths from the Japan arcs are clearly different from those in abyssal peridotites and the peridotite xenoliths from other tectonic settings, such as continental rifts and oceanic hotspots. Geochemical characteristics of the sub-arc clinopyroxenes are not apparently related either to degree of hydration or to degree of refractoriness, but are consistent from one sample to another. The REE patterns vary from LREE-depleted pattern to flat or slightly LREE-enriched patterns. Then their (Ce/Yb) N (subscript N = chondite-normalized) vary widely from 0.04 to 4.0. On the other hand the Ti/Zr ratio is rather constant in each sample, around 100. Clinopyroxenes in the Japan arcs peridotite xenoliths are intermediate for Ce and Sr contents, and (Ce/Yb) N and Ti£Zr ratios. Furthermore, the most fertile peridotites from Japan arcs are similar for the clinopyroxene chemistry to the most fertile abyssal peridotites. The peridotite xenoliths from Japan arcs had possibly evolved through different process from common source peridotite to abyssal peridotite. The Japan arc mantle peridotites had been polluted by the metasomatic agent with consistent chemical characteristics due to regional mantle wedge metasomatism.
  • Eiji Ohtani, Hiroki Mizobata, Yasuhiro Kudoh, Toshiro Nagase, Haruo Arashi, Hisayoshi Yurimoto, Isoji Miyagi
    Geophysical Research Letters 25 (7) 981 - 982 0094-8276|1944-8007 1998/04 [Refereed][Not invited]
     
    © Copyright 1998 by the American Geophysical Union. Phase G reported by Ohtani et al. [1997] and Kudoh et al. [1997a] is identical with the new phase D reported by Kuroda and Irifune [1998] and Yang et al. [1997] . However, there is ambiguity on existence of phase D defined by Liu [1987]. There are following possibilities on existence of Liu's phase D; (1) the product was a mixture of phase G and the other contaminant phases, (2) it realy exists stably in different pressure and temperature conditions from those studied by our works, or (3) the phase is a metastable phase formed due to a short run duration and/or no sealing of water in the diamond anvil cell. Therefore, it is not appropriate to use the name phase D for the dense hydrous magnesium silicate phase G reported by us [Ohtani et al., 1997] .
  • Kita Noriko T., Togashi Shigeko, Morishita Yuichi, Terashima Shigeru, Yurimoto Hisayoshi
    Antarctic meteorite research Antarctic meteorite research 11 103 - 121 13434284 1998/03 [Refereed][Not invited]
     
    We have developed a technique for in-situ Ni isotopic analysis using the ion microprobe, in order to detect ^<60>Ni excess from the decay of the short lived nuclide ^<60>Fe (half life=1.5Ma) in ureilite samples. The silicate minerals from MET-78008 ureilite with an old U-Pb age of 4.563±0.006 Ga were analyzed. The ^<56>Fe/^<58>Ni ratios of olivine and orthopyroxene are between 2700 and 5400. In spite of the high Fe/Ni ratios, we could not observe any detectable ^<60>Ni excess. From the mean value of olivine core data, we obtain an upper limit of the ^<60>Fe/^<56>Fe ratio at the time of ureilite formation of 1.8×10^<-7>. The time difference between CAI formation and ureilite formation was estimated to be more than 4 million years, which is consistent with the UPb data from the same meteorite. We concluded that the impact event for the disruption of the ureilite parent body happened more than 4 million years after CAI formation. However, a large uncertainty in the initial ^<60>Fe/^<56>Fe ratio is introduced by the possibility that the ^<60>Ni excess observed in CAIs is of nucleosynthetic origin. Our conclusion may change if the initial ^<60>Fe/^<56>Fe ratio of the solar system using CAI data is too high.
  • Eiji Ohtani, Eiji Ohtani, Hiroki Mizobata, Hiroki Mizobata, Yasuhiro Kudoh, Yasuhiro Kudoh, Toshiro Nagase, Toshiro Nagase, Haruo Arashi, Haruo Arashi, Hisayoshi Yurimoto, Hisayoshi Yurimoto, Isoji Miyagi, Isoji Miyagi
    Geophysical Research Letters 24 (9) 1047 - 1050 0094-8276|1944-8007 1997/12 [Refereed][Not invited]
     
    We synthesized a new hydrous silicate in the pressure range from 20 GPa to 24 GPa at 800-1300°C. This phase, named tentatively as phase G, has a hexagonal unit cell, a=4.790(3)Å and c=4.344(3)Å, and V=86.3(2)Å 3 and the atomic ratio Mg/Si=0.66±0.03. SIMS analysis revealed that it contains 14.5±2.0wt% water. Phase G has a chemical formula of Mg 1.14 Si 1.73 H 2.81 O 6 and a density of 3.37g/cm 3 . Phase G coexists with periclase and Mg-perovskite under the lower mantle conditions, and thus it can be a reservoir of water in cold slabs penetrating into the lower mantle. Copyright 1997 by the American Geophysical Union.
  • M. Kurosawa, H. Yurimoto, H. Yurimoto, S. Sueno
    Physics and Chemistry of Minerals 24 (6) 385 - 395 0342-1791|1432-2021 1997/08 [Refereed][Not invited]
     
    The concentrations of hydrogen and the other trace elements in olivines from mantle xenoliths have been determined by secondary ion mass spectrometry (SIMS) for clarifying the incorporation mechanism and the behavior of the hydrogen. The hydrogen contents in olivines from mantle xenoliths range from 10 to 60 ppm wt. H 2 O and the concentration range is consistent with the previous infrared (IR) spectroscopic data. IR spectra of the olivine crystals show no effects of the weathering or secondary alteration. The hydrogen is distributed homogeneously among olivine grains in each mantle xenolith. However, the hydrogen contents of the olivine crystals are less than those for the olivine phenocrysts crystallized from the host magma. Olivine inclusions in diamonds also show similar hydrogen contents to the xenolithic olivines. Thus the hydrogen content of xenolithic olivines does not attain equilibrium with water in the host magma during the transportation from the Earth's mantle to the surface, and is taken as a reflection of the hydrogen condition in the mantle. Correlations of hydrogen with trivalent cation contents in garnet peridotitic olivines indicate the incorporation of hydrogen into mantle olivines by a coupled substitution mechanism, with the hydrogen present in the form of hydroxyl in oxygen positions adjacent to the M site vacancies. The hydrogen content of xenolithic olivines increases with pressure but decreases with increasing temperature, suggesting importance of olivine as a water reservoir at low temperature regions such as in subducting slabs.
  • Eiji Ohtani, Hisayoshi Yurimoto, Shuji Seto
    Physics of the Earth and Planetary Interiors 100 (1/4) 97 - 114 0031-9201 1997/03 [Refereed][Not invited]
     
    We determined the partition coefficients of 19 elements between metallic liquid and silicate liquid at 20 GPa and 2500°C, and between metallic liquid and silicate perovskite at 27 GPa and 2200°C. Remarkable differences were observed in the partitioning behaviors of Si, P, W, Re, and Pb among the silicate liquid, perovskite, and magnesiowüstite coexisting with metallic liquid, reflecting incompatibility of the elements in the silicate or oxide phase. We could not observe any significant difference in the partitioning behaviors of V, Cr, Mn, Co, Ni, and Cu among the phases coexisting with metallic liquid. Comparison of the present partitioning data with those obtained previously at lower pressure and temperature suggests that the exchange partition coefficients, K met/sil , of Co, Ni, Mo, and W decrease, whereas those of V, Cr, and Mn increase and tend to approach unity with increasing pressure and temperature. We also made preliminary experiments to clarify the effect of sulfur on the partitioning behaviors. Sulfur lowers the exchange partition coefficients, K met/sil , of Mo and W between metallic liquid and silicate liquid significantly at 20 GPa and 2300°C. The mantle abundances of Co, Ni, Cu, Mo, and W calculated for the metal-silicate equilibrium model are lower than those of the real mantle, whereas P, K, and Mn are overabundant in the calculated mantle. The discrepancies in the abundances of Co and Ni could be explained by the chemical equilibrium at higher pressure and temperature. Large discrepancies in Mo and W between the calculated and real mantles could be accounted for by the effect of sulfur combined with the effects of pressure and temperature on the chemical equilibrium. The mantle abundances of P, K, and Cu could be accounted for by volatile loss in the nebula, perhaps before accretion of the Earth, combined with the chemical equilibrium at higher pressure and temperature. Thus the observed mantle abundances of P, K, Co, Ni, Cu, Mo, and W may be consistent with a model of sulfur-bearing metal-silicate equilibrium in lower-mantle conditions. © 1997 Elsevier Science B.V.
  • MIYAGI Isoji, YURIMOTO Hisayoshi, TAKAHASHI Eiichi
    GEOCHEMICAL JOURNAL Geochemical journal : journal of the Geochemical Society of Japan 31 (1) 57 - 61 00167002 1997/02 [Refereed][Not invited]
     
    Water solubilities in albite (Ab)-orthoclase (Or) join and JR-1 rhyolite melts at 1000°C and up to 2000 bars were determined by the “excess of water” method using an internally heated pressure vessel (IHPV) with rapid quenching and a secondary ion microprobe mass spectrometer (SIMS). We have found that secondary hydration of run product glass with coexisting aqueous fluid occurs during quenching. The hydration is significant in sodium-rich glass. The bulk analysis of such secondary hydrated run-products will cause overestimation of the water solubility, while the true water solubility can be obtained by micro-analysis on non-attacked portion of the glass. The apparent compositional dependence in the published water solubility data could be due to the secondary hydration of run product glass. Newly determined water solubility for the Ab-Or join and rhyolite melts is expressed as H2O (mol%) = 0.19 √PH2O (bar), at 1000°C.
  • I. Miyagi, H. Yurimoto, E. Takahashi
    Geochemical Journal 31 (1) 57 - 61 0016-7002|1880-5973 1997/01 [Refereed][Not invited]
     
    Water solubilities in albite (Ab)-orthoclase (Or) join and JR-1 rhyolite melts at 1000°C and up to 2000 bars were determined by the 'excess of water' method using an internally heated pressure vessel (IHPV) with rapid quenching and a secondary ion microprobe mass spectrometer (SIMS). We have found that secondary hydration of run product glass with coexisting aqueous fluid occurs during quenching. The hydration is significant in sodium-rich glass. The bulk analysis of such secondary hydrated run-products will cause overestimation of the water solubility, while the true water solubility can be obtained by micro-analysis on non-attacked portion of the glass. The apparent compositional dependence in the published water solubility data could be due to the secondary hydration of run product glass. Newly determined water solubility for the Ab-Or join and rhyolite melts is expressed as H 2 O (mol%) = 0.19√ PH 2 O (bar), at 1000°C.
  • Eiji Ohtani, Eiji Ohtani, Hisayoshi Yurimoto, Hisayoshi Yurimoto
    Geophysical Research Letters 23 1993 - 1996 00948276 1996/01 [Refereed][Not invited]
     
    We determined the partition coefficients of 20 elements between metallic liquid, magnsesiowustite, and silicate liquid at 20 GPa and 2500°C. The partition coefficients of V, Cr, Mn, Co, Ni, and Cu between metallic liquid and magnesiowustite are similar to those between metallic liquid and silicate liquid. The partitioning behavior of Si, P, W and Pb between metallic liquid and magnesiowustite show remarkable differences to that between metallic liquid and silicate liquid, reflecting incompatibility of these elements in magnesiowustite. Comparison of the present data with the previous ones implies that the metallic liquid-siicate liquid partition coefficients of Co, Ni, W, and Mo decrease whereas those of Cr, and Mn increase due to the combined effect of pressure and temperature, although some other factors such as the liquid composition might play some roles on a large difference in D for Mo and W. The core and mantle concentrations for Co and Ni estimated by Allegre et al. [1995] are consistent with the metal-silicate equilibrium at lower mantle conditions, although other models such as inhomogeneous accretion are also able to explain the core-mantle concentrations. Copyright 1996 by the American Geophysical Union.
  • Shoji Arai, Hisayoshi Yurimoto
    Island Arc 4 104 - 111 10384871 1995/01 [Refereed][Not invited]
     
    Abstract The sub‐arc mantle condition possibly favors the formation of podiform chromitites. The Cr/(Cr + Al) atomic ratio (= Cr#) of their chromian spinel frequently is higher than 0.7, which is comparable with the range for arc‐related primitive magmas. This almost excludes the possibility of their sub‐oceanic origin, because both oceanic peridotites and MORB have chromian spinel with the Cr# < 0.6. Precipitation of chromitite and associated dunite enhances a relative depletion of high‐field strength elements (HFSE) to large‐ion lithophile elements (LILE), one of chemical characteristics of arc magmas, for the involved magma. This cannot alter completely, however, the MORB to the arc‐type magma, especially for Ti and Zr. The presence of chromitite xenoliths, similar both in texture and in chemistry to podiform chromitites of some ophiolitic complexes, in some Cenozoic alkali basalts from the southwest Japan arc indicates directly that the upper mantle beneath the Japan arcs has chromitites. Copyright © 1995, Wiley Blackwell. All rights reserved
  • Toshiaki Tsunogae, Hisayoshi Yurimoto
    Geochemical Journal 29 197 - 205 00167002 1995/01 [Refereed][Not invited]
     
    Single zircon U-Pb chronology was applied to help understanding the evolution of the Limpopo Belt in southern Africa. High mass resolution = 6000) obtained by a CAMECA IMS-3F ion microprobe was sufficient to determine Pb/U ratios of zircon crystals without any significant mass interferences. U-Pb ages of euhedral zircons from the belt cluster at around 3.2 Ga for the Central Zone and 2.8 Ga for the Northern Marginal Zone. The difference in age between the two zones can be explained by difference in protolith age. Timing of metamorphism was identified for the Northern Marginal Zone as 2 to 1.7 Ga which is younger than previously reported metamorphic ages of the Limpopo Belt. © 1995, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.
  • Hiroshi Nagasawa, Hisayoshi Yurimoto, Masana Morioka
    GEOCHEMICAL JOURNAL 29 (2) 155 - 161 0016-7002|1880-5973 1995/01 [Refereed][Not invited]
     
    Hf-Zr interdiffusivity in zircon has been determined on hafnon-zircon double-layered crystals using back-scattered electron image contrast in a scanning electron microscope. The observed Hf-Zr interdiffusion coefficient at 1600°C and 1500°C in the direction perpendicular to the c-axis is 2 x 10 –15 and 3 x 10 –16 cm 2 /sec, respectively. The value observed at 1600°C perpendicular to the c-axis is about an order of magnitude higher compared with the value of ~2 x 10 -16 cm 2 /sec along the c-axis. These observed low diffusivity values suggest that diffusivities of Th and U in zircon are expected to be similarly low. © 1995, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.
  • Toru Inoue, Hisayoshi Yurimoto, Yasuhiro Kudoh
    Geophysical Research Letters 22 117 - 120 00948276 1995/01 [Refereed][Not invited]
     
    The water content in modified spinel, synthesized at 15.5 GPa under hydrous conditions, has been measured by means of secondary ion mass spectrometry (SIMSrpar;. We found that the modified spinel crystals contain up to 3.1±0.4 wt % H 2 O, which is consistent with the amounts estimated from the deficits in the oxide totals of the microprobe analysis. X‐ray diffraction analyses for a single crystal showed that the sample containing 2.5±0.3 wt % H 2 O is of the modified spinel structure with the lattice parameters a=5.663(1), b=11.546(2), c=8.247(4)Å and V=539.2(5)ų. The present results suggest that a considerable amount of H 2 O may exist as hydrous modified spinel in the mantle transition zone, which could have important implications for the constitution and dynamics of the mantle. Copyright 1995 by the American Geophysical Union.
  • Hisayoshi Yurimoto, Hiroshi Nagasawa, Yoshiharu Mori, Osamu Matsubaya
    Earth and Planetary Science Letters 128 (1/2) 47 - 53 0012-821X 1994/01 [Refereed][Not invited]
     
    Isotope ratios of oxygen have been measured on a fassaite crystal and the surrounding area of a coarse-grained CAI from the Allende meteorite using secondary ion mass spectrometry. Values of δ 18 O SMOW for fassaite, spinel, anorthite grains and alteration products are -27 ± 5, -38 ± 2, +5 ± 6, and +4‰, respectively, which are consistent with the results obtained on mineral separates. The O isotopic distributions are homogeneous either within individual single crystals of fassaite and anorthite or among the spinel grains within the analytical error. No gradual variation in O isotopic composition was detected even at the boundary between different phases or at cracks inside a phase with a spatial resolution of 10 μm. These observations strongly suggest that the partial exchange of O isotopes in the minerals in the CAI with the surrounding gas through diffusion is an unlikely origin for the observed inter-mineral heterogeneity of O isotopes in the Allende CAIs. © 1994.
  • S. Arai, H. Yurimoto
    Economic Geology 89 1279 - 1288 03610128 1994/01 [Refereed][Not invited]
     
    Petrological and geochemical data for chromian spinel from the Tari-Misaka ultramafic complex, southwest Japan, are discussed. In this complex, the spinels form a chromitite pod coated by a dunite envelope and are collectively enclosed by clinopyroxene-bearing harzburgite. The chemistry of the chromian spinel and the mode of occurrence of the dunite-chromitite association are consistent with an origin by interaction of an exotic melt with wall-rock harzburgite. The dunite may be of replacive origin. Podiform chromitite is most commonly formed in the mantle beneath island arcs. The spread in Cr ratios of spinel in podiform chromitites is almost comparable with that of spinel in primitive arc-related magmas. -from Authors
  • Hisayoshi Yurimoto, Yoshiharu Mori, Hironori Yamamoto
    Review of Scientific Instruments 64 (5) 1146 - 1149 1089-7623|0034-6748 1993/12 [Refereed][Not invited]
     
    A small, compact negative-ion source based on plasma sputtering has been developed for secondary-ion mass spectrometry (SIMS). It can make precise measurements of the oxygen isotope ratios in minerals. From a copper sputter target, a high-density 63 Cu - ion beam of 3 mA cm -2 has been obtained as the primary-ion beam with a size of 100 μm in diameter. The mass distribution of the ion beam is 99% Cu - and 1% Cu - 2 ions; other ionic species comprise less than 0.1%. A typical beam stability for 10 min has been achieved at 0.4% (σ). These performances of the negative-ion source are useful to perform in situ analyses of insulator materials in SIMS. As an application, the high-mass resolution spectra for three isotopes of oxygen secondary ions from an insulator sample bombarded by the 63 Cu - ion beam was studied.
  • Koike Osamu, Yurimoto Hisayoshi, Nagasawa Hiroshi, Sueno Shigeho
    Proceedings of the NIPR Symposium on Antarctic Meteorites Proceedings of the NIPR Symposium on Antarctic Meteorites 6 357 - 363 09145621 1993/05 [Refereed][Not invited]
     
    Magnesium isotopes in individual mineral grains of a Ca-Al rich inclusion from the Allende meteorite have been measured by secondary ion mass spectrometry. An electrostatic peak switching system was used to make a precise isotopic measurement in high mass resolution mode (M/⊿M=∿4000). The inclusion shows excess of ^<26>Mg correlated with the ^<27>Al/^<24>Mg ratio. The results suggest that live ^<26>Al decayed in the inclusion which formed simultaneously in the solar nebula. The relative abundance of ^<26>Al(^<26>Al/^<27>Al=3.12×10^<-5>) is close to the "canonical" value (^<26>Al/^<27>Al=∿5×10^<-5>) for coarse-grained CAIs.
  • M. Kurosawa, H. Yurimoto, S. Sueno
    Annual Report - University of Tsukuba, Institute of Geoscience 18 83 - 88 1992/12 [Refereed][Not invited]
     
    This study shows examples of the SIMS quantitative analysis of trace H, Ni and Ca in mantle olivine crystals. Secondary ion intensities of the elements were correlated to absolute concentration by three kinds of standard materials: 1) fused glass rock standards, 2) natural olivine standards, and 3) ion implanted standards. The concentration gave good agreement with the result determined by EPMA (Ca, Ni) and the previous study (H). -from Authors
  • Isao Sakaguchi, Hisayoshi Yurimoto, Sigeho Sueno
    Materials Science and Engineering B 13 (3) 1 - 4 0921-5107 1992/04 [Refereed][Not invited]
     
    Tracer diffusion of Li + , Na + , Si 4+ and P 5+ in single-crystal MgO has been performed. The lattice and dislocation diffusion coefficients were determined from diffusion penetration measured by SIMS. Temperature dependence of the lattice and dislocation diffusion among these ions was argued to connect with the property of ions. © 1992.
  • Hisayoshi Yurimoto, Eiji Ohtani
    Geophysical Research Letters 19 17 - 20 00948276 1992/01 [Refereed][Not invited]
     
    The secondary ion mass spectrometry (SIMS) was applied to measure the trace element abundances in majorite and the ultramafic liquid equilibrating at high pressure and temperature for the first time, and was proved to be useful for the high pressure experimental petrology. The analysis by SIMS was made to determine the abundance of 15 lithophile elements (Li, Be, B, Sc, Ti, V, Cr, Mn, Y, Zr, La, Sm, Gd, Yb, and Hf), one siderophile (Co), and two chalcophile elements (Cu, Zn). The electron microprobe (EPMA) analysis was also made to obtain the major element abundance. Some lithophile elements (Al, Be, and V) are enriched in majorite, whereas the lithophile elements (Li, B, Na, K, Ca, Ti, Zr, Y, La, Sm, Gd, and Hf), and siderophile and chalcophile elements (Co, Cu, Zn) are favored in the liquid. These results give important constraint for the genesis of komatiites and chemical heterogeneity in the Archean mantle. Copyright 1992 by the American Geophysical Union.
  • Isao Sakaguchi, Hisayoshi Yurimoto, Shigeho Sueno
    Journal of the American Ceramic Society 75 (3) 712 - 715 1551-2916|0002-7820 1992/01 [Refereed][Not invited]
     
    The lattice and dislocation diffusion coefficients for Ca 2+ in single‐crystal MgO have been determined in the temperature range 1743 to 1293 K from the diffusion penetration determined using secondary ion mass spectrometry. The dislocation diffusion coefficients were 4 to 5 orders of magnitude larger than the lattice diffusion coefficients in the same temperature range. The activation energy of Ca 2+ lattice diffusion was comparable to that of ionic conductivity. The diffusion mechanism of Ca 2+ is related to Mg vacancies. Copyright © 1992, Wiley Blackwell. All rights reserved
  • Isao Sakaguchi, Hisayoshi Yurimoto, Shigeho Sueno
    Journal of the American Ceramic Society 75 (12) 3477 - 3480 1551-2916|0002-7820 1992/01 [Refereed][Not invited]
     
    Diffusion profiles of Sr in single‐crystal MgO at 1473 to 1843 K have been determined by a depth‐profiling technique using secondary ion mass spectrometry. The diffusion experiments were performed using a focusing infrared furnace. The temperature dependences of lattice and dislocation diffusion are D 1 = 2.6 × 10 −11 exp(–268.2/RT [kJ/mol])[m 2 .s ‐1 ], D d = 1.7 × 10 4 exp(–562.3/RT), respectively. The present lattice diffusion coefficients are three orders of magnitude smaller than those previously reported. Si diffused with Sr in MgO over 1583 K, and the diffusion coefficients of Si were also determined. The results of Si diffusion were equivalent to those of our previous study. Copyright © 1992, Wiley Blackwell. All rights reserved
  • Isao Sakaguchi, Hisayoshi Yurimoto, Sigeho Sueno
    Solid State Communications 84 (9) 889 - 893 1879-2766|0038-1098 1992/01 [Refereed][Not invited]
     
    Self-diffusion of 26 Mg in single crystal MgO has been investigated at low temperature side (1573-973 K). The lattice and dislocation diffusion coefficients were determined from diffusion penetration which was measured by SIMS. The dislocation pipe diffusion was 4-5 orders faster than the lattice diffusion at the same temperature. © 1992.
  • Hisayoshi YURIMOTO, Hisayoshi YURIMOTO, Isao SAKAGUCHI, Norimasa NISHIDA, Shigeho SUENO
    Geostandards Newsletter 15 155 - 159 01505505 1991/01 [Refereed][Not invited]
     
    Trace level determination of nickel in silicate rock samples has been achieved using secondary ion mass spectrometry (SIMS) with kinetic energy filtering. Standard rock references, issued by the Geological Survey of Japan, were fused into glass and used as standards for the SIMS analysis. Due to interferences from the glass matrix, the secondary ion of mass 60 was only useful for Ni, although the secondary ion was interfered mainly by CaO+. The contributions of these molecular ions were deconvolved by a least squares regression. Good linear correlation between results after the deconvolution and the Ni concentration in the glass standards was obtained. The uncertainties of the SIMS analysis depend strongly on the degree of contribution of CaO+ molecular ion. Such a method of SIMS analysis is especially useful to study the detailed behavior of Ni on a micro‐scale in Ca‐poor materials. Copyright © 1991, Wiley Blackwell. All rights reserved
  • C. K. Shearer, J. J. Papike, S. B. Simon, N. Shimizu, H. Yurimoto, S. Sueno
    Geochimica et Cosmochimica Acta 54 (3) 851 - 867 0016-7037 1990/01 [Refereed][Not invited]
     
    The major element geochemistry of picritic lunar glass beads indicates that they represent primary basaltic liquid compositions and, as such, provide unique information concerning the origin of mare basalts and characteristics of the lunar interior. This study used ion microprobe techniques for trace element analysis of individual glass beads representing seven compositionally distinct types of picritic glass beads from the Apollo 14 site [high-Ti glasses (17-11% TiO 2 ): Red/Black, Orange; intermediate-Ti glasses (5-4% TiO 2 ): Yellow; low-Ti glasses (2.8% TiO 2 ): LAP (low alkali, picritic; Papike et al., 1989); very low-Ti glasses ( < 1% TiO 2 ): Green A, VLT, Green B]. The Green B, Green A, VLT, and LAP glasses are typically LREE enriched. The total REE abundance of Green A, VLT, and LAP overlap (Ce = 30 to 80 × chondrite) whereas the REE abundances of the more MgO-rich Green B are substantially lower (Ce = 8 to 18 × chondrite). The trace element signature [REE patterns and abundances, ( Ba Sr) > 1] of these glasses are different from low-Ti mare basalts at other sites but are similar to crystalline basalts at the Apollo 14 site. The intermediate to high-Ti picritic glasses exhibit a flat to slightly positive LREE slope and a negative HREE slope. The Orange glass has a higher total REE abundance and a slightly larger negative Eu anomaly than the Red/Black and Yellow glasses. Relative to the Apollo 17 high-Ti glasses, Apollo 14 high-Ti glasses are enriched in REE, LREE/HREE, Y, V, Zr, Sr, Ba, and Ba Sr and are similar in alkali elements (Li, Rb), Co, and Sc. Trace element modeling, within the context of liquid lines of desce nt and major element characteristics, indicates that the picritic glass beads at the A-14 site are not related by low pressure fractional crystallization to each other or to crystalline basalts at the Apollo 14 or other landing sites. A possible exception is the relationship between LAP and basalts of the high-Al basalt suite. The wide range of primary magma compositions and the lack of petrogenetic linkage (via crystal fractionation) to crystalline basalts indicates that either a wide compositional range of evolved mare basalts has not yet been sampled or a unique mechanism is selectively tapping these picritic magmas directly from their mantle source region. The wide range of major and trace element characteristics of the volcanic glass beads is consistent with derivation from mineralogically distinct sources which consist of varying proportions of olivine + orthopyroxene ± clinopyroxene ± ilmenite ± plagioclase ± KREEP component. The evolved KREEP component may have been incorporated into these primary picritic magmas by either assimilation-fractional crystallization-type processes (AFC) or by hybridization of the mantle source. The former appears less likely due to the general systematic increase in incompatible elements relative to Ti concentration and the apparent lack of crystallization that is required in AFC-type models. The hybridization processes may be the result of "sinker" mechanisms as proposed by Ringwood and Kesson (1976), a manifestation of original mantle inhomogeneities, or a magma ocean stirred by large impacts. © 1990.
  • Hisayoshi Yurimoto, E. F. Duke, J. J. Papike, C. K. Shearer
    Geochimica et Cosmochimica Acta 54 (7) 2141 - 2145 0016-7037 1990/01 [Refereed][Not invited]
     
    All 14 stable rare earth elements (REEs) in biotite-muscovite granite and tourmaline-rich granite of the Harney Peak Granite, Black Hills, South Dakota, USA, have been analyzed using inductively coupled plasma mass spectrometry. Chrondrite-normalized REE patterns of the tourmaline-rich granites are discontinuous between Nd and Sm. The discontinuity was modeled successfully by the fractional crystallization of monazite from a biotite-muscovite granite initial composition. This explanation may also apply to the development of such discontinuous patterns in other highly evolved rocks. © 1990.
  • Hisayoshi Yurimoto, Masana Morioka, Hlroshi Nagasawa
    Geochimica et Cosmochimica Acta 53 (9) 2387 - 2394 0016-7037 1989/01 [Refereed][Not invited]
     
    Diffusion profiles of 18 O tracer in single crystals of gehlenite and åkermanite following annealing at 1000°-1300°C have been determined by a depth-profiling technique using secondary ion mass spectrometry. From the 18 O depth profiling the lattice diffusion coefficients for oxygen along the crystallographic axes in gehlenite and åkermanite, D 1 geh //c, D 1 · ak //a and D 1 · ak //c, respectively, are given by: D 1 geh //c = 4.36 × 10 -12 exp(- 186 ± 16 [kJ mol -1 ] RT) [m 2 sec -1 ]D 1 a ̇k //a = 6.96 × 10 -6 exp(- 300 ± 37 [kJ mol -1 ] RT) [m 2 sec -1 ]D 1 a ̇k //c = 9.41 × 10 -10 exp(- 215 ± 51 [kJ mol -1 ] RT) [m 2 sec -1 ] Present results are two to four orders of magnitude lower than those previously reported for melilite solid solutions (HAYASHl and Muehlenbachs, 1986). These high diffusion rates in melilite solid solutions and the heterogeneous distribution of O isotopes in the Allende Ca, Al-rich inclusions (CAIs) have been examined considering the contribution of fast diffusion along dislocations and possible changes in diffusion rate with gehlenite-åkermanite ratios in melilite. For this purpose, diffusion coefficients of O along dislocations were calculated by analyzing "tailing" of the O-diffusion profiles. From the effective diffusion rate in melilite solid solution obtained by lattice and dislocation diffusion rates, it is unlikely that the O-isotope differences in the Allende CAI minerals are the result of diffusion processes during a postcrystallization thermal event. © 1989.
  • Hisayoshi Yurimoto, Masanori Kurosawa, Shigeho Sueno
    Geochimica et Cosmochimica Acta 53 (3) 751 - 755 0016-7037 1989/01 [Refereed][Not invited]
     
    Microanalysis of hydrogen in quartz crystals and quartz glasses has been developed by secondary ion mass spectrometry (SIMS). The secondary ion intensities of hydrogen are proportional to the hydrogen contents determined by infrared (IR) absorption over the range of 5 to 3000 ppma H/Si. The correlation between SIMS and IR results indicates that secondary ion yields of hydrogen are independent of crystal structure. This SIMS method could reveal correlations between hydrogen distribution and hydrolytic weakening at the microscopic level. © 1989.
  • Hisayoshi Yurimoto, Aya Yamashita, Shigeho Sueno, Norimasa Nishida
    Geochemical Journal 23 (5) 215 - 236 0016-7002|1880-5973 1989/01 [Refereed][Not invited]
     
    Glasses prepared from JA-1, JA-2, JA-3, JB-1, JB-1a, JB-2, JB-3,JGb-1, JR-1 and JR-2 rock standards were found to be homogeneous standards appropriate for SIMS micro-analysis. Simultaneous micro-analysis of major, minor and trace elements in ng samples is made possible by use of the glass standards. This method uses energy filtering and, for REE’s and Hf, the contribution of simple oxide ions were corrected. Using specific SIMS operating conditions, linear calibration curves have been established for 38 elements (Li, Be, B, Na, Mg, Al, P. K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Rb, Sr, Y, Zr, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Hf). The typical accuracy of the analyses are within 10% of the recommended values for the elements over 1 ppm. Complications were encountered as described below: (1) Secondary ion yield for Na was enhanced in JF-, JG- and JR-series glasses which have relatively higher Si concentrations than the other standard glasses, whereas the yield of REE was reduced on JR-series glasses. The results demonstrate that systematic errors occur among silicates with different Si abundances for these elements. (2) Energy filtering was ineffective in removing interferences on the P and Sc peaks. The detection limits of these elements are controlled by the background level of the masses. Despite these problems, the empirical relationships obtained in this study are still useful for the application of quantitative SIMS to geological samples. © 1989, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.
  • Mutsukazu Kamo, Hisayoshi Yurimoto, Yoichiro Sato, Nobuo Setaka
    Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films 6 (3 Pt.2) 1818 - 1819 0734-2101|1520-8559 1988/01 [Refereed][Not invited]
  • Matsukazu Kamo, Hisayoshi Yurimoto, Yoichiro Sato
    Applied Surface Science 33/34 553 - 560 0169-4332 1988/01 [Refereed][Not invited]
     
    The growth features of diamond from the gas phase have been studied using (111), (110) and (100) planes of diamond as substrates. The deposition layers were studied by reflection electron diffraction, Raman spectroscopy, scanning electron microscopy, secondary ion mass spectroscopy and absorption spectroscopy. Epitaxial growth on these planes was observed for the various crystallographic orientations. The growth rate decreases in the order (111) ≅ (110) > (100). Epitaxially grown layers on the (111) and (110) planes were obtained in the temperature range from 820 to 950°C. On the other hand, the layer on the (100) plane was only observed at 820°C. The investigation of the properties of the deposited layers suggests that the layers can be contaminated by elements present in the substrate holder which may arise from the impact of plasma particles, and that the grown diamond belongs to Type IIa diamond, the purest form of natural diamond. © 1988.
  • Hisayoshi Yurimoto, Shigeho Sueno
    Geochemical Journal 21 85 - 104 00167002 1987/01 [Refereed][Not invited]
     
    Partition coefficients for — 1, -2, —3, +1, +2, +3, +4 and +5 valent ions between the groundmass of boninite and coexisting phenocrysts, bronizite, protoenstatite, augite and chrome spinel, from Bonin Island, Japan have been determined by secondary ion mass spectrometry (SIMS). The SIMS method could reveal the equilibria between the phenocrysts and the groundmass glass. The method has been useful in determining the partition coefficient for trace elements of the rock. The present anion and cation partitioning strongly supports the “crystal structure control” mechanism (Onuma et al., 1968; Yurimoto and Sueno, 1984a). Each of the crystallographic site gives rise to a parabola-shaped peak on partition coefficient vs. ionic radius diagram. On the diagrams for three kinds of pyroxene, sharpness of their peaks is consistent with geometrical flexibility of the corresponding coordination polyhedra, and relative height between the partition curves for homovalent ions is controlled by electrostatic charge balancing their crystallographic sites. © 1987, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.
  • Hisayoshi Yurimoto, Shigeho Sueno
    GEOCHEMICAL JOURNAL 18 85 - 94 00167002 1984/01 [Refereed][Not invited]
     
    Partition coefficients for —1, -2, -3, +1, +2, +3, +4 and +5 valent ions between the groundmass of tholeiite basalt and coexisting olivine and plagioclase phenocrysts from the Mid-Atlantic Ridge have been determined by secondary ion mass spectrometry. The present cation partitioning strongly supports the “crystal structure control” mechanism, The partition coefficient for an anion is also under control of the crystal structure, so that each of the cation and anion positions in the crystal structure gives rise to a parabola-shaped peak on the partition coefficient vs. ionic radius diagram. © 1984, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

MISC

  • 安部正真, 安部正真, 圦本尚義, 圦本尚義  日本惑星科学会誌 遊・星・人  27-  (2)  92‐95  2018/06   [Not refereed] [Not invited]
  • 圦本 尚義  地球化学 = Geochemistry  51-  (2)  49  -59  2017   [Not refereed] [Not invited]
  • 殿谷梓, 馬上謙一, OLINGER Chad T, JUREWICZ Amy J G, 坂口勲, 鈴木拓, BURNETT Donald S, 糸瀬悟, 石原盛男, 内野喜一郎, 圦本尚義, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2017-  ROMBUNNO.PPS10‐04 (WEB ONLY)  2017   [Not refereed] [Not invited]
  • 松本徹, 長谷川直, 圦本尚義, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2017-  ROMBUNNO.PPS10‐07 (WEB ONLY)  2017   [Not refereed] [Not invited]
  • 川崎教行, SIMON Steven B, GROSSMAN Lawrence, 坂本直哉, 圦本尚義, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2017-  ROMBUNNO.PPS10‐29 (WEB ONLY)  2017   [Not refereed] [Not invited]
  • 圦本尚義  地球化学  51-  (2)  49‐59(J‐STAGE)  -59  2017   [Not refereed] [Not invited]  

    Oxygen is the third most abundant element in the Universe and the most abundant element of the terrestrial planets. The presence of oxygen in gaseous, ice and dust phases makes oxygen isotopes important tracers of various fractionation processes to form a protoplanetary accretion disk, which are essential for understanding the evolution of building blocks for planet formation. Photodissociation of CO isotopologues in cold interstellar environments forms H2O ice with depletion of 16O component relative to the interstellar CO, but with heritage 17O/18O ratio from the interstellar CO. Dynamic evolution of protoplanetary disk generates H2O enrichments inside snowline of the disk to change from 16O-rich to 16O-poor gaseous environments. Thermodynamics during heating processes reset oxygen isotopic compositions of dust in the disk to the gaseous oxygen isotope values. Therefore, building blocks of planet show oxygen isotope variations with variable 16O component, but with similar 17O/18O ratio each other. Oxygen isotopic compositions of outer planets would be 16O-poor in order of increasing distance from the Sun if outer planet formation started from icy planetesimal accretion.

  • 岡田達明, 癸生川陽子, 伊藤元雄, 青木順, 河井洋輔, 寺田健太郎, 豊田岐聡, 岡本千里, 中村良介, 矢野創, 松岡彩子, 横田勝一郎, 岩田隆浩, 松本純, 森治, 圦本尚義, BIBRING Jean‐Pierre, COTTIN Herve, PALOMBA Ernesto, HELBERT Joern, ULAMEC Stephan, JAUMANN Ralf  宇宙科学技術連合講演会講演集(CD-ROM)  61st-  ROMBUNNO.2G19  2017   [Not refereed] [Not invited]
  • 矢田達, 安部正真, 岡田達明, 吉武美和, 坂本佳奈子, 松本徹, 中埜夕希, 川崎教行, 西村征洋, 熊谷和也, 松井重雄, 圦本尚義, 圦本尚義, 藤本正樹, 藤本正樹  日本地球惑星科学連合大会予稿集(Web)  2017-  ROMBUNNO.PPS02‐P27 (WEB ONLY)  2017   [Not refereed] [Not invited]
  • Masuda Harue, Yurimoto Hisayoshi  Chikyukagaku  51-  (4)  i  -i  2017   [Not refereed] [Not invited]
  • 久我ゆかり, WU Ting‐Di, WU Ting‐Di, GUERQUIN‐KERN Jean‐Luc, GUERQUIN‐KERN Jean‐Luc, 永田康祐, 坂本直哉, 圦本尚義, 勝山千恵  日本微生物生態学会大会(Web)  2017-  (0)  ROMBUNNO.O‐131 (WEB ONLY)  2017   [Not refereed] [Not invited]
  • 久我ゆかり, 山田博之, 田代智子, 勝山千恵, 中村仁, 坂本直哉, 圦本尚義  日本土壌微生物学会講演要旨集  2016-  9  2016/06   [Not refereed] [Not invited]
  • 浅井恵, 兼平裕也, 伊藤哲平, 屋代充, 園生智弘, 小林幸雄, 居城邦治, 圦本尚義, 重松隆, 木村(須田)廣美  日本骨形態計測学会雑誌  26-  (1)  S160  -S160  2016/06   [Not refereed] [Not invited]
  • 矢田達, 安部正真, 岡田達明, 圦本尚義, 上椙真之, 唐牛譲, 中藤亜衣子, 橋口未奈子, 松本徹, 西村征洋, 熊谷和也, 松井重雄, 藤本正樹  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.PCG10‐03 (WEB ONLY)  2016   [Not refereed] [Not invited]
  • 川崎教行, 伊藤正一, 坂本直哉, 圦本尚義, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.PPS12‐04 (WEB ONLY)  2016   [Not refereed] [Not invited]
  • 吉成耕一, 馬上謙一, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.SGL38‐P05 (WEB ONLY)  2016   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  63-  (0)  2016   [Not refereed] [Not invited]  

    Are spectrometers in your laboratory useful to analyze your geochemical problems? Are state-of-the-art spectrometers in the world useful to analyze your geochemical problems? Do you need to invent novel spectrometers to analyze your geochemical problems? I would like to discuss with peoples who answer YES for the last question. Why do we want to invent novel analyzers beyond state-of-the-art spectrometer? Because new geochemical problems, which are difficult to solve by use of state-of-the-art spectrometers, are discovered by yours. Development of novel spectrometers begins collaboration between new types of physics and chemistry, and advance towards discovery of new spectrometer. I would like to discuss the case of isotope microscope, as an example that discovery on geochemistry has been made by an invention of new spectrometer.

  • 殿谷梓, 馬上謙一, 糸瀬悟, 石原盛男, 内野喜一郎, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.MTT28‐P03 (WEB ONLY)  2016   [Not refereed] [Not invited]
  • 橋口未奈子, 小林幸雄, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.PPS12‐15 (WEB ONLY)  2016   [Not refereed] [Not invited]
  • 圦本尚義, 圦本尚義  日本地球化学会年会講演要旨集  63rd-  (0)  148  2016   [Not refereed] [Not invited]  

    The Astromaterials Science Research group of JAXA has been organized in 2015 as successor to the extraterrestrial curation facility. New mission of the group is research oriented in addition to routine operational services to scientific communities. As a result, it is necessary to enhance strong interactive relationship with material scientists of industry-government-academia research communities in the world. In this presentation, I introduce present status of the group with the history and we would like to discuss strategy for the enhancement towards new generation sample return missions of Hayabusa2, OSIRIS-Rex, and MMX.

  • 井上徹, 柿澤翔, CAI Nao, 藤野清志, 栗林貴弘, 長瀬敏郎, GREAUX Steeve, 肥後祐司, 阪本直哉, 圦本尚義, 服部高典, 佐野亜沙美  高圧討論会講演要旨集  56th-  45  2015/10   [Not refereed] [Not invited]
  • 坪井香奈子, 長谷川智香, 本郷裕美, 圦本尚義, 小林幸雄  Clin Calcium  25-  (10)  1505-1511,1428  -1511  2015/09   [Not refereed] [Not invited]  
    骨細胞の細胞突起は三次元的複雑な分布をし、骨細胞・骨細管系と呼ばれる細胞性ネットワークを形成している。今回我々は構造化照明顕微鏡法(SIM)や集束イオンビーム走査電子顕微鏡(FIB-SEM)を用いて骨細胞・骨細管系の三次元微細構造を観察し、細胞突起の走行の様子を詳細に観察した。また、同位体顕微鏡システムを用いて骨基質へのカルシウム沈着やミノドロン酸の骨組織内部での局在を検索したところ、新たな知見を得ることができた。さまざまな顕微鏡をその試料に応じて適切に選択することで、今まで明らかとならなかった種々の事象を解明することができると思われる。(著者抄録)
  • 黒田みなみ, 橘省吾, 奥村聡, 中村美千彦, 坂本直哉, 圦本尚義  日本鉱物科学会年会講演要旨集  2015-  5  2015/09   [Not refereed] [Not invited]
  • 柿澤翔, 井上徹, 栗林貴弘, 圦本尚義  日本鉱物科学会年会講演要旨集  2015-  109  2015/09   [Not refereed] [Not invited]
  • 殿谷梓, 馬上謙一, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2015-  ROMBUNNO.MTT44‐02 (WEB ONLY)  2015   [Not refereed] [Not invited]
  • 川崎教行, 加藤千図, 伊藤正一, 若木重行, 伊藤元雄, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2015-  ROMBUNNO.PPS22‐13 (WEB ONLY)  2015   [Not refereed] [Not invited]
  • 山本淳博, 川崎教行, 坂本直哉, 圦本尚義  日本地球惑星科学連合大会予稿集(Web)  2015-  ROMBUNNO.PPS22‐12 (WEB ONLY)  2015   [Not refereed] [Not invited]
  • KAKIZAWA SHO, INOUE TOORU, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  55th-  127  2014/11   [Not refereed] [Not invited]
  • INOUE TOORU, YABUKI TOMOMI, KAKIZAWA SHO, FUJINO KIYOSHI, YURIMOTO HISAYOSHI, KURIBAYASHI TAKAHIRO, NAGASE TOSHIRO  高圧討論会講演要旨集  55th-  10  2014/11   [Not refereed] [Not invited]
  • YOSHINO TAKASHI, SAKURAI MOE, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  55th-  6  2014/11   [Not refereed] [Not invited]
  • INOUE TOORU, YABUKI TOMOMI, KAKIZAWA SHO, FUJINO KIYOSHI, YURIMOTO HISAYOSHI, KURIBAYASHI TAKAHIRO, NAGASE TOSHIRO  日本鉱物科学会年会講演要旨集  2014-  114  2014/09   [Not refereed] [Not invited]
  • KUGA YUKARI, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI  日本土壌肥料学会講演要旨集  60-  36  2014/09   [Not refereed] [Not invited]
  • KIMURA(SUDA) HIROMI, ITO TEPPEI, KANAZAWA KYOSUKE, KOBAYASHI SACHIO, IJIRO KUNIHARU, YURIMOTO HISAYOSHI  日本腎臓学会誌  56-  (3)  327  -327  2014/05   [Not refereed] [Not invited]
  • SASAKI SOKI, HONGO YUMI, KOBAYASHI SACHIO, ODA KIMIMITSU, YURIMOTO HISAYOSHI, AMIZUKA NORIO  日本骨形態計測学会雑誌  24-  (2)  S112  -S112  2014/05   [Not refereed] [Not invited]
  • OGASAWARA KIMI, SAKAMOTO NAOYA, ITO TOSHIAKI, NAITO SATOSHI, TAKANO JUMPEI, YURIMOTO HISAYOSHI  日本顕微鏡学会関東支部講演会予稿集  38th-  41  2014/03   [Not refereed] [Not invited]
  • HIDAKA HIROSHI, TERADA KENTARO, YURIMOTO HISAYOSHI  日本地球化学会年会講演要旨集  61st-  (0)  133  2014   [Not refereed] [Not invited]  
    宇宙化学分野からは惑星探査,探査によってもたらされるリターンサンプルのキュレーション体制の強化,新しい分析手法の開発を伴うリターンサンプルのキャラクタリゼーション等を包含する大型研究計画を提案する。
  • INOUE TOORU, HAYASHI KOHEI, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  54th-  69  2013/10   [Not refereed] [Not invited]
  • Kitamura Keitaro, Umino Susumu, Kanayama Kyoko, Ishizuka O., Sakamoto N., Yurimoto H.  Programme and abstracts the Volcanological Society of Japan  2013-  (0)  2013/09   [Not refereed] [Not invited]
  • INOUE Toru, HAYASHI Kohei, YURIMOTO Hisayoshi  日本鉱物科学会年会講演要旨集  2013-  8  2013/09   [Not refereed] [Not invited]
  • YURIMOTO H.  Abstracts of Annual Meeting of the Geochemical Society of Japan  2013-  257  2013/09   [Not refereed] [Not invited]  
    私たちはイオンマイクロプローブ,同位体顕微鏡の開発を行ってきており,現在,同位体ナノスコープの開発に挑戦している.これらの分析法は相補的な効果があり,総合して活用することにより宇宙物質の成因が包括的に科学できる.今後は分光法による外惑星の軽元素の分光法による同位体分析の開発が必要である.また,ケロジェンの全構造解析のために,放射光の種々の分光分析・質量分析・NMR・クロマトグラフィーの分析技術とそれらを融合する新しいバイオインフォマティクスを開発するプロジェクトが重要である.
  • YURIMOTO HISAYOSHI, BAJO KEN'ICHI, ISHIHARA MORIO, UCHINO KIICHIRO, ITOSE SATORU, MATSUYA MIYUKI, KUDO MASATO  質量分析総合討論会講演要旨集  61st-  16  2013/09   [Not refereed] [Not invited]
  • MAGAMI KEN'ICHI, YURIMOTO NAOYOSHI  質量分析総合討論会講演要旨集  61st-  134  2013/09   [Not refereed] [Not invited]
  • ミノドロン酸の同位体顕微鏡を用いた骨組織分布と破骨細胞に対する影響
    佐々木 宗輝, 本郷 裕美, 小林 幸雄, 圦本 尚義, 網塚 憲生  Journal of Oral Biosciences Supplement  2013-  146  -146  2013/09   [Not refereed] [Not invited]
  • ミノドロン酸の同位体顕微鏡を用いた骨組織分布と破骨細胞に対する影響
    佐々木 宗輝, 本郷 裕美, 小林 幸雄, 圦本 尚義, 網塚 憲生  Journal of Oral Biosciences Supplement  2013-  135  -135  2013/09   [Not refereed] [Not invited]
  • OGASAWARA KIMI, SAKAMOTO NAOYA, ITO TOSHIAKI, YURIMOTO HISAYOSHI, NAITO SATOSHI, TAKANO JUMPEI  日本植物学会大会研究発表記録  77th-  167  2013/08   [Not refereed] [Not invited]
  • OTAKE TSUBASA, SAKAMOTO YUKI, ITO SHOICHI, YURIMOTO HISAYOSHI, KAKEGAWA TAKESHI  資源地質学会年会講演会講演要旨集  63rd-  34  2013/06   [Not refereed] [Not invited]
  • KUGA YUKARI, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI  日本土壌微生物学会講演要旨集  2013-  23  2013/06   [Not refereed] [Not invited]
  • SASAKI MUNEKI, HONGO YUMI, KOBAYASHI SACHIO, YURIMOTO HISAYOSHI, AMIZUKA NORIO  日本骨形態計測学会雑誌  23-  (1)  S81  -S81  2013/06   [Not refereed] [Not invited]
  • YURIMOTO HISAYOSHI  分析化学討論会講演要旨集  73rd-  24  2013/05   [Not refereed] [Not invited]
  • OGASAWARA KIMI, SAKAMOTO NAOYA, ITO TOSHIAKI, YURIMOTO HISAYOSHI, NAITO SATOSHI, TAKANO JUMPEI  日本植物生理学会年会要旨集  54th-  335  2013/03   [Not refereed] [Not invited]
  • YURIMOTO HISAYOSHI  日本地球化学会年会講演要旨集  60th-  200  2013   [Not refereed] [Not invited]
  • KITAMURA KEITARO, UMINO SUSUMU, KANAYAMA KYOKO, ISHIZUKA OSAMU, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI  日本火山学会講演予稿集  2013-  91  2013   [Not refereed] [Not invited]
  • Kitamura Keitaro, Umino Susumu, Kanayama Kyoko, Ishizuka O., Sakamoto N., Yurimoto H.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2013-  (0)  2013   [Not refereed] [Not invited]
  • Itoh Shoichi, Yanai Kaori, Russell Sara, Greenwood James, Hisayoshi Yurimoto  Abstracts of Annual Meeting of the Geochemical Society of Japan  60-  (0)  3  2013   [Not refereed] [Not invited]  
    隕石母天体内での流体(H2O)のふるまいは,これまで全く不明瞭であった.これら流体のふるまいに制約を与えるため,近年,リン酸塩鉱物の岩石学的,同位体的研究が盛んに行われてきた(e.g., Jones et al., 2011; Yanai et al., 2012). 本講演では,系統的に,熱変成度の異なるLL4-6のリン酸塩鉱物に含まれる微量結晶水の定量及び水素同位体組成を報告する予定である.
  • Bajo Ken-ichi, Sakaguchi Isao, Suzuki Taku, Itose Satoru, Matsuya Miyuki, Kudo Masato, Ishihara Morio, Uchino Kichiro, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  60-  (0)  8  2013   [Not refereed] [Not invited]  
    Nagao et al. (2011) によるはやぶさ試料の希ガス同位体分析は太陽風照射とそれに伴う太陽風起源He/Ne間の分別を明らかにした.しかし,希ガス分析は粒子一粒ごとの結果でありSTEM観察との直接比較を行うには希ガス分析事前にSTEM観察を行うなど,分析方法の工夫が必要である.そこで,我々が開発したポストイオン化二次イオン質量分析装置LIMAS(Laser Ionization Mass Nanoscope)を用いることで,希ガス同位体分析を数十nmスケールの空間分解能で行うことが可能となり得る.本発表では新しい局所希ガス同位体分析手法をもとに,イトカワ表層での太陽風照射の履歴に関して期待される結果について述べる.
  • 佐々木宗輝, 本郷裕美, 小林幸雄, 圦本尚義, 網塚憲生  Journal of Oral Biosciences Supplement (Web)  2013-  ROMBUNNO.O‐112 (WEB ONLY)  2013   [Not refereed] [Not invited]
  • YOSHIMURA S., NAKAMURA M., YURIMOTO H.  日本鉱物科学会年会講演要旨集  2012-  2012/09   [Not refereed] [Not invited]
  • YOSHIMURA SHUMPEI, NAKAMURA MICHIHIKO, YURIMOTO HISAYOSHI  日本鉱物科学会年会講演要旨集  2012-  (0)  29  2012/09   [Not refereed] [Not invited]  
    The carbon isotopic fractionation between CO2-rich fluid and granitic melt was determined to be Δf-m = +0.8‰ at 1200 °C and 10 kbar. Infrared spectrometry revealed that both CO2 molecule and CO32- are present in this melt. The carbon isotope fractionation is modelled as a linear function of the ratio of CO3-2 to CO2molecule.
  • YURIMOTO Hisayoshi, SAKAMOTO Naoya  顕微鏡 = Microscopy  47-  (2)  92  -97  2012/06   [Not refereed] [Not invited]
  • IRIMOTO HISAYOSHI  応用物理学関係連合講演会講演予稿集(CD-ROM)  59th-  ROMBUNNO.15P-B11-1  2012/02   [Not refereed] [Not invited]
  • SAKAGUCHI ISAO, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI, OHASHI NAOKI, HISHITA SHUN'ICHI  セラミックス基礎科学討論会講演要旨集  50th-  21  2012/01   [Not refereed] [Not invited]
  • Hashiguchi Minako, Kobayashi Sachio, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  59-  (0)  281  2012   [Not refereed] [Not invited]  
    本発表では,始原的隕石中の有機物の水素・窒素同位体組成,そして有機物の形状について報告する.マーチソン隕石 (CM2)とNWA 801隕石 (CR2)マトリックスから,マトリックスの同位体比よりDまたは15Nに富む有機物を発見した. マーチソン隕石とNWA 801隕石におけるDに富む有機物と15Nに富む有機物の割合から,水質変質の進行によってマーチソン隕石では有機物のDの過剰が優先的に消失したことが考えられた.Dまたは15Nに富む有機物の形状は,複数の粒子の集合体 (アグリゲイト)または単独の粒子であり,マーチソン隕石とNWA 801隕石の有機物には, (アグリゲイト/単独の粒子)比に違いが見られた.形状からDに富む有機物と15Nに富む有機物を判別することは出来ず,隕石中の有機物がその形成時に同位体比が一定の値であったとすると,(アグリゲイト/単独の粒子)比の違いは,隕石母天体周囲の環境あるいは集積プロセスの違いを反映している可能性がある.
  • Aicheng Zhang, Shoichi Itoh, Naoya Sakamoto, Hisayoshi Yurimoto, Rucheng Wang  Abstracts of Annual Meeting of the Geochemical Society of Japan  59-  (0)  2012   [Not refereed] [Not invited]  
    We report mineralogy, oxygen isotopic and rare-earth-element compositions of a sapphirine-bearing Al-rich chondrule (SARC) from the Dar al Gani (DaG) 978 ungrouped carbonaceous chondrite. Our results indicate that the precursor of SARC included Group II CAIs as components. Assimilation of incompletely melted amoeboid olivine aggregate also occurred during formation of the ferromagnesian rim in SARC.
  • Wakaki Shigeyuki, Itoh Shoichi, Tanaka Tsuyoshi, Yurimoto Hsayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  59-  (0)  294  2012   [Not refereed] [Not invited]  
    CAIとコンドリュールは、原始太陽系星雲内で異なる時間に異なる条件で溶融したと考えられているが、これらの物質の溶融を引き起こした物理的プロセスが同一であるか、その物理的プロセスの詳細は明らかになっていない。本研究では、CAI-コンドリュール複合物質の形成年代および溶融条件を明らかにする事を目的として、SIMSによるAl-Mg系同位体分析を行った。複合物質のオリビンと斜長石は、CAI形成後3.4Myに相当するisochronを形成した。一方で溶融残渣と考えられるスピネルは上記isochronとCanonical isochronとの中間に分布し、そのMg同位体組成は複合物質形成イベントによって不完全に(45-98%程度)リセットされたと考えられる。スピネルのみが溶け残る温度条件は岩石学的に1380-1480℃と見積もれる。スピネル中のMg拡散モデルから、溶融時間は50s-7hと見積もられた
  • Bajo Ken-ichi, Ebata Shingo, Fujioka Osamu, Sakaguchi Isao, Yurimoto Hisayoshi, Uchino Kichiro, Ishihara Morio, Itose Satoru, Matsuya Miyuki, Kudo Masato  Abstracts of Annual Meeting of the Geochemical Society of Japan  59-  (0)  300  2012   [Not refereed] [Not invited]  
    二次イオン質量分析は高い空間分解能と多元素の高感度な定量が出来るため微小領域の同位体分析において重用されている。しかしながら希ガスはイオン化ポテンシャルが高いことと含有量が微量であることから、天然試料のSIMSでの分析は不可能であった。そこで我々はLaser Ionization MAss nanoScopeを用いて希ガス同位体分析を天然試料に適応するための開発を行っている。この装置は一次イオンビームによりスパッタされた希ガス原子をフェムト秒レーザーによりポストイオン化させることが可能である。従来の希ガス局所分析の空間分解能は100 μm程度であったが、LIMASではサブミクロン(最高空間分解能10 nm)で分析が可能である。この装置を用いてレゴリスブレッチャの太陽風起源希ガスの2次元分布を分析することにより、小惑星表層を覆うレゴリスの形成過程を明らかにすることが本研究の主題である。
  • Ohtani E., Kuramoto K., Imamura T., Terada N., Watanabe S., Arakawa M., Ito T.  Planetary People  20-  (4)  349  -365  2011/12   [Not refereed] [Not invited]  
    「月惑星探査の来たる10年」検討では第一段階で5つのパネルの各分野に於ける第一級の科学について議論した.そのとりまとめを報告する.地球型惑星固体探査パネルでは,月惑星内部構造の解明,年代学・物質科学の展開による月惑星進化の解明,固体部分と結合した表層環境の変動性の解明,が挙げられた.地球型惑星大気・磁気圏探査パネルは複数学会に跨がる学際性を考慮して,提案内容に学会間で齟齬が生じないように現在も摺り合わせを進めている.本稿では主たる対象天体を火星にしぼって第一級の科学を論じる.小天体パネルでは始原的・より未分化な天体への段階的な探査と,発見段階から理解段階へ進むための同一小天体の再探査が提案された.木星型惑星・氷衛星・系外惑星パネルは広範な科学テーマの中から,木星の大気と磁気圏探査,氷衛星でのハビタブル環境の探査,系外惑星でも生命存在可能環境と生命兆候の発見について具体的な議論を行った.アストロバイオロジーパネルでは現実的な近未来の目標として火星生命探査を,長期的な目標として氷衛星・小天体生命探査を目指した観測装置開発が検討された.これらのまとめを元に「月惑星探査の来たる10年」検討は2011年7月より第二段階に移行し,ミッション提案・観測機器提案の応募を受け付けた.
  • YURIMOTO HISAYOSHI  現代化学  (489)  23  -28  2011/12   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi, ISHIHARA Morio, UCHINO Kiichiro, EBATA Shingo  應用物理  80-  (11)  979  -982  2011/11   [Not refereed] [Not invited]
  • INOUE TOORU, YABUKI TOMOMI, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  52nd-  25  2011/10   [Not refereed] [Not invited]
  • Sandford Scott A.  Abstracts Fall Meeting of the Japanese Society for Planetary Sciences  2011-  2011/10   [Not refereed] [Not invited]
  • Sandford Scott  Abstracts Fall Meeting of the Japanese Society for Planetary Sciences  2011-  2011/10   [Not refereed] [Not invited]
  • Tsuchiyama Akira, Uesugi Masayuki, Matsushima Takashi, Michikami Tatsuhiro, Kadono Toshihiko, Nakamura Tomoki, Uesugi Kentaro, Nakano Tsukasa, Sandford Scott, Noguchi Ryo, Matsumoto Toru, Matsuno Junya, Nagano Takashi, Imai Yuta, Takeuchi Akihisa, Suzuki Yoshio, Ogami Toshihiro, Katagiri Jun, Ebihara Mitsuru, Ireland Trevor, Kitajima Fumio, Nagao Keisuke, Naraoka Hiroshi, Noguchi Takaaki, Okazaki Ryuji, Yurimoto Hisayoshi, Zolensky Michael, Mukai Toshifumi, Abe Masanao, Yada Toru, Fujimura Akio, Yoshikawa Makoto, Kawaguchi Jun'ichiro  Annual Meeting of the Geological Society of Japan  2011-  (0)  1  -1  2011/09   [Not refereed] [Not invited]
  • INOUE Toru, YABUKI Tomomi, YURIMOTO Hisayoshi  日本鉱物科学会年会講演要旨集  2011-  228  2011/09   [Not refereed] [Not invited]  
    Water contents of Al-bearing minerals in the mantle transition zone and the lower mantle were determined in the systems pyrope - enstatite with H2O of 11.3 wt% and 18.7 wt% at pressures of 20-26 GPa and temperatures of 1473-1873K. The water contents of Al-bearing experimental products were measured by secondary ion mass spectrometry (SIMS) in Hokkaido University, and found the water contents as follows : perovskite ∼0.8 wt%, garnet ∼0.6 wt%, stishovite ∼1.4 wt%, phase D ∼22 wt%. These water contents were strongly related to the Al contents of these phases. Thus the water contents in the Earth' s mantle minerals are strongly related to the Al contents.
  • KIMURA(SUDA) HIROMI, KAJIHARA MAKOTO, SAKAMOTO NAOYA, KOBAYASHI SACHIO, IJIRO KUNIHARU, YURIMOTO HISAYOSHI, YAMATO HIDEYUKI  J Oral Biosci  53-  (Supplement)  84  2011/09   [Not refereed] [Not invited]
  • KIMURA(SUDA) HIROMI, KUWAHARA MIEKO, HIDAKA KOSUKE, KANAZAWA KYOSUKE, HONMA NORITSUGU, BANNAI KENJI, SUGANO MIKIO, KAJIHARA MAKOTO, ONISHI AKIHIRO, KOBAYASHI SACHIO, SAKAMOTO NAOYA, IJIRO KUNIHARU, YURIMOTO HISAYOSHI, YAMATO HIDEYUKI  バイオイメージング  20-  (2)  95  -96  2011/08   [Not refereed] [Not invited]
  • 女性研究者がリードするバイオイメージング 赤外イメージングおよび元素イメージングによる生体組織の解析
    木村 廣美[須田], 桑原 三恵子, 日高 公介, 金沢 恭祐, 本間 教嗣, 坂内 堅二, 菅野 三喜男, 梶原 誠, 大西 晃宏, 小林 幸雄, 坂本 直哉, 居城 邦治, 圦本 尚義, 大和 英之  バイオイメージング  20-  (2)  95  -96  2011/08   [Not refereed] [Not invited]
  • YURIMOTO HISAYOSHI  Isot News  (686)  17  -21  2011/06   [Not refereed] [Not invited]
  • HIDAKA KOSUKE, KUWAHARA MIEKO, KANAZAWA KYOSUKE, ONISHI AKIHIRO, BANNAI KENJI, SUGANO MIKIO, KOBAYASHI SACHIO, YURIMOTO HISAYOSHI, YAMATO HIDEYUKI, KIMURA(SUDA) HIROMI  高分子学会予稿集(CD-ROM)  60-  (1 Disk1)  ROMBUNNO.1PB148  2011/05   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi, Itoh Shoichi, Sakamoto Naoya, Kobayashi Sachio, Hashizume Ko, Tsuchiyama Akira, Seto Yusuke, T. R. Ireland, M. Zolensky, Nakamura Tomoki, Noguchi Takaaki, Nagao Keisuke, Ebihara Mitsuru, Naraoka Hiroshi, Okazaki Ryuichi, Kitajima Fumio, Mukai Toshifumi, Fujimura Akio, Abe Masanao, , , ,  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  171  -171  2011   [Not refereed] [Not invited]  
    太陽系形成期の研究は,主に隕石を参照することにより検証がおこなわれ,進展して来た.隕石は小惑星の破片であるといわれているが,母天体となる小惑星が確認されている隕石は一つもない.小惑星イトカワにタッチダウンした惑星探査機はやぶさが,昨年,小惑星イトカワの表面物質を地球に持ち帰った.採取された試料は,最大で数百ミクロンの微粒子であるが,これらの試料を分析することにより,小惑星と隕石との関係の一部が初めて明らかになっていくことが期待される. 本講演では,酸素同位体組成,マグネシウム同位体組成戸26Al,微量元素組成について報告する.
  • Ebata Shingo, Bajo Ken-ichi, Uchino Kiichiro, Ishihara Morio, Itose Satoru, Matsuya Miyuki, Kudo Masato, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  176  -176  2011   [Not refereed] [Not invited]  
    In sample-return missions, samples collected on planets or asteroids are returned to the Earth by space spacecrafts, and then analyzed in laboratories. However, amounts of samples would be limited. Here, we have developed a novel time-of-flight SNMS (TOF-SNMS) system with ultra-high sensitivity and ultra-high mass resolving power. This instrument would be effective for ultrahigh sensitive analysis of nano-size particles such as return samples.
  • Bajo Ken-ichi, Ebata Shingo, Uchino Kiichiro, Ishihara Morio, Itose Satoru, Matsuya Miyuki, Kudo Masato, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  177  -177  2011   [Not refereed] [Not invited]  
    二次イオン質量分析は高い空間分解能と多元素の高感度な定量が出来るため微小領域の同位体分析において重用されている。しかしながら希ガスはイオン化ポテンシャルが高いことと、含有量が極微量であることから二次イオン質量分析での分析は不可能であった。そこで発表者らは新たに開発された超高感度極微量質量分析システムを用いて希ガス同位体分析を試みている。このシステムでは一次イオンビームによりスパッタされた希ガス原子を高光子密度のレーザーを照射することにより希ガス原子をイオン化させることができる。発表者らは隕石中の太陽風起源希ガスに注目して実験を行っており、今後はSolar-gas-rich 隕石から太陽風起源希ガス同位体の検出を試みる予定である。
  • Kawasaki Noriyuki, Sakamoto Naoya, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  178  -178  2011   [Not refereed] [Not invited]  
    本研究では,エフレモフカCV3コンドライト中のFluffy Type A CAIの岩石学的記載と,累帯構造を持つメリライト結晶の固溶体組成および酸素同位体組成の分析を行った.本CAIは,内部にWark-Loveringリムの断片のような構造があり,領域によって岩石学的特徴が異なることから,大きく4つのドメインに分類できる.各ドメインはその構造,鉱物組合せなどが異なり,特に2つのドメインのメリライトの固溶体組成と酸素同位体組成に違いが見られた.各ドメインの境界は大部分はWark-Loveringリムやその断片のような構造で区切られており,各ドメインは別々に形成され集合したものであると考えられる.
  • Katayama Juri, Itoh Shoichi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  179  -179  2011   [Not refereed] [Not invited]  
    Fluffy Type A CAI (FTA)の3つのメリライト単結晶中の逆累帯構造にともなう酸素同位体組成変化を評価した.各結晶コア部の酸素同位体組成は異なり,累帯構造に伴う酸素同位体組成の変化の大きさやそのゾーニングの幅も異なっていた.本講演では,累帯構造に対応して単結晶内に存在した酸素同位体組成の変化に着目し,Fluffy Type A CAIの形成環境を評価する.
  • Itoh Shoichi, Simon Steven, Grossman Lawrence, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  223  -223  2011   [Not refereed] [Not invited]  
    本講演では,部分溶融を経験している二つのTypeB CAI(Golfball, TS34)の酸素同位体組成及びAl-Mg同位体組成を組み合わせ,部分溶融による鉱物アイソクロンへの影響を議論する.これまで,分析精度の制約により,低いAl-Mg比をもつ鉱物のアイソクロンは不明瞭であったため,本研究では,二次イオン質量分析計による高精度局所同位体分析により,結晶化時期が異なると考えられている低いAl/Mg比をもつ各鉱物のアイソクロンを含めた鉱物アイソクロンを議論し,CAIの部分溶融と年代の関係を議論する.
  • YURIMOTO HISAYOSHI, ITO SHOICHI, SAKAMOTO NAOYA, KOBAYASHI SACHIO, HASHIZUME KO, TSUCHIYAMA AKIRA, SETO YUSUKE, IRELAND T. R., ZOLENSKY M., NAKAMURA TOMOKI, NOGUCHI TAKAAKI, NAGAO KEISUKE, EBIHARA MITSURU, NARAOKA HIROSHI, OKAZAKI RYUICHI, KITAJIMA FUMIO, MUKAI TOSHIFUMI, FUJIMURA AKIO, ABE MASANAO, YADA TOORU, UESUGI MASAYUKI, YOSHIKAWA MAKOTO, KAWAGUCHI JUN'ICHIRO  日本地球化学会年会講演要旨集  58th-  179  2011   [Not refereed] [Not invited]
  • Hashiguchi Minako, Sachio Kobayashi, Hisayoshi Yurimoto  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  290  -290  2011   [Not refereed] [Not invited]  
    始原的隕石中の重水素に富む有機物と水素同位体異常を示さない有機物に対し,ラマン分光分析を行った.重水素に富む有機物とマトリックスのラマンスペクトルには,どちらも,Gバンド (約1580 cm-1)とDバンド (約1370 cm-1)が見られた.これは,隕石有機物が示す典型的なラマンスペクトルである.また,重水素に富む有機物の方が,水素同位体異常を示さない有機物と比較してDバンドの半値幅, DバンドとGバンドの強度比が小さいことが分かった.この結果は,重水素に富む有機物と水素同位体異常を示さない有機物とでは構造が異なることを示唆しており,前者の方が少し構造が単純であると考えられる.
  • Inoue Toru, Yabuki Tomomi, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2011-  (0)  224  -224  2011   [Not refereed] [Not invited]  
    Water contents of Al-bearing minerals in the mantle transition zone and the lower mantle were determined in the systems pyrope - enstatite with H2O of 11.3 wt% and 18.7 wt% at pressures of 20-26 GPa and temperatures of 1473-1873K. The water contents of Al-bearing experimental products were measured by secondary ion mass spectrometry (SIMS) in Hokkaido University, and found the water contents as follows : perovskite ∼0.8 wt%, garnet ∼0.6 wt%, stishovite ∼1.4 wt%, phase D ∼22 wt%. These water contents were strongly related to the Al contents of these phases. Thus the water contents in the Earth' s mantle minerals are strongly related to the Al contents.
  • Tsuchiyama Akira, Uesugi Masayuki, Matsushima Takashi, Michikami Tatsuhiro, kadono Toshihiko, Nakamura Tomoki, Uesugi Kentaro, Nakano Tsukasa, Sandford Scott A, Noguchi Ryo, Matsumoto Toru, Matsuno Junya, Nagano Takashi, Imai Yuta, Takeuchi Akihisa, Yoshio Suzuki, Ogami Toshihiro, Katagiri Jun, Ebihar Mitsuru, Ireland Trevor, Kitajima Fumio, Nagao Keisuke, Naraoka Hiroshi, Noguchi Takaaki, Okazaki Ryuji, Yurimoto Hisayoshi, Zolensky Michael, Hayabusa Curation Team  Abstracts of Annual Meeting of the Geochemical Society of Japan  58-  (0)  169  -169  2011   [Not refereed] [Not invited]  
    Particles collected by the Hayabusa spacecraft are considered as regolith on the surface of asteroid Itokawa. Three-dimensional structures and shapes of these particles were obtained using X-ray microtomography at Spring-8 in the preliminary examination of Hayabusa sample. The modal abundance of minerals and density of whole particles are similar to those of LL chondrites. Any melting textures, such as agglutinates found in Luna regolith, were not observed. Size distribution and three-dimensional shape distribution are also different from those of Luna regolith. Based on these data, the formation and evolution of the regolith particles will be discussed.
  • Abe Kenichi, Sakamoto Naoya, Yurimoto Hisayoshi  Planetary People  19-  (4)  268  -272  2010/12   [Not refereed] [Not invited]  
    宇宙シンプレクタイト(COS)は現在知られている太陽系物質の中で最も重い酸素同位体組成を持ち,太陽系初期の水に由来することが示唆されている.COSが原子数比でFe:O:S≈4:4:1の特徴的な化学組成を保持していることを利用して,FE-SEM-EDSによりAcfer 094隕石の広範囲かつ高空間分解能なX線元素マッピングを行い,COSを探索した.1mm四方の元素マップを7面取得し,1〜260μm^2の大きさのCOSを66個同定した.COSの平均面積は32μm^2,個数存在度は9個/mm^2であり,Acfer 094隕石マトリックスにおいて体積存在度521ppmで普遍的に存在することが明らかになった.
  • EBATA SHINGO, ISHIHARA MORIO, KUMONDAI KOSUKE, MIBUKA RYO, UCHINO KIICHIRO, YURIMOTO HISAYOSHI  日本惑星科学会誌 遊・星・人  19-  (4)  295  -304  2010/12   [Not refereed] [Not invited]
  • Ebata Shingo, Ishihara Morio, Kumondai Kousuke, Mibuka Ryo, Uchino Kiichiro, Yurimoto Hisayoshi  Planetary People  19-  (4)  295  -304  2010/12   [Not refereed] [Not invited]  
    本研究では,これまでにない性能を持った質量分析システムの開発を行なっている.同システムでは,フェムト秒レーザーを用いたポストイオン化技術が採用され,従来と比べて100倍の感度向上が確認された.また,質量分解能は21,000以上であることが確認され,さらに空間分解能40nmのイメージングが実現された.これらのことから,本システムを用いることによって,サンプルリターンミッションによって持ち帰られた貴重なサンプルを超高感度,超高質量分解能,超高空間分解能で分析することが可能になると期待される.
  • ABE KEN'ICHI, SAKAMOTO NAOYA, YURIMOTO HISAYOSHI  日本惑星科学会誌 遊・星・人  19-  (4)  268  -272  2010/12   [Not refereed] [Not invited]
  • TSUCHIYAMA Akira, EBIHARA Mitsuru, KITAJIMA Fumio, NAGAO Keisuke, NAKAMURA Tomoki, NARAOKA Hiroshi, NOGUCHI Takaaki, OKAZAKI Ryuji, UESUGI Masayuki, YURIMOTO Hisayoshi, HASPET members  日本鉱物科学会年会講演要旨集  2010-  65  2010/09   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi, SUGITA Seiji, TACHIBANA Shogo  日本鉱物科学会年会講演要旨集  2010-  69  2010/09   [Not refereed] [Not invited]
  • SETO Yusuke, TOH Shoichi, SAKAMOTO Naoya, YURIMOTO Hisayoshi  日本鉱物科学会年会講演要旨集  2010-  157  2010/09   [Not refereed] [Not invited]
  • MOTAI Satoko, NAGAI Takaya, SOWA Kohki, WATANABE Tsuyoshi, SAKAMOTO Naoya, YURIMOTO Hisayoshi  日本鉱物科学会年会講演要旨集  2010-  84  2010/09   [Not refereed] [Not invited]
  • MIYAWAKI RITSURO, SHIMAZAKI HIDEHIKO, SHIGEOKA MASAKO, YOKOYAMA KAZUMI, MATSUBARA SATOSHI, YURIMOTO HISAYOSHI, YAN ZUMIN  粘土科学討論会講演要旨集  54th-  58  -59  2010/09   [Not refereed] [Not invited]
  • YAMAMOTO KOSUKE, SAKAMOTO NAOYA, NISHIO TAKASHI, IJIRO KUNIHARU, YURIMOTO HISAYOSHI  日本分析化学会年会講演要旨集  59th-  168  2010/09   [Not refereed] [Not invited]
  • KIMURA(SUDA) HIROMI, KAJIHARA MAKOTO, SAKAMOTO NAOYA, KOBAYASHI SACHIO, IJIRO KUNIHARU, YURIMOTO HISAYOSHI, YAMATO HIDEYUKI  高分子学会予稿集(CD-ROM)  59-  (2 Disk1)  ROMBUNNO.2PE123  2010/09   [Not refereed] [Not invited]
  • YAMAZAKI Daisuke, HEGODA Chamathni, DOHMEN Ralf, YURIMOTO Hisayoshi, CHAKRABORTY Sumit, KATSURA Tomoo  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • KOBAYASHI S., NAGASHIMA K., TONOTANI A., SAKAMOTO N., ITOH S., RUSSELL S. S., KROT Alexander N., YURIMOTO H.  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • ABE K., SAKAMOTO N., KOJIMA H., KROT A. N., RUSSELL S. S., YURIMOTO H.  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • ITOH S., SIMON S. B., GROSSMAN L., YURIMOTO H.  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • WAKAKI S., ITOH S., TANAKA T., YURIMOTO H.  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • SAKAMOTO Naoya, AOYAMA Satoshi, KAWAHITO Shoji, YURIMOTO Hisayoshi  日本鉱物科学会年会講演要旨集  2009-  2010/04   [Not refereed] [Not invited]
  • Seto Yusuke, Toh Shoichi, Sakamoto Naoya, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2010-  (0)  153  -153  2010   [Not refereed] [Not invited]  
    In the present study, we report microstructure of the isotopically anomalous material COS in the carbonaceous chondrite Acfer 094 using transmission electron microscopy. The TEM observations shows that COS grain consists of magnetite + pyrrhotite (+ minor pentlandite) with a symplectitic texture in tens nm scale. The grain boundaries between magnetite and pyrrhotite are smoothly rounded, and both phases are directly contacted without amorphous regions. Such a nanometer scale inter-growth texture may suggest the simultaneous and rapid crystal growth of the constituent minerals at the time of formation.
  • Katayama Juri, Itoh Shoichi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  57-  (0)  266  -266  2010   [Not refereed] [Not invited]  
    Fluffy TypeA CAIのメリライト結晶の鉱物学的組織を解析し,固溶体成分の累帯構造に基づき,酸素同位体非平衡を再検討したので報告する.逆累帯構造をもつメリライト結晶を8個発見し,どの結晶も連続的にオケルマナイト成分(ak5)が3-25%の範囲で変化していた.Wark-Lovering (WL)リムに接していない鉱物間では,それぞれ異なるak組成範囲を示していたが,鉱物間の酸素同位体組成は,分析誤差範囲内でどれもほぼ均一な組成を示した.一方,WLリムに接している結晶3個は、鉱物内に酸素同位体非平衡な分布を示した(Δ17O= -20~ -5‰)。本講演では,累帯構造に基づいて単結晶内に存在した酸素同位体分布の変化に注目し, Fluffy Type A CAIの成因を評価していく。
  • Motai Satoko, Nagai Takaya, Sowa Kohuki, Watanabe Tsuyoshi, Sakamoto Naoya, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2010-  (0)  82  -82  2010   [Not refereed] [Not invited]  
    Aragonite (CaCO3) makes up coral skeletons. The variation of the trace elements and isotope in coral skeletons is used for reconstructing paleoclimate. The process of skeleton growth plays an important role for interpretation of those data, but Aragonite is a metastable phase under a coral growing environment and the nucleation and growth process has not been raveled clearly. Here we will propose a possible process through observations of mineral texture on nano to micron scale.The observed materials are massive coral (Porites lobata) and arborescens coral (Acropora nobilis). Each thin section was observed its texture using optical microscope and ATEM for texture analysis and FE-SEM for element distribution.
  • YURIMOTO HISAYOSHI  宇宙航空研究開発機構特別資料 JAXA-SP-  (10-001(CD-ROM))  DOITAINOIMEJINGU  2010   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi, Sugita Seiji, Tachibana Shogo  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2010-  (0)  68  -68  2010   [Not refereed] [Not invited]  
    Next generation plan of sample return missions from primitive asteroids and Mars is presented. In order to succeed the missions, we propose that new research organization style of an industry-university cooperation.
  • KIMURA(SUDA) HIROMI, KAJIHARA MAKOTO, SAKAMOTO NAOYA, KOBAYASHI SACHIO, IJIRO KUNIHARU, YURIMOTO HISAYOSHI, YAMATO HIDEYUKI  日本骨代謝学会学術集会プログラム抄録集  28th-  163  2010   [Not refereed] [Not invited]
  • Tsuchiyama Akira, Ebihara Mitsuru, Kitajima Fumio, Nagao Keisuke, Nakamura Tomoki, Naraoka Hiroshi, Noguchi Takaaki, Okazaki Ryuji, Uesugi Masayuki, Yurimoto Hisayoshi, Members HASPET  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2010-  (0)  64  -64  2010   [Not refereed] [Not invited]  
    The Hayabusa spacecraft arrived at the asteroid Itokawa in November 2005, and the sample capsule was successfully retrieved in June, 2010. Although the sample collection was not made by normal operations, it is expected that a small amount of sample, at least a few particles of approximately a few tens of micron meters in size, were collected from the asteroid surface. If the sample is present in the capsule, it will be examined preliminary within one year prior to detailed analysis phase. The following scientific achievements will be expected; (a) characterization of the surface material of Itokawa (LL5 or 6 chondrite as expected from reflectance spectrum observation), (b) processes on an ancestor body of Itokawa and accretion into Itokawa (brecciation, degree of impact, etc.), (c) interaction with space environment (proof of space weathering, isotopic composition of solar wind oxygen, etc.), and (d) materials fallen onto the surface (e.g., organic materials without contamination on the earth).
  • YAMAGUCHI NORIKO, INOUE JUN, SUGIYAMA SHINJI, KOBAYASHI SACHIO, YURIMOTO HISAYOSHI, HIRADATE SHUNTARO  日本ペドロジー学会大会講演要旨集  49th-  27  2010   [Not refereed] [Not invited]
  • Miyawaki Ritsuro, Shimazaki Hidehiko, Shigeoka Masako, Yokoyama Kazumi, Matsubara Satoshi, Yurimoto Hisayoshi, Yang Zhuming  Abstracts of annual meeting of The Clay Science Society of Japan  54-  (0)  A11  -A11  2010   [Not refereed] [Not invited]  
    Fluorotetraferriphlogopite (KMg3Fe3+Si3O10F2) and fluorokinoshitalite (BaMg3Al2Si2O10F2) occur as subhedral to euhedral, platy crystals in metamorphosed carbonate rocks from the South ore body of the East Mine, Bayan Obo, Inner Mongolia, China.
  • YURIMOTO HISAYOSHI  日本分析化学会年会講演要旨集  58th-  451  2009/09   [Not refereed] [Not invited]
  • MIYAWAKI RITSURO, SHIMAZAKI HIDEHIKO, SHIGEOKA MASAKO, YOKOYAMA KAZUMI, MATSUBARA SATOSHI, YURIMOTO HISAYOSHI  粘土科学討論会講演要旨集  53rd-  (0)  18  -19  2009/09   [Not refereed] [Not invited]  
    Yangzhumingite occurs in metamorphosed carbonate rock from Bayan Obo, Inner Mongolia, China. Electron micoprobe and SIMS anlyses gave an emprical formula as (K0.70Li0.30Na0.01)(Mg2.48Fe0.06)(Si3.96Al0.03)O10[F1.92(OH)0.08]. Yangzhumingite is monoclinic (C2/m) with lattice parameters of a = 5.249(4), b = 9.095(5), c = 10.142(5) Å, β = 99.96(6)˚, V = 476.9(5)Å3 and Z = 2.
  • YURIMOTO Hisayoshi  臨床化学  38-  (3)  272  -279  2009/07   [Not refereed] [Not invited]
  • YURIMOTO HISAYOSHI  臨床化学  38-  (3)  272  -279  2009/07   [Not refereed] [Not invited]
  • Yamazaki Daisuke, Chamathni Hegoda, Ralf Dohmen, Yurimoto Hisayoshi, Sumit Chakraborty, Katsura Tomoo  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  193  -193  2009   [Not refereed] [Not invited]  
    In this study, we determine the diffusivity of silicon in forsterite at high pressure and temperature to understand the effect of pressure on diffusivity.We performed high-pressure experiments using a Kawai-type multianvil apparatus. In the experiments, we used single crystal of forsterite as starting material with coating of 29Si-enriched Mg2SiO4 on the polished surface. Thick coating layer (200-300 nm) can maintain the isotope composition constant at the surface during diffusion annealing at pressures of 3, 8, 13 GPa and temperatures of 1600 and 1800 K for 3-60 hours. After high-pressure experiments, the recovered samples were analyzed by a secondary ion mass spectroscopy (SIMS) to obtain the variation of isotope concentration with depth from the crystal surface. Self-diffusion coefficient at 13 GPa and 1600 K is preliminarily estimated to be D=7x10-21 m2/s.
  • Kobayashi Sachio, Nagashima Kazuhide, Tonotani Azusa, Sakamoto Naoya, Itoh Shoichi, Russell S. S., Krot A. N., Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  217  -217  2009   [Not refereed] [Not invited]  
    Presolar grain survey was performed with 2-D in-situ isotope microscopy in carbonaceous and ordinary chondrites of various chemical groups, and various alteration, and metamorphic degrees. The sizes, and chemical compositions of presolar grains were studied with FE-SEM-EDS. A total 56 C-anomalous and 125 O-anomalous grains were found as presolar SiC, graphite, oxide, and silicate. Most of silicates were Fe-rich olivine. The various abundances of presolar silicates among carbonaceous chondrites indicate the destruction of presolar silicates by the parent body process. The lower abundances of presolar silicates in the least metamorphosed ordinary chondrites than carbonaceous chondrites suggests the destruction of silicates by nebular process in ordinary chondrite forming rigion.
  • Abe Ken-ichi, Sakamoto Naoya, Kojima Hideyasu, Krot A. N., Russell S. S., Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  218  -218  2009   [Not refereed] [Not invited]  
    Carbonaceous chondrite Acfer 094 is beliebed to one of the most primitive meteorites. This meteorite contains highly abundance of presolar grains and cosmic symplectite (COS) in the matrix. The COS has not been discovered in other carbonaceous chondrites. The uniqueness of Acfer 094 may be appeared in chemical characteristics of the matrix. In this report, we observed variations of chemical composition of fine-grained matrices among various carbonaceous chondrite groups to compare with Acfer 094. As a result, Al, S and Ca contents of fine-grained matrix minerals are highly variable among the carbonaceous chondrite groups. Acfer 094 matrix has both higher ratios of S/Al and Ca/Al than most chondrite groups. Such difference may result from micro scale elemental redistribution by aqueous and thermal metamorphism. This approach may be useful to classification of chondrite matrix to identify the pristine nature.
  • YURIMOTO Hisayoshi, MIURA Yayoi N.  地球化学  43-  (4)  115  -116  2009   [Not refereed] [Not invited]  
    This special issue of "Chikyu Kagaku" contains five papers from three sessions for cosmochemistry, "Cosmochemistry of extraterrestrial materials: From presolar history to early solar history", "Origin and evolution of Moon, Mars and small bodies in the solar system", and "Analytical technique, analytical organization and the scientific results of a new age of sample return mission", in the annual meeting of the Geochemical Society of Japan 2008. The five papers cover several topics on formation of water molecules in circum stellar environments, noble gas compositions of individual chondrules, discovery of chondrules from a comet sample, new analytical technique of extraterrestrial organics, and advances of lunar science under the cosmochemical view. These papers should be helpful to understand the trends of current research subjects of cosmochemistry. We hope this special issue could act as useful media for the cosmochemical community and the new comers to this research field.
  • ITOH SHOICHI, Steven Simon, Lawrence Grossman, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  56-  (0)  69  -69  2009   [Not refereed] [Not invited]  
    From petrographic study, a large Allende type B inclusion, Golfball has experienced at least two melting events. In the present study, we report preliminary results of oxygen and Al-Mg isotopic measurements of spinel and melilite in Golfball to determine ages of the multiple melting events and the oxygen isotopic composition of each melt. Delta O-18= -50 to -40permil for spinel, and the oxygen isotopic composition of melilite is distinct in each petrographic occurrence: Delta O-18= -20 to -10permil for gehlenitic core melilite and Delta O-18= ~0permil for melilite in the rim. Two isochrons are defined by the Al-Mg data. The gehlenitic core melilite and rim melilite yield initial 26Al/27Al ratios of 4.9+-0.8 and 1.9+-1.2x10-5, respectively. The age difference between the two isochrons is calculated to be about 1 My. From the chronological and the previous petrographic studies, we discuss the crystallization history of Golfball.
  • SAKAMOTO NAOYA, AOYAMA SATOSHI, KAWAHITO SHOJI, YURIMOTO HISAYOSHI  日本鉱物科学会年会講演要旨集  2009-  236  2009   [Not refereed] [Not invited]
  • Itoh Shoichi, Simon Steven, Grossman Lawrence, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  219  -219  2009   [Not refereed] [Not invited]  
    From petrographic study, a large Allende type B inclusion, Golfball has experienced at least two melting events. In the present study, we report preliminary results of oxygen and Al-Mg isotopic measurements of spinel and melilite in Golfball to determine ages of the multiple melting events and the oxygen isotopic composition of each melt. Delta O-18= -50 to -40permil for spinel, and the oxygen isotopic composition of melilite is distinct in each petrographic occurrence, Delta O-18= -20 to -10permil for gehlenitic core melilite and Delta O-18= ∼0permil for melilite in the rim. Two isochrons are defined by the Al-Mg data. The gehlenitic core melilite and rim melilite yield initial 26Al/27Al ratios of 4.9±0.8 and 1.9±1.2 x 10-5, respectively. The age difference between the two isochrons is calculated to be about 1 My. From the chronological and the previous petrographic studies, we discuss the crystallization history of Golfball.
  • Sakamoto Naoya, Aoyama Satoshi, Kawahito Shoji, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  230  -230  2009   [Not refereed] [Not invited]  
    High-sensitivity ion imager corresponding to real-time readout with 250000 pixels is developed. The output signal fluctuation of the pixel caused by 1 incident ion was 150µV/ion pixel which is 5 times improved by adopting smaller pixel capacitance. In order to reduce the readout noise, multiple signal-sampling mechanism was incorporated. The readout noise was achieved to 250 µV corresponding to 1.7 ions with 16 times signal-sampling. The readout speed was achieved to 12.5 frames/sec with single sampling and 8.3 frames/sec with 16 times signal-sampling. The read noise is independent of read out speed and now optimizing with multiple signal-sampling mechanism. Therefore, real-time single ion detection is expected if all the parameters become optimized.
  • YURIMOTO HISAYOSHI  日本地球化学会年会講演要旨集  56th-  XII  2009   [Not refereed] [Not invited]
  • Wakaki Shigeyuki, Itoh Shoichi, Tanaka Tsuyoshi, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2009-  (0)  220  -220  2009   [Not refereed] [Not invited]  
    A compound CAI found in the Allende meteorite was investigated for its formation processes by means of petrology, chemical composition and oxygen isotopic compositions. The inferred formation processes are as follows: 1) condensation of the precursor CAI from 16O-rich nebula gas, 2) multiple melting of the precursor CAI, 3) mixing of the precursor CAI with a chondrule-like material by melting under slightly 16O-rich nebula gas, 4) chondrule-like rim formation.
  • YURIMOTO HISAYOSHI  金属  78-  (11)  1024  -1028  2008/11   [Not refereed] [Not invited]
  • 圦本 尚義  Materials science & technology  78-  (11)  1024  -1028  2008/11   [Not refereed] [Not invited]  
    最近、隕石中に太陽系誕生以前の物質が含まれていることが明らかになった。この物質は化学組成からでは判別することができず、同位体組成によってのみ特定できる。この物質の研究を進めることにより、太陽系の起源でとぎれていた我々の歴史が宇宙史の中に位置づけられる日が来るだろう。
  • Yurimoto Hisayoshi  日本地質学会学術大会講演要旨  115-  2008/09   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi  Annual Meeting of the Geological Society of Japan  2008-  (0)  52  -52  2008/09   [Not refereed] [Not invited]
  • Itoh Shoichi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  55-  (0)  377  -377  2008/01   [Not refereed] [Not invited]  
    CaとAlに富む包有物(CAI)は、太陽系初期の時代から保存された物質であり、様々な複数回急加熱イベントを通じて、それより前に存在していた固体の熱加工により形成した。しかし,その間隔や期間は,不明瞭であった。本講演では、CAI構成鉱物に対して,約10ミクロン領域の短寿命核種26Alを用いた高精度年代測定の結果を報告する。個々のCAI形成期間は多様であり(10-50万年),16O-richな星雲ガス環境と16O-poorな星雲ガス環境が変動し,数万年以内でスイッチングしていた場合の存在した。
  • YURIMOTO HISAYOSHI  パリティ  23-  (1)  62  -64  2008/01   [Not refereed] [Not invited]
  • Seto Yusuke, Sakamoto Naoya, Fujino Kiyoshi, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2008-  (0)  206  -206  2008   [Not refereed] [Not invited]  
    We report mineral characterization of the isotopically anomalous material "COS" in the carbonaceous chondrite Acfer 094 using synchrotron radiation X-ray diffraction analysis and transmission electron microscopy. The results show following clear differences between the samples having high Ni content (High-Ni COS) and low Ni content (low-Ni COS); (1) The high-Ni COS grain consists of magnetite + pentlandite, while the low-Ni one consists of magnetite + pyrrhotite. (2) The high-Ni one is an aggregate of magnetite-pentlandite showing a symplectitic texture in tens nm scale, while the low-Ni one is an aggregate consisting of idiomorphic magnetite (∼100nm) and pyrrhotite (∼50nm) grains.We infer that the COS grains were formed by sulfurization and oxidization of metal grains. The chemical and micro-structural differences are probably reflected in the texture and the chemistry of precursor materials before the oxidization.
  • Ebata Shingo, Sakamoto Naoya, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  55-  (0)  375  -375  2008   [Not refereed] [Not invited]  
    プレソーラー粒子は太陽系形成以前に存在した太陽系を作る材料粒子であり、単独でマトリックス中に埋まっている。2007年江端らによってカンラン石や金属鉄とともにFeSで囲まれていたプレソーラーSiC粒子(SEC_ALH07)がEH3コンドライトから発見された。本研究では、周囲の組織の起源を解明する事を目的とし周囲を取り囲んでいるFeSの硫黄同位体組成分析を行った。‹BR›FeSの硫黄同位体組成は、δ‹SUP›33‹/SUP›S=-71±45‰, δ‹SUP›34‹/SUP›S=-48±56‰, δ‹SUP›36‹/SUP›S=27±173‰(誤差1σ)であった。δ‹SUP›34‹/SUB›S, δ‹SUP›36‹/SUP›Sの同位体組成は2 σの誤差内で太陽系の同位体組成と同じである事を示す。また、江端らの酸素同位体測定の報告によると内包されているカンラン石は太陽の同位体組成と同じであった。これらの結果は、周囲の硫化物はプレソーラーSiC粒子を核としてカンラン石や金属鉄と共に原始太陽系内において形成されたものである事を示唆する。
  • SETO YUSUKE, SAKAMOTO NAOYA, FUJINO KIYOSHI, YURIMOTO HISAYOSHI  日本鉱物科学会年会講演要旨集  2008-  212  2008   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi, , ,  Abstracts of Annual Meeting of the Geochemical Society of Japan  55-  (0)  378  -378  2008   [Not refereed] [Not invited]  
    原始太陽の酸素同位体組成は惑星の卵による太陽への汚染が太陽系進化過程において顕著ではなかった事を示す.また.原始太陽の酸素同位体比は太陽大気から求めた元素存在度が太陽系の平均元素存在度である事を保証している.
  • YURIMOTO HISAYOSHI  質量分析総合討論会講演要旨集  56th-  228  -229  2008   [Not refereed] [Not invited]
  • ISHIHARA MORIO, KUMONDAI KOSUKE, MIBUKA RYO, UCHINO KIICHIRO, YURIMOTO HISAYOSHI  質量分析総合討論会講演要旨集  56th-  36  -37  2008   [Not refereed] [Not invited]
  • Motai Satoko, Nagai Takaya, Sakamoto Naoya, Sowa Kohki, Watanabe Tuyoshi, Yurimoto Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2008-  (0)  175  -175  2008   [Not refereed] [Not invited]  
    Mineral phase identification of the coral skeletal microstructure is important for reconstructing the paleo-climate. Especially, chemical composition of Porites sp. is widely used as a paleo-environment variant. For example, it is believed that Sr/Ca ratio in coral skeletons is sensitive to temperature of seawater. Recently, Greegor et al. (1997) reported that as much as 40% of strontium (Sr) in coral aragonite existed as a SrCO3 end member by using XANES and EXAFS. This should be a very serious problem, when we apply the Sr/Ca ratio to reconstruct the paleo-environment. However, since there has been no direct mineral identification of SrCO3, we have carefully observed Porites sp. by FE-ASEM and ATEM in order to identify mineral phases in the coral skeletal.
  • 伊藤正一, 圦本尚義  日本地球化学会年会講演要旨集  55th-  409  2008   [Not refereed] [Not invited]
  • KATSUDA MASANORI, INOUE TOORU, IRIFUNE TETSUO, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  48th-  103  2007/11   [Not refereed] [Not invited]
  • SETO Yusuke, SAKAMOTO Naoya, YURIMOTO Hisayoshi, FUJINO Kiyoshi  日本鉱物学会・学術講演会,日本岩石鉱物鉱床学会学術講演会講演要旨集  2007-  2007/09   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2007-  6  2007/09   [Not refereed] [Not invited]  
    New technology of mass spectrometry for isotope analyses has been greatly advanced for recent years. The advances are especially for improvements of precision and for microanalysis. Precisions of isotope ratios have been improved by using an inductively coupled plasma mass spectrometer with multiple ion collectors. Capabilities of microanalysis have been improved by secondary ion mass spectrometry. These advances introduce new insights for origin of the Solar System and evolution of the Earth.
  • MIBUKA RYO, KURIHARA SHINJI, SAFWAT HASSABALLA, UCHINO KIICHIRO, YURIMOTO HISAYOSHI, TODOKORO RYOTARO, KUMONDAI KOSUKE, ISHIHARA MORIO  質量分析総合討論会講演要旨集  55th-  342  -343  2007/05   [Not refereed] [Not invited]
  • TODOKORO RYUTARO, KUMONDAI KOSUKE, MIBUKA RYO, KURIHARA SHINJI, UCHINO KIICHIRO, YURIMOTO HISAYOSHI, ISHIHARA MORIO  質量分析総合討論会講演要旨集  55th-  284  -285  2007/05   [Not refereed] [Not invited]
  • YURIMOTO NAOYOSHI  日本顕微鏡学会北海道支部学術講演会プログラム・予稿集  2006-  7  2007/02   [Not refereed] [Not invited]
  • Seto Yusuke, Sakamoto Naoya, Yurimoto Hisayoshi, Fujino Kiyoshi  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2007-  (0)  75  -75  2007   [Not refereed] [Not invited]  
    最近、炭素質コンドライトAcfer094中に17,18Oに富む物質が発見された。この物質は"New-PCP"と呼ばれ、これまで報告されている惑星物質の中でもっとも17,18Oの値が高い物質である。本研究ではこの物質の詳細な鉱物学的記載をおこなった。実験の結果、この物質は直径100-300nm程度の大きさの粒子で構成されており、その粒子の内部にはマグネタイトとペントランダイトの虫食い状組織が形成されていた。この組織は金属鉄の硫化、酸化反応によって形成されたと考えられる。
  • Watanabe Tsuyoshi, Sowa Koki, Sakamoto Naoya, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  54-  (0)  219  -219  2007   [Not refereed] [Not invited]  
    Massive corals have been widely used as proxies for past changes in sea surface temperature (SST) of the tropical and subtropical oceans because the oxygen isotopic and strontium/calcium (Sr/Ca) ratios of their aragonitic skeletons are believed to vary as a function of the temperature of the ambient seawater. However, recent microanalytical studies using secondary ion mass spectrometry (SIMS) have revealed large chemical heterogeneities for Sr/Ca and oxygen isotopic ratios in coral skeleton, which cannot be explained by temperature variation (e.g. Meibom et al., 2004, Rollin-Bard, et al., 2003)
  • WATANABE TAKESHI, SOWA KOKI, SAKAMOTO NAOYA, YORIMOTO YORIYOSHI  日本地球化学会年会講演要旨集  54th-  239  2007   [Not refereed] [Not invited]
  • KATSUDA MASANORI, INOUE TOORU, IRIFUNE TETSUO, YURIMOTO HISAYOSHI  高圧討論会講演要旨集  47th-  133  2006/10   [Not refereed] [Not invited]
  • NAKAMURA KEITA, KATO MARIKO, TANSHO RYOJI, FUJIMOTO MASAKI, IDA SHIGERU, YURIMOTO HISAYOSHI  日本天文学会年会講演予稿集  2006-  135  2006/08   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi  Denshi kenbikyo  41-  (2)  134  -137  2006/07   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi  Planetary People  15-  (2)  43  2006/06   [Not refereed] [Not invited]
  • 圦本 尚義  学術月報  59-  (3)  173  -178  2006/03   [Not refereed] [Not invited]
  • YURIMOTO HISAYOSHI  日本地球化学会年会講演要旨集  53rd-  265  2006   [Not refereed] [Not invited]
  • Kuramoto Kiyoshi, Yurimoto Hisayoshi  Planetary People  14-  (4)  193  -200  2005/12   [Not refereed] [Not invited]
  • TOMEOKA Kazushige, TSUCHIYAMA Akira, YURIMOTO Hisayoshi  Journal of the Mineralogical Society of Japan  34-  (3)  96  -97  2005/05   [Not refereed] [Not invited]
  • LITASOV Konstantin, YURIMOTO Hisayoshi, LITASOV Yury, RASSKAZOV Sergey, MALKOVETS Vladimir, TANIGUCHI Hiromitsu  Northeast Asian studies  9-  159  -178  2005/03   [Not refereed] [Not invited]  
    Trace element chemistry of clinopyroxene in the mantle xenoliths from melanephelinites of the Burkal volcanic group has been studied. The Burkal group is composed of several local outcrops of 5-8 Ma melanephelinites within the Khentey domal uplift near the Russia/Mongolia boundary. Cr-diopside group xenoliths include garnet and spinel lherzolite, spinel harzburgite and dunite, and garnet and spinel pyroxenites. Hydrous minerals were not detected, however shallow mantle feldspatic metasomatism is present. Clinopyroxene from garnet lherzolites has high TiO_2, Al_2O_3, and Na_2O relative to clinopyroxene from spinel lherzolites. Olivine has composition of Fo_<90-92>. Spinel has Mg#=60-80 and contains 10-46 wt.% Cr_2O_3. Clinopyroxene from garnet lherzolites has REE patterns typical for fertile peridotites. Trace element patterns of clinopyroxene from depleted spinel peridotites show progressive depletion in HREE and HFSE and enrichment in LREE toward more depleted varieties of harzburgites and dunites. REE patterns of clinopyroxene in harzburgites are strongly U-shaped and have (La/Sm)n=5-36 and (Sm/Yb)n=0.4-2.1. Clinopyroxene in harzburgites has also extremely low Zr content (0.4-3.4ppm) and high Ti/Zr ratio ranged in 190-240. The patterns of clinopyroxene in depleted peridotites are indicative of significant partial melting (up to 15-20%) of the primary substrate followed by cryptic metasomatic enrichment by silicate or carbonatitic melt. Estimation of T-P parameters for garnet lherzolites reveals equilibration at 17-23 kbar (60-90km depths) and 1050-1150℃. T-estimations for harzburgites and dunites indicate, that they may form veins at 50-70km depth, whereas shallow mantle (low-T) depleted peridotites were not detected. The uppermost mantle may be composed of fertile spinel lherzolites.
  • Yohei Shimizu, Shoji Arai, Tomoaki Morishita, Hisayoshi Yurimoto, Fernando Gervilla  Special Paper of the Geological Society of America  389-  265  -276  2004/12   [Not refereed] [Not invited]  
    Felsic and related veins within mantle-derived peridotite xenoliths from Tallante, Spain, were examined in order to understand the mantle-wedge processes related to the behaviour of Si-rich melt. The thickest part of the vein has a quartz diorite lithology, and is composed mainly of quartz and plagioclase, with pyroxenes, hydrous mineral, apatite, zircon and rutile present as minor phases. The thinner parts are free of quartz and predominantly composed of plagioclase. Orthopyroxene always intervenes between the internal part (plagioclase ± quartz) and host peridotite, indicating that it is a product of interaction between silica-oversaturated melt and olivine. This indicates that a sufficiently high melt/wall rock ratio enabled the melt to retain its silica-oversaturated character. The quartz diorite part has adakite-like geochemical signatures, except for negative Ba, Rb Eu and Sr anomalies, and positive Th and U anomalies. These negative anomalies indicate that fractionation of plagioclase and hydrous minerals was achieved between the upper most mantle and the slab melting zone. The shape of the rare-earth element (REE) pattern of clinopyroxene in quartz diorite is strikingly similar to that of clinopyroxene phenocrysts from Aleutian adakites. However, the former has one order higher REE contents than the latter, except for Eu which shows a prominent negative spike. This feature was caused by the precipitation of large amounts of plagioclase and small amounts of clinopyroxene from a fractionated adakitic melt before and during solidification. This adakitic melt was produced by partial melting of a detached and sinking slab beneath the Betic area in the Tertiary.
  • TOMEOKA K., TSUCHIYAMA A., YURIMOTO H.  日本鉱物学会・学術講演会,日本岩石鉱物鉱床学会学術講演会講演要旨集  2004-  2004/09   [Not refereed] [Not invited]
  • SHIMOJUKU Akira, KUBO Tomoaki, OHTANI Eiji, YURIMOTO Hisayoshi  Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences  2004-  2004/09   [Not refereed] [Not invited]  
    Diffusion experiments of mantle minerals are important for understanding the rheological properties of the Earth's mantle and subducting slab, because the atomic diffusion in the crystals controls plastic deformation in silicate minerals. Wadsleyite is a major constituent mineral in the mantle transition zone. Hence experimental examination of the diffusion rates is essential for debating the rheology of mantle transition zone. In this study, Si self-diffusion rates in wadsleyite were measured at 18 GPa, 1703-1903 K and the viscosity of wadsleyite deformed by diffusion creep was calculated. Our results imply some portions in cold subducting slabs, where the grain size reduces to less than 1 micron after the olivine-spinel transformation, become weaker than the surrounding mantle.
  • Tomeoka Kazushige, Tsuchiyama Akira, Yurimoto Hisayoshi  Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences  2004-  (0)  146  -146  2004   [Not refereed] [Not invited]  
     太陽系始原物質とは,コンドライト隕石に代表される太陽系で最も始原的な物質であり,「45.6億年前の太陽系の始まり」を我々に直接伝えてくれるロゼッタストーンだと言えよう。これまでの膨大な始原物質研究の成果は,現在の太陽系の起源・進化のモデルの構築に大きな役割を果たしてきた。いまや物質科学は惑星科学を支える重要な一分野である。今回のシンポジウムでは,始原物質科学の最前線で活躍しておられる研究者の方々をお招きし,ご自分の研究を紹介していいただく。このシンポジウムの目的は,普段,惑星科学とは直接関係の薄い鉱物科学者たち(とくに若い人たち)に太陽系始原物質科学の最前線に触れていただき,その面白さ,意義を知っていただくことである。そして,私たちは,願わくは鉱物科学者と惑星科学者がお互いの接点を見出し,新たな研究テーマを創出するきっかけがつくれればいいと思っている。
  • Itoh Shoichi, Russell Sara, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  169  -169  2004   [Not refereed] [Not invited]  
    Amoeboid olivine aggregates (AOAs) are major types of refractory objects in carbonaceous chondrites (CC). However, AOAs from ordinary chondrites (OC) have not been reported, even though fine-grained CAIs from OC have been found. Here we report the petrography and isotopic compositions of AOAs from the Semarkona LL3.0 chondrite, in order to compare the petrography and isotopes of AOAs in OC and CC, and establish the genetic relationships between CAIs and AOAs in the early solar system.
  • Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  17  -17  2004   [Not refereed] [Not invited]  
    惑星固体物質の成因は化学組成の変化を用いた元素組織学により主に議論されてきた。最近のその場局所同位体分析は同位体による組織学を構築できるレベルにまで進歩しつつある。そもそも同位体組織と元素組織は整合的であるべきだが,太陽系最古の物質といわれるCAIにおいて元素組織学による成因と同位体組織学による成因が甚だしい不一致を示すことが少なくない。本発表では固体物質の成因の完全理解のためにすべての元素とその同位体の分析と解析をどのように活用すべきか,その指針を論じたい。
  • Yoshitake Miwa, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  170  -170  2004   [Not refereed] [Not invited]  
      CHコンドライトに分類されるAcfer 214中のコンドリュールの酸素同位体組成を,マルチコレクター付随型二次イオン質量分析計(東京工業大学)を用いて高精度分析を行った。 その結果,Acfer 214中のコンドリュールはAllende隕石のコンドリュールの酸素同位体を内包し、重い同位体側に広がっているということがわかった。 このことより、CHコンドライトはCVコンドライトより多様性のある環境下で形成されたコンドリュールを集積していることを示す。
  • Nagashima Kazuhide, Krot Alexander, Sara Russell, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  171  -171  2004   [Not refereed] [Not invited]  
    我々は,イオンビームなど荷電粒子に感度がある二次元半導体素子SCAPSを開発してきた。今回,SCAPSを投影型SIMSに装着した顕微同位体分析法により始源的コンドライトのマトリックス物質の同位体分布を二次元的にサーベイした.その結果,始源的コンドライト中には太陽系の材料となった星くず(プレソーラー粒子)が,わずかであるが,生き残っていることが判明した.講演では,種々のコンドライトにおけるプレソーラー粒子の存在度の評価結果を報告する.
  • Kobayashi Sachio, Tonotani Azusa, Nagashima Kazuhide, Krot Alexander N., Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  172  -172  2004   [Not refereed] [Not invited]  
     プレソーラー粒子は太陽系とは大きく異なる同位体組成により同定される.本研究では始源的な隕石であるCOコンドライトYamato81025とALHA77307の薄片から,その場同位体面分析によりプレソーラー粒子の同定を目指した.プレソーラー粒子の発見には東京工業大学の同位体顕微鏡システムを用いた.発見した粒子はSEM-EDSを用いて組織と化学組成を決定した. 発表では,同定した個々のプレソーラー粒子についてと,異なる隕石間における存在度の違いについて議論する.
  • Makide Kentaro, Kobayashi Sachio, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  51-  (0)  249  -249  2004   [Not refereed] [Not invited]  
    Acfer214中の酸素同位体組成は、個々のCAI中で均一であるが、異なるCAI間に16O-richから16O-poorに至る約50‰の巾に分布している(Kobayashi et.al,2003)。本研究は26Alの存在と酸素同位体組成の不均一の相関を明らかにするため、Acf214中の酸素同位体組成の異なる6つのCAIについて二次イオン質量分析計(Cameca ims-1270)を用いてAl-Mg年代測定を行った。結果すべてのCAIについて26Mgの過剰はなく、26Alの存在と酸素同位体異常の程度に相関はなかった。これらの結果は原始太陽系円盤進化に次のような制約を課す。(1)Al-Mgシステムが時計として働くのであれば、CAI形成は原始太陽系円盤において300万年以上継続しその間酸素同位体不均一が円盤内に残っていた。もしくは、(2) 26Alと酸素同位体の不均一が円盤内に存在してこの両者の分布は相関がなかった。
  • Litasov Konstantin, 圦本 尚義, Litasov Yury  Northeast Asian studies  (9)  159  -178  2004   [Not refereed] [Not invited]
  • Inoue Toru, Wada Tomoyuki, Sasaki Rumi, Irifune Tetsuo, Yurimoto Hisayoshi  Abstracts for Annual Meeting of the Mineralogical Society of Japan  2003-  (0)  15  -15  2003   [Not refereed] [Not invited]  
    (はじめに)
     水は地球表層に大量に存在する主要な揮発性成分の1つであり、その水がスラブの沈み込みによって常に地球内部に供給され、鉱物の物性や溶融温度に大きく影響を与えることが明らかにされてきている。特にマントルの主要構成鉱物はカンラン石であり、その高圧相のwadsleyite, ringwooditeには3wt%ものH2Oが結晶構造中に含まれうることが明らかにされてきてはいるが、実際の水の存在割合を議論する場合、それらの鉱物間の水の分配が重要で、マントル中のどの層に相対的にどれぐらい水が存在可能かということを知る必要がある。現在までolivine-wadsleyite間(Chen et al.,2003)、及びwadsleyite-ringwoodite間(Kawamoto et al., 1996)でこのようなデータが報告されているが、特に後者ではデータは1点だけである。本研究ではオリビンの高圧相転移のwadsleyite-ringwoodite、及びringwoodite-perovskite間における水の分配を明らかにし、上部マントル、マントル遷移層、及び下部マントル間の水の分配を明らかにした。
    (実験方法)
     本研究の含水系の出発物質には(Mg0.8Fe0.2)2SiO4+16wt%H2OになるようにFe2SiO4, Mg(OH)2, SiO2の混合粉末試料を、無水系には(Mg0.8Fe0.2)2SiO4になるようにFe2SiO4, MgO, SiO2の混合粉末試料を用意した。実験装置は愛媛大学設置のマルチアンビル型高圧発生装置を使用し、wadsleyite-ringwoodite間の水の分配を求める実験は14.6~17.0GPa、1400℃の条件下で、ringwoodite-perovskiteの水の分配を求める実験は~23.5GPa、1600℃の条件下で行った。今回の実験は含水量測定に耐え得る大きな共存結晶を得ることを目的としているので、比較的大きい含水量を選択し、また温度も含水ソリダス直上になるよう設定した。実験は目的の圧力まで加圧、圧力を一定に保ちながら加熱した後、急冷減圧し回収した。回収試料は顕微ラマン分光装置、及び反射電子像により相の同定を、さらにエネルギー分散型電子顕微鏡により化学組成を測定した。また含水量は東京工業大学設置の二次イオン質量分析計により測定した。
    (実験結果)
     含水系で含水量測定に耐え得る50μm以上のwadsleyite及びringwooditeの共存結晶、及びringwoodite及びperovskiteの共存結晶を合成することに成功し、この共存結晶間での水の分配が明らかにできた。Wadsleyiteとringwoodite間の水の分配係数は5点で制約できたが約2程度となり、これはKawamoto et al.(1996)での値(2.5)と近い値を示した。またringwooditeとperovskite間の水の分配係数は約10かそれ以上となった。我々の以前の研究(Chen et al.,2003)によりwadsleyiteとolivine間の水の分配係数は約5程度と明らかにされているので、410km以浅の上部マントル、410-520km及び520-660km間のマントル遷移層、及び660km以深の下部マントル間での水の分配は4:20:10:1ということになる。すなわち、マントル遷移層に極めて高濃度に水が保持され、地球内部の水の貯蔵庫となっていることが考えられる。
  • Kubo Tomoaki, Shimojuku Akira, Ohtani Eiji, Yurimoto Hisayoshi  Abstracts for Annual Meeting of the Mineralogical Society of Japan  2003-  (0)  29  -29  2003   [Not refereed] [Not invited]  
    オリビンの高圧相であるwadsleyiteは,地球内部のマントル遷移層における主要構成鉱物であり,wadsleyite中の原子の拡散速度を測定することは,マントル遷移層のレオロジーやダイナミクス,電気伝導度を議論するうえで重要である。本研究では15-18.5GPa, 1473-1973Kにおいてwadsleyite中のMg-Feの相互拡散実験を無水と含水条件下で、またSiの自己拡散実験を無水条件下で行った。それらの結果からマントル遷移層の含水量と電気伝導度,およびマントル遷移層のレオロジーに関して考察を行う。
     高圧実験は東北大学理学部設置の3000 ton 川井型高圧発生装置(MAP-3000)を用いて行った。Mg-Fe相互拡散実験では、Mg#90とMg#100のwadsleyite多結晶体を接合し、酸素分圧はNi-NiOバッファーで制御しながら実験を行った。FTIR測定により、無水条件下では0.01 wt.%以下、含水条件下では0.02-0.23 wt. %のH2Oがwadsleyite多結晶体中に含まれていることがわかった。拡散実験後, EPMAを用いて拡散プロファイルを測定し拡散係数を算出した。wadsleyite中のMg-Fe相互拡散には組成依存性があり,Boltzmann-Matanoの解析法を用いて拡散係数を求めた結果,Fe 成分が多いほど拡散速度は速くなることがわかった。無水条件下ではMg-Fe相互拡散の活性化エネルギーは156kJ/molと求められた。16 GPa, 1200 °C における wadsleyite中のMg-Fe 相互拡散係数は,無水条件下で1.85×10-14 m2/s, 含水条件下で5.53×10-13 m2/s と求められた. wadsleyite中のMg-Fe 相互拡散係数は,0.02-0.23 wt. %のH2Oの存在下で約3倍速くなる。また含水量が多いwadsleyiteについては,粒界拡散の寄与も認められた。Schultz et al. (1993) による地球内部の電気伝導度観測とMg-Fe相互拡散係数から計算した電気伝導度を比較した場合,マントル遷移層には約0.2 wt. %程度のH2Oが存在する可能性がある。
     Si自己拡散実験では、出発物質としてwadsleyite多結晶体表面に拡散源となる29Siに富んだSiO2を蒸着したものを用いた。拡散実験後,東京工業大学設置の二次イオン質量分析計(SIMS)によるDepth profile法を用いて29Siの拡散プロファイルを作成し,拡散係数を算出した。拡散プロファイルは粒内拡散と粒界拡散が寄与している二つの領域からなる。粒内拡散が寄与している領域について薄膜状拡散源に対する解法をもちいて粒内拡散係数(Dv)を求め、粒界拡散が寄与している領域についてはLe Claire(1963)による解法を用いて粒界拡散係数(_Dgb)を求めた。Si自己拡散の活性化エネルギーは、粒内拡散の場合273kJ/mol、粒界拡散の場合254kJ/mol と推定された。Wadsleyite中のSiの拡散速度は,Mg-Feの相互拡散速度と比較して約6桁遅い。また,Dohmen et al. (2002) によるオリビン中のSiの拡散速度よりも1桁程度高くYamazaki et al. (2000) によるペロブスカイト中のSiの拡散速度と同程度であった。得られた拡散係数を用いてwadsleyiteが拡散クリープによって変形した際の粘性率を計算した。また,転位クリープによって変形した際の粘性率をKarato et al. (2001) によるクリープパラメーターを用いて計算した。それらの結果と地球物理学的観測による粘性値を比較して,マントル遷移層では拡散クリープおよび転位クリープの両方の変形メカニズムが卓越する可能性がある。また沈み込むスラブの低温条件では拡散クリープが卓越していることが予想され,この場合は相転移に伴う結晶粒径の細粒化によってプレートが軟化する可能性がある。
  • SHIMIZU Yohei, Arai Shoji, Yurimoto Hisayoshi, Gervilla Fernando  Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists  2003-  (0)  80  -80  2003   [Not refereed] [Not invited]  
    (はじめに)
    斜長石かんらん岩は地殻の薄く地温勾配の高い海洋底マントルにおいて一般に存在すると考えられている。海洋底から得られるかんらん岩中の斜長石の起源については、サブソリダス下での反応ではなく、トラップメルトからの晶出が大半であるらしい(Dick, 1989) 。南東スペイン、タジャンテにおけるかんらん岩捕獲岩にも斜長石かんらん岩が存在する。本発表では、タジャンテのかんらん岩における斜長石かんらん岩の起源について議論する。
    (かんらん岩について)
    スペイン南東部タジャンテ周辺域には中新世にカルクアルカリ火山活動が、それに引き続き鮮新世にマントル捕獲岩を包有したアルカリ玄武岩が噴出した。超苦鉄質捕獲岩類は、Frey and Prinz (1978)でいうところの、Group I(レールゾライトからハルツバージャイト)と、母岩と同じマグマソースを持つとGroup II(クライノパイロクシナイト)に分けられる。これらの岩石は複合捕獲岩(Irvine, 1975)を形成することがある。Group Iの岩石は鉱物組み合わせにより、スピネルかんらん岩と斜長石かんらん岩の2つに分類される。Group Iにはしばしば斜方輝石-斜長石脈が観察され、最も太い脈では石英を伴い、その起源としてはスラブ起源のSiに富むメルトが考えられている(Arai et al. 2003)。Group IIと複合捕獲岩を形成するGroup Iの岩石、または斜方輝石-斜長石脈を含む岩石では斜長石が多く観察されるが、それらと無関係の独立した捕獲岩でも斜長石が見出される。
    (鉱物化学組成について)
    かんらん石のFo値とスピネルのCr#(=Cr/(Cr+Al)原子比)の関係において、スピネル、斜長石かんらん岩とほぼ同じスピネルCr#(0.15-0.22)をもつが,後者の方がより低いFo値をもつ(スピネルかんらん岩:Fo90.5-91、斜長石かんらん岩Fo89.8-90.8)。また、単斜輝石のAl2O3、Cr2O3量を比較するとスピネルかんらん岩は斜長石かんらん岩より高く,TiO2wt%は斜長石かんらん岩のほうが高い。東工大に設置されているSIMSにより求められた単斜輝石中の微量元素存在量のうち、La/Yb比はスピネルかんらん岩、斜長石かんらん岩はそれぞれ1.32-1.99、0.70-1.84であるのに対し、斜方輝石-斜長石脈を含むサンプルにおいては1.57-4.71と比較的高い値を示す。REEパターンにおいてはスピネル、斜長石かんらん岩は、後者がEuの負異常を持つ点を除いて、ほぼ似たいようなフラットなパターンを示すのに対し、脈を持つサンプルはLREEにエンリッチしたパターンを示す。
    (議論&まとめ)
    スピネルかんらん岩は圧力低下に伴い斜長石かんらん岩へとサブソリダス変化することが知られている(Kushiro and Yoder, 1966)。しかしながら、この反応は系のCr/Al比に影響を受け、Cr/Al比が高い岩石ほどこの反応曲線はより低圧側へと移動することが知られている。一連の様々な枯渇度を有するスピネルかんらん岩が減圧した後、高枯渇度の部分はそのままで、低枯渇度の部分にのみ斜長石が形成されることが起こり得る。タジャンテでは一見これが起きているように思える。そのことは微量元素の検討からも指示され、スピネル、斜長石かんらん岩はほぼ同じようなREEパターン、La/Yb比を持つのに対し、外界からのメルトの影響を受けたサンプルはLREEにエンリッチしたパターンに変化したことが明瞭である。したがって、タジャンテの斜長石かんらん岩は外部からのメルトの侵入を受けて形成されたものではなく、サブソリダス変化によってもたらされたと結論づけられる。
  • Nagashima Kazuhide, Takeda Yutaka, Itoh Shoichi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  50-  (0)  37  -37  2003   [Not refereed] [Not invited]  
    CRコンドライトのMg-richコンドルールのコアおよび,リムの酸素同位体分布について報告する.リムの酸素同位体組成分布は,同位体マッピングを行うことで評価した.その結果,およそ半分のオリビン粒子が16Oに富む組成をもち,その他の半分のオリビンや他の粒子は16Oに乏しい組成を持つことが分かった.16Oに富むオリビンの存在は,コンドルールリムは,起源の異なる物質が,コンドルールに集積することによって形成されたことを示唆する.
  • Itoh Shoichi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  50-  (0)  38  -38  2003   [Not refereed] [Not invited]  
    Y81020 CO3.0 chondriteからO-16-poorなコンドルールを内包するO-16-richなigneous CAIを発見した。さらに、O-16-poorなmelilite coreをO-16-richなigneous CAIが取り囲んでいた。結果、コンドルールとCAIの形成は空間的、時間的に重なっていたことを示した。酸素同位体の結果からから、初期太陽系における固体物質は循環しながら進化したことを示した。
  • Matsunami Yoshiyuki, Nagashima Kazuhide, Nagasawa Hiroshi, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  50-  (0)  39  -39  2003   [Not refereed] [Not invited]  
     炭素質隕石を初めとする始源的隕石は太陽系初期に形成された。これら隕石中には太陽系形成以前に存在した恒星の放出物から形成された微粒子が太陽系形成時の加熱による蒸発,溶融をのがれ,それら隕石中にごく少量含まれている.これらは一般にプレソーラーグレインとよばれる。 従来プレソーラーグレインの分離回収にはシカゴ大学のグループが開発した酸を用いて隕石を分解する方法が広く用いられている(Amari et al., 1994).シカゴグループの方法はシリケイト成分をフッ酸を用いて除去し,その残査からプレソーラーグレインを見つけ出す方法である.現在までに報告されているプレソーラーグレインのほとんどがこの方法で分離,回収された物である.本研究ではNaOHを用いた岩石融解法(Chan et al., 1983)を用いて炭素質コンドライト中のシリケイト成分を融解し,その残渣を同位体分析しプレソーラーグレインを分離する方法の開発を行った.異なった方法でシリケイト成分を除去することにより,今までの結果を独立に検証することができ,また新しい組成や形状のプレソーラーグレインを発見することが期待できる.
  • Abe Natsue, Arai Shoji, Matsukage Kyoko, (Tanaka)Ninomiya Chima, Shcheka Sergei, Yurimoto Hirayoshi  日本地質学会学術大会講演要旨  109-  (0)  2002/09   [Not refereed] [Not invited]
  • Takayanagi Isao, Nakamura Junichi, Fossum Eric R., Nagashima Kazuhide, Kunihiro Takuya, Yurimoto Hisayoshi  ITE Technical Report  26-  (26)  7  -12  2002/03   [Not refereed] [Not invited]  
    A stacked CMOS active pixel sensor (APS) with a newly devised pixel structure for charged particle detection was designed, fabricated and tested. Hot carrier generation at the readout transistor inside the pixel was suppressed, thereby low leakage current as low as 5×10^<-8> V/s at the pixel electrode under low operation temperature was achieved. Ion conversion characteristics were tested with the imager installed in a projection-type Secondary Ion Mass spectrometer (SIMS). Total noise floor and dynamic range were measured to be 3 ions and 84dB for 10keV incident Al ions, respectively.
  • Abe Natsue, Arai Shoji, Matsukage Kyoko, (Tanaka)Ninomiya Chima, Shcheka Sergei, Yurimoto Hirayoshi  Annual Meeting of the Geological Society of Japan  2002-  (0)  2002   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi, Kuramoto Kei  Abstracts of Annual Meeting of the Geochemical Society of Japan  49-  (0)  112  -112  2002   [Not refereed] [Not invited]  
    隕石中の酸素同位体異常の存在から, 原始太陽系星雲中には酸素同位体異常が存在していたことは広く知られているが, その起源については未だに謎である。今回, 分子雲が原始惑星系円盤に進化したとき, 分子雲で発生していた非質量依存性の酸素同位体分別がどのような変化をするのか考察した。その結果, 同位体異常は原始惑星系円盤内部領域において普遍的に起こる現象かもしれないという結果を得た。
  • Nagashima Kazuhide, Itoh Shoichi, Kunihiro Takuya, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  49-  (0)  111  -111  2002   [Not refereed] [Not invited]  
    同位体顕微鏡による酸素同位体分布マップとEPMAによる元素分布マップを比較することにより南極産炭素質隕石Y81020 (CO3.0)中に見つかった粗粒CAIの鉱物内の同位体不均一が鉱物の結晶成長に伴いどのようにして導入されたのかが議論された。酸素同位体以上は単一プロセスでCAI中に記録されたのではなく、非平衡状態における鉱物の溶融と結晶成長によるものであった。
  • Itoh Shoichi, Nagashima Kazuhide, Kunihiro Takuya, Yurimoto Hisayoshi  Abstracts of Annual Meeting of the Geochemical Society of Japan  49-  (0)  110  -110  2002   [Not refereed] [Not invited]  
    南極産炭素質隕石Y81020 (CO3.0)中に見つかった粗粒CAIは内部がメリライトとファッサイトからなりWork-Loveringリムに囲まれている。このCAIを同位体顕微鏡を用いて空間分解能2ミクロンの酸素同位体分布マップを得ることに成功した。本発表ではその分析装置と分析法を示し、その結果の信頼性を吟味する。
  • ITO Motoo, YURIMOTO Hisayoshi  J. Geogr.  109-  (6)  836  -844  2000/12   [Not refereed] [Not invited]  
    Petrography or observation of petrographic texture is one of the most basic techniques for microanalysis of natural samples. Secondary ion mass spectrometry (SIMS) has been applied to isotope and trace element analyses in micron-size minerals in various natural samples evaluated by conventional petrography, e.g., search for the oldest rock, mineral and life, and for presolar grains. However, elemental texture and isotopic texture often indicate a different evidence of origin and evolution of the sample. In this paper, we reviewed SIMS history in cosmo-and geo-chemistry from a viewpoint from point-analysis to area-analysis. Here we propose that promotion of isotopic texture research, isotopography, is an important future trend of cosmo-and geo-chemistry. We also propose that further diffusion study in minerals under various Pressure-Temperature conditions is necessary. The analysis of isotopography by diffusion gives a quantitative scale of geospeedmetry of natural samples.
  • 国広 卓也, 永島 一秀, 高柳 功, 中村 淳一, 小坂 光二, 圦本 尚義  Abstracts Fall Meeting of the Japanese Society for Planetary Sciences  2000-  2000/10   [Not refereed] [Not invited]
  • Nagashima K, Tsukamoto K., Kobatake H., Satoh H., Yurimoto H.  Journal of the Japanese Association of Crystal Growth  27-  (1)  2000/07   [Not refereed] [Not invited]
  • Kobatake Hidekazu, Tsukamoto Katsuo, Nagashima Ken, Yokoyama Etsuro, Yurimoto Naoyosi, Satoh Hisao  Journal of the Japanese Association of Crystal Growth  27-  (1)  2000/07   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi  The Astronomical herald  93-  (3)  121  -133  2000/02   [Not refereed] [Not invited]
  • Nagashima K., Kunihiro T., Takayanagi I., Nakamura J., Kosaka K., Yurimoto H.  ITE Technical Report  24-  (3)  13  -18  2000/01   [Not refereed] [Not invited]  
    Output characteristics of two-dimensional solid-state detector for charged particles has been analyzed by ion irradiation with keV level energy. The detector was designed by CMOS rule and constructed as stacked CMOS-device[1]. The detector was operated under nondestructive readout mode due to correction of fixed pattern noises among pixels and reset noise of a pixel. The output signals of a pixel correlated linearly with incoming ions over the range of four orders of magnitude. Non-linear effects of the output is about 10% over the whole dynamic range of a pixel. The dominant effects of the non-linear components are reset voltage drop down by overlap capacitance. After correction of the drop down effect the nonlinearity reduced to percent level, the percent level nonlinearity was due to voltage dependence of pixel capacitance with ion irradiation.
  • ITO Motoo, YURIMOTO Hisayoshi  Journal of Geography (Chigaku Zasshi)  109-  (6)  Plate5a  -Plate5a  2000   [Not refereed] [Not invited]
  • N. Abe, M. Takami, H. Yurimoto  Ofioliti  24-  47  1999/12   [Not refereed] [Not invited]  
    There are some localities of residual peridotite xenoliths from western edge arcs of the Circum-Pacific Ocean. Abe (1997) and Abe et al. (1998; 1999) show that the peridotite xenoliths from those arcs underwent wedge mantle metasomatism with some influx from subducted slab. We report the petrological and geochemical characteristics of the ultramafic xenoliths in the Cenozoic alkali-olivine basalts of Oki-Dogo island, another locality reported by Abe (1997) and Abe et al. (1998; 1999) in the Japan Sea. Both Group I and II ultramafic xenoliths (classification by Frey and Prinz (1978), equivalent to Wilshire and Shervais (1975) Cr-diopside and Al-augite series, respectively) come from Oki-Dogo island. Preliminary data on the petrology of the ultramafite, and also mafic xenoliths are in Yamaguchi (1964), Aoki (1977) and Takahashi (1978). We present here their mineral chemistry, especially the abundance of trace-elements in clinopyroxenes of Group I peridotite and the metasomatism by Group II ultramafic xenoliths suite. Oki-Dogo Island is located at the northern end of the Southwest Honshu Arc in the Japan Sea. Extensive alkalic volcanism (mugearite, hawaiite, trachy-andesite, trachyte and alkali rhyolite) took place from late Miocene to early Pliocene in this island. Alkali-olivine basalts with a subordinate amount of basanites were extruded from many vents situated inside of the supposed magma chamber. These basalts were monogenetic in most cases and their extrusion started at least 3.6 Ma and lasted at least until 0.8 Ma (Kaneoka et al., 1977). Most of these alkali basalts are fresh and contain 2 to 15 percent normative nepheline. Ultramafic and mafic inclusions are commonly found in most of the monogenetic lava flows. According to Takahashi (1978), those xenoliths are classified into five groups: spinel lherzolite, banded spinel peridotite, banded plagioclase peridotite, gabbro and granulite groups. The rocks of the banded spinel peridotite group are cumulates formed by fractional crystallization of basic magmas in a pressure range between about 10 and 20 kb, and recrystallized at the same depth. Some of the spinel lherzolite group are cumulates from basic magmas in the upper mantle during the partial melting of the preexisting lherzolite. Group I peridotite, which was classified as spinel lherzolite group by Takahashi (1978), has very low-Cr spinel. The Cr (=Cr/(Cr+Al) atomic ratio) of chromian spinel is less than 0.3. Their Fo content of olivine varies from 90 to 83, while their NiO content is rather constant (0.25 to 0.40 wt%). Clinopyroxene grains in polished thin sections were analyzed in situ for abundances of REE, Ti, Sr, Y, Zr with the secondary ion mass spectrometer (SIMS; Cameca IMS-3f) at Tokyo Institute of Technology. The chondrite normalized REE patterns of clinopyroxene in Oki-Dogo Group I xenoliths are flat to U-shaped LREE-depleted. HREE contents, however, almost same level, which suggests that those peridotites have the same degree of melt extraction. The evidence from their REE patterns and trace-element contents suggest that the Group I peridotites underwent Fe-rich mantle metasomatism by the alkaline magma. The continental type mantle metasomatism as well as arc type metasomatism suggested by Abe (1997) occurs in mantle wedge.
  • TAKAYANAGI Isao, NAKAMURA Jun-ici, YURIMOTO Hisayoshi, KUNIHIRO Takuya, NAGASHIMA Kazuhide, KOSAKA Koji  電子情報通信学会技術研究報告. EID, 電子ディスプレイ  99-  (374)  7  -12  1999/10   [Not refereed] [Not invited]
  • Takayanagi Isao, Nakamura Jun-ici, Yurimoto Hisayoshi, Kunihiro Takuya, Nagashima Kazuhide, Kosaka Koji  IEICE technical report. Electronic information displays  99-  (374)  7  -12  1999/10   [Not refereed] [Not invited]  
    A stacked CMOS active pixel image sensor has been developed for detecting charge particles. Wide dynamic range of 80 dB and good linearity have been demonstrated with a charge particle imaging system which incorporates a secondary ion mass spectrometer (SIMS). Noise measurement results suggest that dynamic range exceeding 100 dB can be obtained if the reset noise is suppressed by utilizing the nondestructive readout (NDRO) capability of the CMOS APS.
  • Ueno Yuichiro, Isozaki Yukio, Maruyama Shigenori, Yurimoto Hisayoshi  日本地質学会学術大会講演要旨  106-  (0)  1999/10   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi  Journal of the Surface Science Society of Japan  20-  (9)  658  -664  1999/09   [Not refereed] [Not invited]
  • Yurimoto H., Kunihiro T., Nagashima K., Takayanagi I., Kosaka K.  ITE Technical Report  23-  (5)  19  -23  1999/01   [Not refereed] [Not invited]  
    Charged particles such as ion and electrons with keV order kinetic energy are important for probes and signals for surface analyses. Many detection systems have been developed for measurement of two-dimensional distribution for the particles. However, capabilities of solid-state area detector are not sufficient for quantitative analysis for the charged particles, although solid-state imager such as charge coupled device has been great succeeded to photon detection for optical spectroscopy. This paper discussed performance and characteristics of a novel solid-state imager for charged particles. This device is useful to charged particle detection such as mass spectrometry and electron microscopy.
  • Ueno Yuichiro, Isozaki Yukio, Maruyama Shigenori, Yurimoto Hisayoshi  Annual Meeting of the Geological Society of Japan  1999-  (0)  1999   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi  J. Surf. Sci. Soc. Jpn.  20-  (9)  658  -664  1999   [Not refereed] [Not invited]  
    Stratigraphy of oxygen isotope anomaly in Ca-Al-rich inclusions (CAIs) in primitive meteorites has been determined by secondary ion mass spectrometry. The results show that the CAIs have experienced multiple heating event in the protoplanetary disk as well as in vacuum. The oxygen isotope anomaly in CAIs was introduced by isotopic exchange reaction between the 16O-rich melt and the surrounding 16O-poor gas during the heating. A proposed energy source for the multiple heating would be flares of active protosun. The proto-CAIs generated near the protosun were launched into the meteorite forming region in the protoplanetary disk by bipolar out flow.
  • YURIMOTO Hisayoshi  Planetary People  7-  (1)  9  -10  1998/03   [Not refereed] [Not invited]
  • Ueno Yuichiro, Isozaki Yukio, Maruyama Shigenori, Yurimoto Hisayosi  Annual Meeting of the Geological Society of Japan  1998-  (0)  1998   [Not refereed] [Not invited]
  • Kunihiro Takuya, Nagashima Kazuhide, Kosaka Koji, Hirata Takafumi, Yurimoto Hisayoshi  Abstracts Fall Meeting of the Japanese Society for Planetary Sciences  1997-  1997/09   [Not refereed] [Not invited]
  • YURIMOTO Hisayoshi, MATSUMOTO Kazuya  Japan analyst  45-  (6)  493  -500  1996/06   [Not refereed] [Not invited]  
    Charged particles such as ions and electrons with keV order kinetic energy are important as probes and signals for surface analyses. Many detection systems have been developed to measure two-dimensional distribution of particles. However, the capabilities of solid-state area detector are not sufficient for quantitative analysis of the charged particles ; although the solid-state imager such as the charge coupled device has been successfully developed to detect photons in optical spectroscopy. This paper discusses the performance and characteristics of a novel solid-state imager for charged particles, which is useful for charged particle detection in such procedures as mass spectrometry and electron microscopy.
  • HIRATA Takafumi, YURIMOTO Hisayoshi  日本地質学会学術大会講演要旨  103-  (0)  1996/03   [Not refereed] [Not invited]
  • TSUNOGAE Toshiaki, YURIMOTO Hisayoshi  日本地質学会学術大会講演要旨  103-  (0)  1996/03   [Not refereed] [Not invited]
  • TSUNOGAE Toshiaki, YURIMOTO Hisayoshi  Annual Meeting of the Geological Society of Japan  1996-  (0)  1996   [Not refereed] [Not invited]
  • HIRATA Takafumi, YURIMOTO Hisayoshi  Annual Meeting of the Geological Society of Japan  1996-  (0)  1996   [Not refereed] [Not invited]
  • MIYAGI ISOJI, YURIMOTO Hisayoshi  Bulletin of the Volcanological Society of Japan  40-  (5)  349  -355  1995/10   [Not refereed] [Not invited]  
    Analytical method by secondary ion mass spectrometry, SIMS, is developed for water micro analysis of hydrous silicate glasses. Standard hydrous glasses are synthesized and carefully examined their homogeneities. "Matrix effect" for the determination of hydrogen analysis by the SIMS method is corrected using their SiO_2 content (wt. %). Using the SIMS, water contents of andesitic to rhyolitic glasses can be estimated precisely (≈±0.5wt. % H_2O). As an application of the SIMS analysis, water contents of melt inclusions and matrix glasses from the Aira eruptive products are examined. The water contents of the melt inclusions are 5-7 wt. % H_2O. This is consistent with the water contents calculated by the relationship between water solubility and water pressure from the data of Aramaki (1971).
  • ONO HIDEFUMI, HIROSE KEI, YURIMOTO HISAYOSHI, MARUYAMA SHIGENORI  Annual Meeting of the Geological Society of Japan  1995-  (0)  1995   [Not refereed] [Not invited]
  • Miyagi I., Yurimoto H., Takahashi E.  Programme and abstracts the Volcanological Society of Japan  1994-  (2)  1994/10   [Not refereed] [Not invited]
  • Wang Wu yi, Kurita Kei, Sueno Shigeho, Yurimoto Hisayoshi, Takahashi Eiichi  Programme and abstracts the Volcanological Society of Japan  1994-  (2)  1994/10   [Not refereed] [Not invited]
  • Tsunogae Toshiaki, Yurimoto Hisayoshi, Miyano Takashi  日本地質学会学術大会講演要旨  100-  (0)  1993/03   [Not refereed] [Not invited]
  • YORIMOTO Hisayoshi  ぶんせき  219-  190  -194  1993/03   [Not refereed] [Not invited]
  • KUROSAWA Masanori, YURIMOTO Hisayoshi, MATSUMOTO Kazuya  Japanese Magazine of Mineralogical and Petrological Sciences  22-  (2)  63  -68  1993   [Not refereed] [Not invited]  
    The abundance of hydrogen in olivines has been determined by secondaryion mass spectrometry (SIMS). Hydrogen implanted olivines were prepared for SIMSmeasurements as standards. A linear relationship was obtained between the relative hydrogen intensity ratio against the silicon and hydrogen concentrations overthe range of 100 to 25000 ppm H/Si.
  • Tsunogae Toshiaki, Yurimoto Hisayoshi, Miyano Takashi  Annual Meeting of the Geological Society of Japan  1992-  (0)  1992   [Not refereed] [Not invited]
  • Yurimoto Hisayoshi, Sueno Shigeho  X-RAYS  29-  (4)  259  -269  1987   [Not refereed] [Not invited]  
    Application of Secondary ion mass spectrometry (SIMS) to the study of chemical analyses of insulated materials is described. A simple working curve method is useful for the quantitative analyses of SIMS data. The sensivity acheaved is suffietient to concentration levels from ppm to ppb. This is demonstrated for the partition coefficients between olivine and magma and for the impuriry destribution in diamond thin film. A blieaf description of two demensional analyses is also made.

Awards & Honors

  • 2019/07   Meteoritical Society   Leonard Medal
      
    Winner: Hisayoshi Yurimoto
  • 2013   Miyake Award
      
    Winner: Hisayoshi Yurimoto
  • 2013   Geochemistry Fellow
      
    Winner: Hisayoshi Yurimoto
  • 2012   Meteoritical Society Fellow
      
    Winner: Hisayoshi Yurimoto
  • 2010   The Hokkaido Shimbun Culture Prize
      
    Winner: Hisayoshi Yurimoto
  • 2008   MICROCOPY Best Paper Award
      
    Winner: Hisayoshi Yurimoto
  • 2006   Mineralogical Society of Japan Award
      
    Winner: Hisayoshi Yurimoto
  • 2006   Geochemical Society of Japan Award
      
    Winner: Hisayoshi Yurimoto
  • 2004   Geochemical Journal Award
      
    Winner: Hisayoshi Yurimoto
  • 1998   Sakaki Award
      
    Winner: Hisayoshi Yurimoto
  • 1990   Mineralogical Society of Japan Encouragement Award
      
    Winner: Hisayoshi Yurimoto

Research Grants & Projects

  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(特別推進研究)
    Date (from‐to) : 2008 -2012 
    Author : Hisayoshi YURIMOTO
     
    北海道大学All types of primitive chondrites were analyzed isotopically insub-micrometer scale by isotope microscopy. Materials formed in pre-solar and early solar system agesare distinguished isotopically. The spatial distribution between the materials corresponds to formationsequences suggesting material evolution from presolar to early solar ages. Based on these results, wediscussed global and local characteristics of our solar system among planetary systems in the galaxy.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 2001 -2004 
    Author : Hisayoshi YURIMOTO
     
    東京工業大学It is believed that bulk chemical compositions among planets and asteroids in the solar system is similar but slightly different from the solar abundance ratios one another. The variations of the bulk composition may result from a global circulation of dusts around the proto-planetary disk. The dusts spiral into the proto-sun from outer edge of the disk and some of them launched from the inner edge of the disk to the outer-edge. In this study, we made chemical analyses of meteorites and numerical simulations of electro-magnetic effects, dynamic effects and chemical reaction network estimated in the proto-planetary disk. We may conclude the subjects as follows :1.Oxygen isotopic anomaly observed in the solar system was originated in the parent molecular cloud by a self-shielding effect of carbon monoxides by ultra-violet light irradiation.2.The oxygen isotopic fractionation in the molecular cloud was separated into interstellar gas and ice phases. Differences of dynamics and chemistry in the disk introduced the anomaly of oxygen isotopes in the solar system.3.oxygen isotopic compositions of planets were mainly determined by enrichment factor of dusts and evaporation of ice in a proto-planetary disk.4.A numerical simulation suggests that trajectory around a central star and the mass of gas planets were controlled by gas-dust ratios in a proto-planetary disk. The results correspond to probabilities of extra-solar planets by astronomical observations. This conclusion suggests that amounts of proto-planetary disk are determined by star-formation process, but the planetary formation around the star is controlled by the gas-dust ratio in the disk.5.Nature of electro-magneto vortex of interstellar plasma was simulated numerically. Inertia effects of electrons are important to the vortex evolution. Larger scale vortex is immediately fractionized to smaller scale ones. This process suggests that material mixing is promptly evolved in the space than ever thought.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 1998 -2000 
    Author : Hisayoshi YURIMOTO
     
    東京工業大学Recent development of microanalysis becomes applied to measure geochemical and chronological data from small particles and from grain boundary among minerals. Using these data, we can clarify evolution process of planetary materials at early solar system. Especially, micro-isotope analysis is the most powerful technique among them. Our earth science view is drastically changing by these techniques(Yurimoto, Kagaku 67, 1997). Among the micro-isotope measurement technique, secondary ion mass spectrometry(SIMS)is most impressive. However, present SIMS method is restricted to ion microprobe. Therefore, precise isotope-ratio imaging is difficult. In this study we develop new solid-state ion imager for SIMS.We demonstrate that the precision and spatial resolution of an ion microscope using SIMS coupled with a newly developed solid-state ion imager can be extended to two-dimensional isotope ratio imaging with permil precision. An isotopic map for oxygen clearly reveals the distribution of 4%-enrichment of 160 in spinel particles embedded in melilite from a Ca-Al-rich inclusion of a carbonaceous chondrite. This characterization technique thus provides the "eyes" to e small heterogeneity of isotope abundance in micro scale. It is likely to find broad application in earth, material, and life science research.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 1997 -1999 
    Author : Hisayoshi YURIMOTO
     
    東京工業大学Interstellar media in primitive meteorites are only clue to clarify presolar history. The difference between interstellar media and solar matters is only isotope ratio of elements. We have made in-situ measurements of isotope ratios, textures, shapes and crystal structures for individual fine particles in primitive meteorites. The goal of in this study is construction of new scenario for material evolution from interstellar media to planetary matters.A novel micro-scale analysis for oxygen isotope ratios has been developed by secondary ion mass spectrometry. A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions (-5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI.Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula. The 160-rich dust and 160-poor gas continued together in the solar nebula from the CAI-forming period until the chondrule-forming period.A possible scenario for new evidence would be an active protosun with bipolar out-flow. Interstellar media near the protosun has been processed thermally and then launched into outer solar system. Therefore, composition of solar nebulae distributed heterogeneously along radial direction, The characteristics of composition and isotope ratio of each planet have been achieved in the first million years of solar system evolution.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 1996 -1997 
    Author : Hisayoshi YURIMOTO
     
    東京工業大学We have been developing a new analytical method for precise U-Pb age determinations using an inductively coupled plasma mass spectrometry coupled with newly developed laser microprobe technique. In order to determine the precise U-Pb age data from 10 microns spot of the zircon samples, laser ablation sampling technique using 266nm UV laser beam was developed. Resultant sample volume for the analysis was decreased down to 1/50 level compared with conventional laser sampling technique using IR fundamental Nd-YAG laser, and therefore enhancement of elemental sensitivity of the mass spectrometer was inevitable for the U-Pb age determinations. In this study this was achieved by different three techniques ; (a) modification of ion extraction lens, (b) improving the vacuum for first ion extraction stage by applying the high capacity rotary pump, and (c) sensitive ion detection using 2 dimensional solid ion detector called AMI (Amplified MOS Imager). The basic isotopic data obtained here demonstrate clearly that U-Pb chronology using Laser-ICPMS has a potential to become a significant and cost-effective tool for use in U-Pb zircon chronology.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(試験研究(B))
    Date (from‐to) : 1994 -1995 
    Author : Hisayoshi YURIMOTO
     
    筑波大学->東京工業大学A novel solid-state area detector for charged particles has been developed in this study. The detector called AMI is based on semiconduct or theory for Si substrate. Pixel electrodes for bombardment of ions and electrons with the energy from eV to keV were deposited on the semiconductor device A prote-type model of isotope microscope has also been developed. The isotope microscope is combination system of the AMI detector with stigmatic secondary ion mass spectrometer.The isotope microscope applied to the study of isotope imaging of solid sample. Spatial resolution of the image achieved to 1 mum. The image size is 512 (H) x 250 (V) pixels. Dynamic range of one pixel is four orders of magnitude. The imaging area is controlled by zooming system of the mass spectrometer. The zooming area is over the range of 25 to 400 mum. We are planning to get isotope ratio image of meteoritic materials. The isotope image may make clear the origin and evolution of the solar system and planets. The AMI detector and isotope microscope are also effective tool for material sciences and high energy physics.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(一般研究(C))
    Date (from‐to) : 1991 -1992 
    Author : Hisayoshi YURIMOTO
     
    筑波大学Extra-solar materials in Ca, Al-rich inclusions (CAIs) from Allende meteorite have been investigated in this projects. The project may be summarized as follows:(1)Concentration mapping of CAI minerals has been generated by electron micro probe analyzer. The results show crystallization sequences of the minerals.(2)A novel negative-metal ion source (BLAKE-V) for secondary ion mass spectrometry (SIMS) was developed for precise oxygen isotope analyses of CAI minerals.(3)A precise oxygen isotope analysis in CAI minerals was developed using the Au^- primary beam from the BLAKE-V ion source.(4)Oxygen isotope distribution was homogeneous in intra-mineral in CAI, whereas was quite heterogeneous among minerals. Such relationship cannot be interpreted by chemical equilibrium among minerals.(5)The origin of CAI may be interpreted as follows: (a)Spinel grains in CAIs ware crystallized in super novae remnant. (b)pyroxene grains were generated in the mixing gas between the solar nebula and the remnant at the most outer rim of the solar nebulae. (c)In the solar nebulae super cooling liquid was precipitated, and melilite and anorthite grains were crystallized in the liquid.
  • Origin of the solar system
    Date (from‐to) : 1980

Educational Activities

Teaching Experience

  • Advanced Geochemistry
    開講年度 : 2017
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 地球化学,宇宙化学
  • Evolving Earth and Life
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 地球の形成,地球システム論,生命の起源,生物進化,絶滅,気候変動,古環境,物資循環,安定同位体
  • Earth's History
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 地球の形成,地球システム論,生命の起源,生物進化,絶滅,気候変動,古環境,物資循環,安定同位体
  • Basic Earth and Planetary Science Ⅱ
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 宇宙,惑星,大気と海洋の運動と構造,気候変動,地球環境
  • Introduction to Geochemistry
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 原子,分子,気体,固体,熱力学,液体,溶液


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