2024/03/24 更新

写真a

マキシマ アキオ
牧嶋 昭夫
MAKISHIMA Akio
所属
惑星物質研究所 教授
職名
教授
外部リンク

学位

  • 理学修士 ( 東京大学 )

  • 博士(理学) ( 東京大学 )

研究キーワード

  • Mass Sprctromrtry

  • analytical chemistry

  • geochemistry

  • 生体物質分析化学

  • 質量分析学

  • 分析化学

  • 地球科学

  • Metalomics

研究分野

  • ライフサイエンス / 人体病理学

  • 自然科学一般 / 宇宙惑星科学

  • ナノテク・材料 / 分析化学

  • 自然科学一般 / 固体地球科学

学歴

  • 東京大学    

    1984年4月 - 1986年3月

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    国名: 日本国

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  • 東京大学   Faculty of Science   Department of Chemistry

    1981年4月 - 1984年3月

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    国名: 日本国

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  • 東京大学    

    1993年1月

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経歴

  • 岡山大学 惑星物質研究所   教授

    2005年4月 - 現在

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    国名:日本国

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  • オックスフォード大学 地球惑星科学科   客員研究員

    1999年2月 - 2000年12月

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    国名:グレートブリテン・北アイルランド連合王国(英国)

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  • 岡山大学 固体地球研究センター   助教授

    1996年4月 - 2005年3月

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    国名:日本国

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  • 岡山大学 地球内部研究センター   助手

    1989年1月 - 1996年3月

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    国名:日本国

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  • 新日本製鐵(株)第一技術研究所   研究員

    1986年4月 - 1988年12月

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    国名:日本国

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所属学協会

  • アメリカ化学会

    2009年3月 - 現在

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委員歴

  • 岡山大学 自然科学研究科 地球物質科学専攻   専攻長  

    2007年4月 - 2013年9月   

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    団体区分:その他

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論文

  • Trace element and isotopic geochemistry of Cretaceous magmatism in NE Asia: Spatial zonation, temporal evolution, and tectonic controls 査読

    Petr L. Tikhomirov, Elena A. Kalinina, Takuya Moriguti, Akio Makishima, Katsura Kobayashi, Eizo Nakamura

    Lithos   264   453 - 471   2016年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Results of a comprehensive geochemical study (major and trace elements, and isotopes of Sr, Nd, Pb, Hf) of Cretaceous volcanic rocks from the Chukotka area in northeastern Russia are presented. Synthesis of available geological and geochronological data suggests diachronous onset of activity of the Okhotsk-Chukotka volcanic belt (OCVB), the largest magmatic province in the region. The OCVB consists of ca. 10(6) km(3) of volcanic rocks. At 106-105 Ma, subduction-related magmatism initiated in the southern and central segments of the OCVB. In the Central and Northern Chukotka areas, where the northern OCVB is exposed, onset of arc magmatism occurred ca. 10 m.y. after extension-related magmatism of the Chaun igneous province at 109-104 Ma. Mafic rocks from the OCVB yield (Sr-87/Sr-86)(80) (Ma) of 0.7033 to 0.7047, epsilon Nd-80 (Ma) of 0.0 to 7.10, epsilon Hf-80 (Ma) of 4.12 to 12.88, ((206)pw(204)pb)(80 Ma) of 18.11 to 18.42, and ((208)pb/(204)pb)(80 Ma) of 37.96 to 38.21. Volcanic rocks from the Chaun province, as well as OCVB rocks from Northern Chukotka, originate from a relatively enriched source and have (Sr-87/Sr-86)(80) (Ma) of 0.7088 to 0.7100, epsilon Nd-80 (Ma) of -5.81 to -3.42, epsilon Hf-80 (Ma) of -3.40 to -0.25, ((206)pb/(204)pb)(80 Ma) of 18.69 to 18.90, and ((208)pb/(204)pb)(80 Ma) of 38.65 to 38.86. No definitive across-arc elemental or isotopic zonation of the OCVB has been revealed, probably because of wide-scale crustal melting and subsequent contamination of mantle-derived melts. However, there is a clear along-arc isotopic zonation. In our interpretation, this results from heterogeneity of the subcontinental lithospheric mantle, which likely was a major contributor to the magma source. The similar isotopic signatures of silicic (dominantly crust-derived) and mafic (mantle-derived) volcanic rocks in each OCVB segment imply that remelting of juvenile mafic underplated material was the main process responsible for the crust-derived magma generation. These data from the major Cretaceous magmatic provinces of northeast Asia are synthesized in context of existing plate tectonic reconstructions. (C) 2016 Elsevier B.V. All rights reserved:

    DOI: 10.1016/j.lithos.2016.08.009

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  • Cu purification using an extraction resin and Cu(I) for isotope ratio determination by MC-ICP-MS. 査読

    Makishima, A

    chromatography   1   96 - 107   2014年

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    担当区分:筆頭著者  

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  • Low-blank chemistry for Zn stable isotope ratio determination using extraction chromatographic resin and double spike-multiple collector-ICP-MS 査読

    Akio Makishima, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   28 ( 1 )   127 - 133   2013年1月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ROYAL SOC CHEMISTRY  

    A new low-blank Zn separation method employing an extraction chromatographic resin using Aliquat 336 (commercially available as TEVA resin) has been developed for Zn isotope composition determination by double spike-multiple collector-ICP-MS. The silicate sample solution containing 0.1 mu g Zn in 0.5 mol L-1 HBr containing 0.15% ascorbic acid (AA) is passed through a 1 mL column with 0.33 mL TEVA resin. While Zn is absorbed, major elements are eluted with 0.5 mol L-1 HBr with AA. Afterwards, Zn was recovered with 2 mol L-1 HNO3. Recovery yield using silicate samples was 96.7 +/- 6.8% (n = 10) and total blank was 0.05 ng (n = 6). The blank level is from 1/300 to 1/20 of previous studies, meaning 0.1 mu g of Zn is sufficient for analysis. The Zn-67-Zn-70 double spike method was used in MC-ICP-MS. delta Zn-66 of three USGS standard silicate reference materials (BHVO-1, AGV-1 and PCC-1) and seven GSJ silicate reference materials (JB-1, -2, -3, JA-1, -2, -3 and JP-1) were determined. Reproducibility of (delta Zn-66 of the total silicates was 0.19%, (2SD). delta Zn-66 of three carbonaceous chondrites (Orgueil, Murchison and Allende) were also determined and compared with those of references.

    DOI: 10.1039/c2ja30271c

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  • A simple and fast separation method of Fe employing extraction resin for isotope ratio determination by multicollector ICP-MS. 査読

    Makishima, A

    International Journal of Mass Spectrometry and Chromatography   1   195 - 203   2013年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • 「はやぶさ」回収試料初期分析に至るまで : 地球惑星物質総合解析システムの構築 招待 査読

    中村 栄三, 牧嶋 昭夫, 森口 拓弥, 小林 桂, 田中 亮吏, 国広 卓也, 辻森 樹

    表面科学 : hyomen kagaku = Journal of the Surface Science Society of Japan   33 ( 12 )   681 - 686   2012年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:日本表面科学会  

    DOI: 10.1380/jsssj.33.681

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  • High-resolution MC-ICPMS employing amplifiers with a 10 12 ohm resistor for bulk sulfur determination in biological and geological samples 査読

    Akio Makishima, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   27 ( 5 )   891 - 895   2012年5月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    The analytical performance of high-resolution multiple-collector inductively coupled plasma mass spectrometry (HR-MC-ICPMS), employing amplifiers with a 10(12) ohm resistor, was examined. HR-MC-ICPMS showed 50 times higher detection efficiency and 100 times better precision for sulfur and S-34/S-32 than the single-collector high-resolution sector field type ICPMS (HR-ICP-SFMS). The 3 sigma detection limits for S-32 and S-34 were 0.2 and 6 ng mL(-1), respectively. No matrix effects were observed, for up to 3000 mu g g(-1) of total dissolved solids (TDS), within 0.6% error. Thus when the isotope dilution (ID) technique is utilized, this method allows analyses of sulfur concentration of seven times smaller, with six times better precision, than the HR-ICP-SFMS methods. To demonstrate the applicability of this ID-HR-MC-ICPMS method, bulk sulfur concentrations in bovine serum albumin, human serum, eight silicate reference materials (JB-2, JB-3, JA-2, JA-3, JP-1, BCR-2, BHVO-1 and AGV-1), and four carbonaceous chondrites (Murchison, Allende, Dal al Gani 521 and 194) were measured.

    DOI: 10.1039/c2ja10337k

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  • The Cretaceous Okhotsk-Chukotka Volcanic Belt (NE Russia): Geology, geochronology, magma output rates, and implications on the genesis of silicic LIPs 査読

    P. L. Tikhomirov, E. A. Kalinina, T. Moriguti, A. Makishima, K. Kobayashi, Yu I. Cherepanova, E. Nakamura

    Journal of Volcanology and Geothermal Research   221-222   14 - 32   2012年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Cretaceous Okhotsk-Chukotka volcanic belt (OCVB) is a prominent subduction-related magmatic province, having the remarkably high proportion of silicic rocks (ca. 53% of the present-day crop area, and presumably over 70% of the total volcanic volume). Its estimated total extrusive volume ranges between 5.5×10 5km 3 (the most conservative estimate) and over 10 6km 3. This article presents a brief outline of the geology of OCVB, yet poorly described in international scientific literature, and results of a geochronological study on the northern part of the volcanic belt. On the base of new and published U-Pb and 40Ar/ 39Ar age determinations, a new chronological model is proposed. Our study indicates that the activity of the volcanic belt was highly discontinuous and comprised at least five main episodes at 106-98Ma, 94-91Ma, 89-87Ma, 85.5-84Ma, and 82-79Ma. The new data allow a semi-quantitative estimate of the volcanic output rate for the observed part of the OCVB (area and volume approximately 10 5km 2 and 2.5×10 5km 3, respectively). The average extrusion rate for the entire lifetime of the volcanic belt ranges between 1.6 and 3.6×10 -5km 3yr -1km -1, depending on the assumed average thickness of the volcanic pile; the optimal value is 2.6×10 -5km 3yr -1km -1. Despite imprecise, such estimates infer the time-averaged volcanic productivity of the OCVB is similar to that of silicic LIPs and most active recent subduction-related volcanic areas of the Earth. However, the most extensive volcanic flare-ups at 89-87 and 85.5-84Ma had higher rates of over 9.0×10 -5km 3yr -1km -1.The main volumetric, temporal and compositional parameters of the OCVB are similar to those of silicic LIPs. This gives ground for discussion about the geodynamic setting of the latters, because the widely accepted definition of a LIP implies a strictly intraplate environment. Considering the genesis of the OCVB and other large provinces of silicic volcanism, we propose that residual thermal energy preserved in the continental crust after a previous major magmatic event may have been one of major reasons for high proportion of felsic rocks in a volcanic pile. In this scenario, underplating of mantle-derived basalts causes fast and extensive melting of still hot continental crust and generation of voluminous silicic magmas. © 2011 Elsevier B.V.

    DOI: 10.1016/j.jvolgeores.2011.12.011

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  • Space environment of an asteroid preserved on micrograins returned by the Hayabusa spacecraft 査読

    Eizo Nakamura, Akio Makishima, Takuya Moriguti, Katsura Kobayashi, Ryoji Tanaka, Tak Kunihiro, Tatsuki Tsujimori, Chie Sakaguchi, Hiroshi Kitagawa, Tsutomu Ota, Yusuke Yachi, Toru Yada, Masanao Abe, Akio Fujimura, Munetaka Ueno, Toshifumi Mukai, Makoto Yoshikawa, Jun'ichiro Kawaguchi

    Proceedings of the National Academy of Sciences of the United States of America   109 ( 11 )   E624 - E629   2012年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATL ACAD SCIENCES  

    Records of micrometeorite collisions at down to submicron scales were discovered on dust grains recovered from near-Earth asteroid 25143 (Itokawa). Because the grains were sampled from very near the surface of the asteroid, by the Hayabusa spacecraft, their surfaces reflect the low-gravity space environment influencing the physical nature of the asteroid exterior. The space environment was examined by description of grain surfaces and asteroidal scenes were reconstructed. Chemical and O isotope compositions of five lithic grains, with diameters near 50 mu m, indicate that the uppermost layer of the rubble-pile-textured Itokawa is largely composed of equilibrated LL-ordinary-chondrite-like material with superimposed effects of collisions. The surfaces of the grains are dominated by fractures, and the fracture planes contain not only sub-mu m-sized craters but also a large number of sub-mu m-to several-mu m-sized adhered particles, some of the latter composed of glass. The size distribution and chemical compositions of the adhered particles, together with the occurrences of the sub-mu m-sized craters, suggest formation by hypervelocity collisions of micrometeorites at down to nm scales, a process expected in the physically hostile environment at an asteroid's surface. We describe impact-related phenomena, ranging in scale from 10(-9) to 10(4) meters, demonstrating the central role played by impact processes in the long-term evolution of planetary bodies. Impact appears to be an important process shaping the exteriors of not only large planetary bodies, such as the moon, but also low-gravity bodies such as asteroids.

    DOI: 10.1073/pnas.1116236109

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  • Melt-peridotite reactions and fluid metasomatism in the upper mantle, revealed from the geochemistry of peridotite and Gabbro from the Horoman peridotite Massif, Japan 査読

    Sanjeewa P.K. Malaviarachchi, Akio Makishima, Eizo Nakamura

    Journal of Petrology   52 ( 6 )   1237 - 1237   2011年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    DOI: 10.1093/petrology/egr017

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  • Simultaneous Determination of Cd, In, Tl and Bi by Isotope Dilution-Internal Standardisation ICP-QMS with Corrections Using Externally Measured MoO+/Mo+ Ratios 査読

    Akio Makishima, Hiroshi Kitagawa, Eizo Nakamura

    Geostandards and Geoanalytical Research   35 ( 1 )   57 - 67   2011年3月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    A method for the simultaneous determination of Cd with In, Tl and Bi by isotope dilution-internal standardisation (ID-IS) ICP-QMS using the same aliquot for rare earth element and other trace element determinations was developed. Samples mixed with an enriched 149Sm spike were decomposed using a HF-HClO4 mixture, which was evaporated and then diluted with HNO3. After determination of Sm by ID-ICP-QMS and Cd, In, Tl and Bi concentrations were determined using the 149Sm intensity as an internal standard. The interference of MoO+ on Cd+ was corrected using the MoO+/Mo+ ratio separately measured using a Mo standard solution, and the validity of the externally determined oxide-forming ratio correction was evaluated. The MoO+/Mo+ ratios measured using the standard solution and samples were similar to 0.0002 and < 0.002, respectively. Detection limits for Cd, In, Tl and Bi in silicate samples were at levels of < 1 ng g-1 with a total uncertainty of < 7%. Cadmium in the carbonaceous chondrites, Orgueil (CI1), Murchison (CM2) and Allende (CV3) as well as Cd, In, Tl and Bi in the reference materials, JB-2, JB-3, JA-1, JA-2, JA-3, JP-1 (GSJ), BHVO-1, AGV-1, PCC-1 and DTS-1 (USGS) and NIST SRM 610, 612, 614 and 616 were determined to show the applicability of this method.Une methode pour la determination simultanee du Cd avec l'In, le Tl et le Bi par dilution isotopique a standardisation interne (ID-IS) ICP-QMS utilisant le meme aliquot pour la determination des terres rares et d'autres elements traces a ete developpe. Les echantillons melanges avec un ajout (' spike ') enrichi en 149Sm ont ete decomposes en utilisant un melange HF-HClO4, qui a eteevapore et, enfin, dilue avec HNO3. Apres la determination du Sm par ID-ICP-QMS, les concentrations en Cd, In, Tl et Bi ont ete determinees en utilisant l'intensite du 149Sm comme standard interne. L'interference de MoO+ sur Cd+ a ete corrige en utilisant le rapport MoO+/Mo+ mesure separement a l'aide d'une solution de Mo standard, et la validite de cette correction a eteevalue. Les rapports MoO+/Mo+ mesures a l'aide des solutions standards et des echantillons ont ete respectivement d'environ 0.0002 et inferieurs a 0.002. Les limites de detection pour le Cd, l'In, le Tl et le Bi dans les echantillons de silicate ont etea des niveaux inferieurs a 1 ng g-1 avec une incertitude totale inferieure a 7%. Le cadmium dans les chondrites carbonees : Orgueil (CI1), Murchison (CM2) et Allende (CV3) ainsi que le Cd, l'In, le Tl et le Bi dans les materiaux de reference : JB-2, JB-3, JA-1, JA-2, JA-3, JP-1 (GSJ), BHVO-1, AGV-1, PCC-1, DTS-1 (USGS) et NIST SRM 610, 612, 614 et 616 ont ete determines afin de demontrer l'applicabilite de cette methode.

    DOI: 10.1111/j.1751-908X.2010.00054.x

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  • Precise isotopic determination of Hf and Pb at sub-nano gram levels by MC-ICP-MS employing a newly designed sample cone and a pre-amplifier with a 1012 ohm register 査読

    Akio Makishima, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   25 ( 11 )   1712 - 1716   2010年11月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    Precise isotopic determination methods for Hf and Pb at sub-nano gram levels have been undertaken for this contribution utilizing the Neptune multiple collector ICP-MS (MC-ICP-MS) with a newly designed sample cone (the Jet cone) and a new pre-amplifier with a highly-resistive register of 1012 ohm. The Jet cone enhanced sensitivities 1.6 and 3 times for Hf and Pb, respectively. The Jet cone showed no significant improvements in reproducibility of Hf isotope analysis at &gt;1 ng compared to the normal cone, but the reproducibility improved considerably by half when Hf concentration of &lt;1 ng was measured. Thus, 0.3 and 0.8 ng of Hf can yield reproducibility (2SD in epsilon-unit) of 3 and 1.7, respectively. Reproducibility (RSD) of Pb-207/Pb-206, Pb-206/Pb-204, Pb-207/Pb-204 and Pb-208/Pb-204 were 0.026, 0.28, 0.33 and 0.36% using total Pb of 0.025 ng, and 0.02, 0.10, 0.10 and 0.08% using 0.05 ng, respectively. Thus, the Jet cone with the new pre-amplifier showed the best performance compared to the normal cone and pre-amplifier and are similar or even better than those obtained by the Pb-202-Pb-205 double-spike TIMS or multi-ion counting ICP-MS techniques.

    DOI: 10.1039/c0ja00015a

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  • Chromium isotope systematics of achondrites: Chronology and isotopic heterogeneity of the inner solar system bodies 査読

    Akane Yamakawa, Katsuyuki Yamashita, Akio Makishima, Eizo Nakamura

    Astrophysical Journal   720 ( 1 )   150 - 154   2010年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    The standard planetary formation models assume that primitive materials, such as carbonaceous chondrites, are the precursor materials of evolved planetesimals. Past chronological studies have revealed that planetesimals of several hundred kilometers in size, such as the Howardite-Eucrite-Diogenite (HED) parent body (Vesta) and angrite parent body, began their differentiation as early as similar to 3 million years of the solar system formation, and continued for at least several million years. However, the timescale of planetesimal formation in distinct regions of the inner solar system, as well as the isotopic characteristics of the reservoirs from which they evolved, remains unclear. Here we present the first report for the precise (53)Mn-(53)Cr ages of monomict ureilites. Chemically separated phases from one monomict ureilite (NWA 766) yielded the Mn-Cr age of 4564.60 +/- 0.67 Ma, identical within error to the oldest age preserved in other achondrites, such as angrites and eucrites. The (54)Cr isotopic data for this and seven additional bulk ureilites show homogeneous epsilon(54)Cr of similar to-0.9, a value distinct from other achondrites and chondrites. Using the epsilon(54)Cr signatures of Earth, Mars, and Vesta (HED), we noticed a linear decrease in the epsilon(54)Cr value with the heliocentric distance in the inner region of the solar system. If this trend can be extrapolated into the outer asteroid belt, the epsilon(54)Cr signatures of monomict ureilites will place the position of the ureilite parent body at similar to 2.8 AU. These observations imply that the differentiation of achondrite parent bodies began nearly simultaneously at similar to 4565 Ma in different regions of the inner solar system. The distinct epsilon(54)Cr value between ureilite and carbonaceous chondrite also implies that a genetic link commonly proposed between the two is unlikely.

    DOI: 10.1088/0004-637X/720/1/150

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  • Melt-peridotite reactions and fluid metasomatism in the upper mantle, revealed from the geochemistry of peridotite and gabbro from the Horoman peridotite massif, Japan 査読

    Sanjeewa P.K. Malaviarachchi, Akio Makishima, Eizo Nakamura

    Journal of Petrology   51 ( 7 )   1417 - 1445   2010年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    An investigation of the petrology and geochemistry of peridotites and gabbros in the Horoman massif, Hokkaido, Japan was undertaken to constrain geochemical processes in the upper mantle. Two types of sample were studied: one type comprises peridotites and gabbros forming thin layers varying from a few millimeters to centimeters in scale (thin-layer peridotites and gabbros); the other comprises thick layers (> 1 m scale; massive peridotites and gabbros). There is no clear trace element evidence for metasomatism in the thin-layer peridotites. Instead, they have melt-rock reaction textures interpreted in terms of the formation of secondary pyroxene at the expense of primary porphyroclastic olivine and dissolution of primary porphyroclastic pyroxene to form secondary olivine. The thin-layer gabbros also exhibit no metasomatic effects; they have incompatible element depleted trace element characteristics and mid-ocean ridge basalt (MORB)-like isotopic signatures consistent with the presence of a new type of gabbro that previously has not been described from the Horoman Massif. The whole-rock chemistry of the thin-layer peridotites and thin-layer gabbros can be explained by melt-peridotite reactions between isotopically highly depleted MORB mantle (represented by the thin-layer peridotites) and melt with geochemical affinity to Pacific MORB (represented by the thin-layer gabbros). Sm-Nd and Lu-Hf isotope systematics suggest that these reactions might have occurred at similar to 300 Ma. Some of the plagioclase lherzolites and all of the spinel lherzolites and harzburgites within the massive peridotites show enrichment in incompatible trace elements and more radiogenic Hf-Nd-Pb isotopic compositions than the incompatible-element depleted thin-layer peridotites. The analyzed massive gabbros are interpreted as subduction-related magmas formed in a MORB-source mantle wedge, which have subsequently interacted with a fluid or melt in the Hidaka subduction zone. Hf-Nd-Pb isotope systematics reveal that this interaction may have occurred at an age younger than similar to 50 Ma. Melt- and fluid-related processes occurring in the upper mantle are systematically identified from the samples of the Horoman Massif based on petrography, major and trace element, and Sr-Nd-Pb-Hf isotope geochemistry. These processes occurred in different tectonic settings such as the convecting oceanic mantle and supra-subduction zone mantle wedge and have variably modified the original chemistry of residual mantle protolith, formed by partial melting of a depleted MORB source mantle at similar to 1 Ga.

    DOI: 10.1093/petrology/egq024

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  • Determination of Fluorine and Chlorine by Pyrohydrolysis and Ion Chromatography: Comparison with Alkaline Fusion Digestion and Ion Chromatography 査読

    Qiaoyun Wang, Akio Makishima, Eizo Nakamura

    Geostandards and Geoanalytical Research   34 ( 2 )   175 - 183   2010年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    A method to determine F and Cl in silicate materials by employing pyrohydrolysis and ion chromatography (IC) is described. Pyrohydrolysis involved mixing a pulverised sample (similar to 40 mg) with V2O5 (similar to 160 mg) and heating to 1100 degrees C under a wet oxygen flow in a quartz tube. Recovery yields of F and Cl were similar to 97% using a NaF + NaCl standard solution. Detection limits of the pyrohydrolysis-IC method for silicate samples were 0.36 and 0.69 mu g g-1 for F and Cl, respectively. Fluorine and Cl concentrations were determined in the reference materials JB-2, JB-3 and JA-1 from the GSJ; BCR-2, BHVO-1, BHVO-2, AGV-1 and AGV-2 from the USGS; and NIST SRM 610, 612 and 614 glasses. Precisions (RSD) for determinations of F were 1-13% (except NIST SRM 614) and 2-19% for Cl, and were dependent on the concentration and blank correction. Most results obtained in this study were in good agreement with those of previous studies. In comparison, the Na2CO3 + ZnO fusion method at 900 degrees C showed that the yields of F and Cl by alkaline fusion systematically decreased with fusion duration time. The yields were 84% and 83% for JB-3, inferring that F and Cl were lost in this alkaline fusion.Une methode de determination des teneurs en F et Cl des materiaux silicates par pyrohydrolyse et chromatographie ionique (CI) est decrite. La pyrohydrolyse implique le melange entre un echantillon pulverise (similar to 40 mg) et du V2O5 (similar to 160 mg) et un chauffage a 1100 degrees C sous un flux d'oxygene humide dans un tube de quartz. Les rendements du F et du Cl ont ete d'environ 97% en utilisant une solution standard de NaF + NaCl. Les limites de detection de la methode CI-pyrohydrolyse pour les echantillons silicates ont ete respectivement de 0.36 et 0.69 mu g g-1 pour F et Cl. Les concentrations en F et Cl ont ete determinees dans les materiaux de reference JB-2, JB-3 et JA-1 du GSJ; BCR-2, BHVO-1, BHVO-2, AGV-1 et AGV-2 de l'USGS, et dans les verres de reference NIST SRM 610, 612 et 614. Les precisions (RSD) pour les determinations du F ont variees entre 1 et 13% (sauf pour le NIST SRM 614) et entre 2 et 19% dans le cas de celles du Cl. Elles dependent de la concentration et de la correction du blanc. La plupart des resultats obtenus dans cette etude sont en bon accord avec ceux des etudes precedentes. En comparaison, la methode de fusion utilisant le couple Na2CO3 + ZnO a 900 degrees C montre que les rendements de F et Cl par fusion alcaline diminuent systematiquement avec la duree de fusion. Les rendements ont ete respectivement de 84 et 83% pour JB-3, ce qui sous entend une perte de F et de Cl durant cette fusion alcaline.

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  • Precise determination of Cr, Mn, Fe, Co and Ni concentration by an isotope dilution-internal standardization method employing high resolution MC-ICP-MS 査読

    Akio Makishima, Akane Yamakawa, Katsuyuki Yamashita, Eizo Nakamura

    Chemical Geology   274 ( 1-2 )   82 - 86   2010年6月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    A new determination method for Cr, Mn, Fe, Co and Ni in silicate samples by an isotope dilution-internal standardization method (ID-IS)-high resolution (HR)-MC-ICP-MS has been developed. A silicate sample is dissolved into solution, and a Cr-spike solution is added into an aliquot of the sample solution. Then the solution is introduced into HR-MC-ICP-MS without chemical separation. Concentration of Cr is determined by ID, and those of Mn, Fe, Co and Ni are by ID-IS. Matrix effects were examined in detail, and negligible down to a dilution factor (DF; the weight of the sample solution over that of the sample in the solution) of similar to 3000 for basalt, and similar to 10(4) for peridotite and chondrite within an error range of +/-1%. ID-IS-FIR-MC-ICP-MS showed intermediate precision of similar to 1% for basalt and chondrite, which is comparable to ID-TIMS for Cr, Fe and Ni, and >10 times better than HR-ICP-MS, suggesting that this method is suitable for precise Mn-Cr and Fe-Ni chronometers. (C) 2010 Elsevier B.V. All rights reserved.

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  • Slab decarbonation and CO<inf>2</inf> recycling in the Southwestern Colombian volcanic arc 査読

    Maria I. Marín-Cerón, Takuya Moriguti, Akio Makishima, Eizo Nakamura

    Geochimica et Cosmochimica Acta   74 ( 3 )   1104 - 1121   2010年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The contribution of subducted carbonate sediments to the genesis of the Southwestern Colombian arc magmas was investigated using a comprehensive petrography and geochemical analysis, including determination of major and trace element contents and Sr, Nd, Hf and Pb isotope compositions. These data have been used to constrain the depth of decarbonation in the subducted slab, indicating that the decarbonation process continues into the sub-arc region, and ultimately becomes negligible in the rear arc. We propose on the basis of multi-isotope approach and mass balance calculations, that the most important mechanism to induce the slab decarbonation is the infiltration of chemically reactive aqueous fluids from the altered oceanic crust, which decreasingly metasomatize the mantle wedge, triggering the formation of isotopically different primary magmas from the volcanic front (VF) with relatively high Hf-176/Hf-177, high Sr-87/Sr-86, negative values of epsilon Nd and lower Pb isotopes compared to the rear arc (RA).The presence of more aqueous fluids at the volcanic front may increase the degree of decarbonation into carbonate-bearing lithologies. Moreover, with increasing pressure and temperature in the subduction system, the decrease in dehydration of the slab, leads to cessation of fluid-induced decarbonation reactions at the rear arc. This development allows the remaining carbonate materials to be recycled into the deep mantle. (C) 2009 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.gca.2009.10.031

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  • アスベスト小体と悪性胸膜中皮腫 査読

    中村栄三, 牧嶋昭夫, 岡部和倫

    感染・炎症・免疫   40   184 - 186   2010年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Chemical separation and mass spectrometry of Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial materials using thermal ionization mass spectrometry 査読

    Akane Yamakawa, Katsuyuki Yamashita, Akio Makishima, Eizo Nakamura

    Analytical Chemistry   81 ( 23 )   9787 - 9794   2009年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    A sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks was developed for precise and accurate determination of elemental concentration by the isotope dilution method (ID). The technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The method was tested using a variety of matrixes including bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-1b). Concentrations of each element was determined by thermal ionization mass spectrometry (TIMS) using W filaments and a Si-B-Al type activator for Cr, Fe, Ni, and Zn and a Re filament and silicic acid-H3PO4 activator for Cu. The method can be used to precisely determine the concentrations of these elements in very small silicate samples, including meteorites, geochemical reference samples, and mineral standards for microprobe analysis. Furthermore, the Cr mass spectrometry procedure developed in this study can be extended to determine the isotopic ratios of Cr-53/Cr-52 and Cr-54/Cr-52 with precision of similar to 0.05 epsilon and similar to 0.10 epsilon (1 epsilon = 0.01%), respectively, enabling cosmochemical applications such as high precision Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites.

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  • Precise elemental and isotopic analyses in silicate samples employing ICP-MS: Application of hydrofluoric acid solution and analytical techniques 招待 査読

    Akio Makishima, Ryoji Tanaka, Eizo Nakamura

    Analytical Sciences   25 ( 10 )   1181 - 1187   2009年10月

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    記述言語:英語   出版者・発行元:JAPAN SOC ANALYTICAL CHEMISTRY  

    In this review, a new classification of elements based on behavior in hydrofluoric acid (HF) solution is presented for the precise quantitative analysis of each element by inductively coupled plasma mass spectrometry (ICP-MS). The elements are divided into 7 groups: (1) "fluorophile" elements; (2) insoluble fluoride-forming elements; (3) "bromophile" or "iodophile" elements; (4) "oxophile" elements; (5) "aquaphile" elements; (6) bare cation elements; and (7) other elements. Especially, the importance of fluorophile and insoluble fluoride-forming elements in elemental analysis is described. Due to the elemental characteristics, these two groups of elements cannot be dissolved simultaneously in the same solution, and thus cannot be measured together. In addition, coprecipitation of the fluorophile elements with the insoluble fluorides occurs in some conditions and hinders accurate analysis. The peculiar conditions when the coprecipitation occurs are discussed, and the "Al-addition" and "Mg-addition" methods for overcoming these problems are described. In addition, some state-of-the-art analytical techniques in ICP-MS are shown, and future directions of the element analysis are presented.

    DOI: 10.2116/analsci.25.1181

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  • Determination of Ge, As, Se and Te in silicate samples using isotope dilution-internal standardisation octopole reaction cell ICP-QMS by normal sample nebulisation 査読

    Akio Makishima, Eizo Nakamura

    Geostandards and Geoanalytical Research   33 ( 3 )   369 - 384   2009年9月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    A method for the determination of Ge, As, Se and Te in silicate samples using isotope dilution-internal standardisation (ID-IS) octopole reaction cell (ORC) ICP-QMS by normal sample nebulisation was developed. The method does not involve either hydride generation or ion exchange. Germanium, Se and Te were determined by isotope dilution (ID), and As was determined by ID-IS. A silicate sample with an added Ge-Se-Te spike was digested with an HF-HNO3-HBr mixture, dried, re-dissolved with HF and the supernatant liquid was directly aspirated into an ORC-ICP-QMS instrument with He or H-2 gas. No matrix effects were observed down to a dilution factor (DF) of similar to 70 for Ge, Se and Te and DF of similar to 1000 for As, which resulted in 3s detection limits in silicates of 2, 1, 0.1 and 4 ng g-1, respectively. Advantages of the method are the simple sample introduction as well as a capability of determining S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by ID-IS-ICP-QMS/SFMS from the same solution. Furthermore, the total sample solution consumption was only 0.253 ml with DF = 2000. Therefore, only a 0.13 mg test portion was required. To demonstrate the applicability of this technique, Ge, As, Se and Te in eight silicate reference materials were determined, as well as S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta in four carbonaceous chondrites.

    DOI: 10.1111/j.1751-908X.2009.00014.x

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  • Accumulation of radium in ferruginous protein bodies formed in lung tissue: Association of resulting radiation hotspots with malignant mesothelioma and other malignancies 査読

    Eizo Nakamura, Akio Makishima, Kyoko Hagino, Kazunori Okabe

    Proceedings of the Japan Academy Series B: Physical and Biological Sciences   85 ( 7 )   229 - 239   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN ACAD  

    While exposure to fibers and particles has been proposed to be associated with several different lung malignancies including mesothelioma, the mechanism for the carcinogenesis is not fully understood. Along with mineralogical observation, we have analyzed forty-four major and trace elements in extracted asbestos bodies (fibers and proteins attached to them) with coexisting fiber-free ferruginous protein bodies from extirpative lungs of individuals with malignant mesothelioma,. These observations together with patients' characteristics suggest that inhaled iron-rich asbestos fibers and dust particles, and excess iron deposited by continuous cigarette smoking would induce ferruginous protein body formation resulting in ferritin aggregates in lung tissue. Chemical analysis of ferruginous protein bodies extracted from lung tissues reveals anomalously high concentrations of radioactive radium, reaching millions of dines higher concentration than that of seawater. Continuous and prolonged internal exposure to hotspot ionizing radiation from radium and its daughter nuclides could cause strong and frequent DNA damage in lung tissue, initiate different types of tumour cells, including malignant mesothelioma cells, and may cause cancers.

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  • Comprehensive analysis for major, minor and trace element contents and Sr-Nd-Pb-Hf isotope ratios in sediment reference materials, JSd-1 and MAG-1 査読

    B. Nagender Nath, Akio Makishima, Janine Noordmann, Ryoji Tanaka, Eizo Nakamura

    Geochemical Journal   43 ( 3 )   207 - 216   2009年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:GEOCHEMICAL SOC JAPAN  

    In view of the requirement of a well-characterized and easily available aquatic sediment reference material, a comprehensive analysis comprising of fifty major, minor and trace elements as well as Sr-Nd-Pb-Hf isotopes were carried out in the stream sediment reference material, JSd-1, issued by the Geological Survey of Japan. The data for marine sediment reference material, MAG-1, issued by U.S. Geological Survey is also obtained for comparison. The elements were divided into two groups: Group I and Group II. Elements in Group I form stable soluble ions in HNO3; and those in Group II form soluble oxo- and fluoro-complexes in HF, such as Zr, Nb, Hf, Ta, etc. For Group I, the sample was decomposed with HF in a tetra fluoro ethylene (TFE) bomb at 245 degrees C for 96 hrs with Mg addition. The elemental concentration was measured by quadrupole type inductively coupled plasma source mass spectrometry (ICP-QMS) and sector field type ICP-MS (ICP-SFMS) using isotope dilution-internal standardization (ID-IS) methods. The aliquot of the sample solution was passed through 3-step column chemistry for isotope ratio determination of Pb by Multiple collector (MC) ICP-MS and thermal ionization mass spectrometry (TIMS), and Sr and Nd by TIMS. For Group II elements, the sample was decomposed with H F in a TFE bomb with the same time and temperature settings. Zr, Mo, Sn, Sb and Hf were determined by I D, and Nb and Ta by ID-IS using ICP-QMS. The original JSd-1 powder showed heterogeneity for Group II elements, indicating insufficient pulverization and distribution. Thus, we further pulverized the powder and measured the concentration, which showed improved homogeneity. The aliquot for the re-pulverized powder was passed through 2-step column chemistry, and the Hf isotope ratio was determined by MC-ICP-MS. Thus a new data on the trace elements as well as Sr-Nd-Pb-Hf isotope ratios is provided for JSd-1 and MAG-1 in this paper.

    DOI: 10.2343/geochemj.1.0018

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  • Highly unradiogenic lead isotope ratios from the horoman peridotite in japan 査読

    Sanjeewa P.K. Malaviarachchi, Akio Makishima, Masaaki Tanimoto, Takeshi Kuritani, Eizo Nakamura

    Nature Geoscience   1 ( 12 )   859 - 863   2008年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Basalts at mid-ocean ridges are generated by partial melting of the Earth's upper mantle. As a result of this process, the upper mantle has become depleted over time in elements that are preferentially removed by melting(1-3). Although mid-ocean-ridge basalts have traditionally been thought to reflect the chemical composition of such depleted mantle(2-7), recent work has revealed the existence of domains in the upper mantle that are apparently not sampled by the basalts(8). Here we present the lead (Pb), neodymium (Nd) and hafnium (Hf) isotope compositions of peridotites from the Horoman orogenic massif in Japan, which is considered to represent the residues of melting of the upper mantle. These peridotites exhibit the lowest Pb isotope ratios reported from any known mantle material, along with high Nd and Hf isotope ratios. These data suggest that chemical depletion of the peridotites occurred around a billion years ago, and that they represent ancient mantle domains that have escaped convective stirring and homogenization. We suggest that such domains-if abundant in the mantle-may constitute a hitherto unrecognized reservoir with highly unradiogenic lead.

    DOI: 10.1038/ngeo363

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  • Multiple pulses of the mantle plume: Evidence from tertiary icelandic lavas 査読

    Hiroshi Kitagawa, Katsura Kobayashi, Akio Makishima, Eizo Nakamura

    Journal of Petrology   49 ( 7 )   1365 - 1396   2008年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    We present major and trace element concentrations and Sr-Nd-Hf-Pb isotope data for the c. 13-2 Ma Tertiary lavas from eastern Iceland. Our new geochemical results, together with published geological, geochronological, geochemical and geophysical data, are used to evaluate temporal changes in mantle sources contributing to the Tertiary Icelandic magmatism and the relative roles of these sources in magma productivity. The trace element and radiogenic isotopic compositions clearly distinguish three distinct end-member components in the Tertiary magmatism. Temporal variations in lava geochemistry can be attributed to changes in the relative contributions of these three end-member components to the erupted magmas and correlated with temporal variations in magma productivity. The extrusion of lavas with geochemically and isotopically enriched compositions was particularly pronounced at similar to 13-12 and 8-7 Ma, coincident in time with higher magma productivity. However, the geochemical characteristics of the lavas are different during these two periods: the 13-12 Ma lavas have more radiogenic Hf-176/Hf-177 and less radiogenic Pb-206/Pb-204 than those erupted from 8 to 7 Ma. The eruption of relatively depleted lavas, at around 10 Ma and younger than 6.5 Ma, is coincident with lower magma productivity. The correlation between the composition and productivity of the Tertiary lavas from eastern Iceland is probably due to periodic changes in the involvement of the enriched end-member component, followed by a gradation to periods dominated by the signature of the depleted end-member component and lower magma productivity, at an approximate frequency of 5 Myr.

    DOI: 10.1093/petrology/egn029

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  • Hawaiian double volcanic chain triggered by an episodic involvement of recycled material: Constraints from temporal Sr-Nd-Hf-Pb isotopic trend of the Loa-type volcanoes 査読

    Ryoji Tanaka, Akio Makishima, Eizo Nakamura

    Earth and Planetary Science Letters   265 ( 3-4 )   450 - 465   2008年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER  

    The two parallel loci of recent Hawaiian volcanoes, Kea and Loa, have been regarded as the best targets to interpret the chemical structure of an upwelling mantle plume derived from the lower mantle. Here we show that the Sr-Nd-Hf-Pb isotopic data of the shield-building lavas along the Loa locus form a systematic trend from the main shield stage of Koolau (>2.9 Ma) to the active Loihi volcanoes. During the growth of the Koolau volcano, the dominant material in the melting region successively changed from the proposed KEA, DMK (depleted Makapuu), to EMK (enriched Makapuu) components. The proportion of EMK, dominated by a recycled mafic component, is typified by some Koolau Makapuu-stage and some Lanai lavas. Subsequently, the EMK component decreased and LOIHI component increased toward the Loihi lavas. The temporal coincidence between the episodically elevated magma production rate and the abrupt appearance of the typical Loa-type lavas that is restricted to the last 3 Myr should be linked to magma genesis. We suggest that the abrupt appearance of Loa-type magmatism should be attributed to the transient incorporation of the relatively dense recycled material and surrounding less degassed lower mantle material that accumulated near the core-mantle boundary into the upwelling plume. This episodic involvement could have been trigged by episodic thermal pulses and buoyancy increases in the plume. The continuous appearance of Kea-type lavas during the long history of Hawaiian-chain magmatism and the larger magma volume of Kea-type lavas relative to that of the Loa-type lavas in the last 3 Myr indicate that the Kea locus is closer to the thermal centre of the Hawaiian plume relative to that of the Loa locus. (C) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.epsl.2007.10.035

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  • New sequential separation procedure for Sr, Nd and Pb isotope ratio measurement in geological material using MC-ICP-MS and TIMS 査読

    Akio Makishima, B. Nagender Nath, Eizo Nakamura

    Geochemical Journal   42 ( 3 )   237 - 246   2008年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:GEOCHEMICAL SOC JAPAN  

    A new 3-step sequential separation chemistry for Sr, Nd and Pb from silicate samples, which is suitable for isotope analysis by MC-ICP-MS as well as TIMS, has been developed. The chemistry is designed to minimize the number of evaporation steps, enabling high throughput especially when MC-ICP-MS is employed. The sample solution in 0.5 mol 1(-1) HNO3 after digestion with HF-HCIO4, which is prepared for trace element analysis, can be directly used in the new chemistry. In the first column using Sr resin, Sr and Pb are collected. The recovered solution for Sr can be directly aspirated into MC-ICP-MS. The Pb solution is dried, re-dissolved, separated into two aliquots and measured by double spike MC-ICP-MS. Subsequently, LREEs are collected by the second column packed with cation exchange resin. Finally, Nd was purified from Sm using Ln resin in the third column. The recovered Nd solution can also be directly nebulized into MC-ICP-MS. The Sr and Nd isotope ratios for the standard material JB-3 (basalt) from the Geological Survey of Japan by MC-ICP-MS and TIMS were reported to verify the chemistry and mass spectrometry developed in this study.

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  • New preconcentration technique of Zr, Nb, Mo, Hf, Ta and W employing coprecipitation with Ti compounds: Its application to Lu-Hf system and sequential Pb-Sr-Nd-Sm separation 査読

    Akio Makishima, Eizo Nakamura

    Geochemical Journal   42 ( 2 )   199 - 206   2008年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:GEOCHEMICAL SOC JAPAN  

    A new preconcentration technique of Zr, Nb, Mo, Hf, Ta and W has been invented employing coprecipiation with Ti compounds. Silicate samples were digested by HF with addition of Ti. Subsequent drying with HClO4 resulting in complete elimination of fluorine produces Ti compounds (oxide/hydroxides). The sample was then dissolved with dilute nitric acid and centrifuged, and the residual Ti compounds were collected. The Ti compounds forming from 2 mg of Ti without matrix elements concentrate 84-98% of Zr, Nb, Mo, Hf, Ta and W. In 20 mg basaltic and 50 mg peridotitic matrices, the addition of I nig of Ti was appropriate and gave yields of 46-69 and 54-79%, respectively, for Zr, Nb, Mo, Hf, Ta and W. Exploiting this preconcentration, sequential separation protocols of Hf, Pb, Sr, Lu, Nd and Sm for isotope analysis are developed with total blanks of 16, 11, 60, 2.4, 3 and 0.4 pg, respectively. The method is suitable for Lu-Hf system studies with capability of simultaneous separation of Pb, Sr, Nd and Sm from the same sample digest as well as isotopic anomaly studies of Zr, Mo and W. As application examples, accurate Lu-Hf data and Pb isotope ratios were obtained for basalt (JB-3) and peridotite (JP-1) by MC-ICP-MS.

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  • Precise measurement of 228Ra/226Ra for 226Ra determination employing total integration and simultaneous 228Th correction by multicollector ICP-MS using multiple ion counters 査読

    Akio Makishima, Takele A. Chekol, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   23 ( 8 )   1102 - 1107   2008年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    A precise method of measuring Ra-228/Ra-226 for Ra-226 determination used in U-series disequilibrium studies has been developed using the total integration method with simultaneous 228Th isobaric interference correction by multicollector ICP- MS with multiple ion counters (MIC). A sample solution of 0.2 ml was separately taken into a test tube, and all Ra-226(+) and Ra-228(+) signals as well as Th-229(+) and (ThO+)-Th-228-O-16 from beginning to end were integrated simultaneously using four channeltrons, IC1, IC3, IC4 and IC5, respectively. Gains between IC1 and IC3 and the mass discrimination factor for Ra-228/ (226) Ra determination were canceled out by measurement of a Ra spike solution with an accurately known Ra isotope ratio determined by TIMS, with which samples were bracketed. The isobaric interferences of Th-228(+) were simultaneously corrected from the signal of (ThO+)-Th-228-O-16 and the oxide forming ratio of Th-228, which was separately determined by simultaneous measurements of Th-229(+) and 2(29)Th(16)O(+) by IC3 and IC5. The gains between IC3 and IC5 for the Th correction were also canceled out. The ion yield of Ra in MIC- ICP- MS was similar to 1.5%. The intermediate precision using 6.6, 3.3, 1.7, 0.83 and 0.41 fg of Ra-226 with Ra-228/Ra-226 similar to 5 was 0.33, 0.93, 0.76, 1.6 and 1.5%, respectively. The Ra-228/Ra-226 ratio showed no systematic change dependent on Th-228/Ra-228 up to 0.25, indicating the validity of the Th-228 correction. At similar amounts of Ra, our method gives intermediate precision values similar to or better than previous MC-ICP-MS and TIMS studies. The precision of the method was verified using another Ra spike with Ra-228/ Ra-226 = similar to 1 determined by TIMS. The analytical performance of the method was further investigated using the silicate samples JB-2 and JB-3 basalts issued by GSJ.

    DOI: 10.1039/b807431c

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  • Ancient recycled crust beneath the Ontong Java Plateau: Isotopic evidence from the garnet clinopyroxenite xenoliths, Malaita, Solomon Islands 査読

    Akira Ishikawa, Takeshi Kuritani, Akio Makishima, Eizo Nakamura

    Earth and Planetary Science Letters   259 ( 1-2 )   134 - 148   2007年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER  

    We present a Sr, Nd, Hf and Pb isotope investigation of a set of garnet clinopyroxenite xenoliths from Malaita, Solomon Islands in order to constrain crustal recycling in the Pacific mantle. Geological, thermobarometric and petrochemical evidence from previous studies strongly support an origin as a series of high-pressure (> 3 GPa) melting residues of basaltic material incorporated in peridotite, which was derived from Pacific convective mantle related to the Ontong Java Plateau magmatism. The present study reveals isotopic variations in the pyroxenites that are best explained by different extents of chemical reaction with ambient peridotite in the context of a melting of composite source mantle. Isotopic compositions of bimineralic gamet clinopyroxenites affected by ambient peridotite fall within the oceanic basalt array, similar to those of Ontong Java Plateau lavas. In contrast, a quartz-gaenet clinopyroxenite, whose major element compositions remain intact, has lower Pb-206/(204) Pb-Nd-143/(144) Nd and higher (87)sr/Sr-86-Pb-207/(204) Pb ratios than most oceanic basalts. These isotopic signatures show some affinity with proposed recycled sources such as the so-called EM-1 or DUPAL types. Constraints from major and trace element characteristics of the quartz-garnet clinopyroxenite, the large extent of Hf-Nd isotopic decoupling and the good coincidence of Ph isotopes to the Stacey-Kramers curve, all indicate that pollution of southern Pacific mantle occurred by the subduction or delamination of Neoproterozoic granulitic lower crust (0.5-1 Ga). This crustal recycling could have taken place around the suture of Rodinia supercontinent, a part of which resurfaced during mantle upwelling responsible for creating the Cretaceous Ontong Java Plateau. (c) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.epsl.2007.04.034

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  • Coprecipitation of Ti, Mo, Sn and Sb with fluorides and application to determination of B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by ICP-MS 査読

    Yinghuai Lu, Akio Makishima, Eizo Nakamura

    Chemical Geology   236 ( 1-2 )   13 - 26   2007年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER  

    We examined the coprecipitation behavior of Ti, Mo, Sn and Sb in Ca-Al-Mg fluorides under two different fluoride forming conditions: at < 70 degrees C in an ultrasonic bath (denoted as the ultrasonic method) and at 245 degrees C using a Teflon bomb (denoted as the bomb method). In the ultrasonic method, small amounts of Ti, Mo and Sn coprecipitation were observed with 100% Ca and 100% Mg fluorides. No coprecipitation of Ti, Mo, Sn and Sb in Ca-Al-Mg fluorides occurred when the sample was decomposed by the bomb method except for 100% Ca fluoride. Based on our coprecipitation observations, we have developed a simultaneous determination method for B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by Q-pole type ICP-MS (ICP-QMS) and sector field type ICP-MS (ICP-SFMS). 9-50 mg of samples with Zr-Mo-Sn-Sb-Hf spikes were decomposed by HF using the bomb method and the ultrasonic method with B spike. The sample was then evaporated and re-dissolved into 0.5 mol FI HF, followed by the removal of fluorides by centrifuging. B, Zr, Mo, Sn, Sb and Hf were measured by ID method. Nb and Ta were measured by the ID-internal standardization method, based on Nb/Mo and Ta/Mo ratios using ICP-QMS, for which pseudo-FI was developed and applied. When 100% recovery yields of Zr and Hf are expected, Nb/Zr and TAW ratios may also be used. Ti was determined by the ID-internal standardization method, based on the Ti/Nb ratio from ICP-SFMS. Only 0.053 ml sample solution was required for measurement of all 9 elements. Dilution factors of <= 340 were aspirated without matrix effects. To demonstrate the applicability of our method, 4 carbonaceous chondrites (Ivuna, Orgueil, Cold Bokkeveld and Allende) as well as GSJ and USGS silicate reference materials of basalts, andesites and peridotites were analyzed. Our analytical results are consistent with previous studies, and the mean reproducibility of each element is 1.0-4.6% for basalts and andesites, and 6.7-11% for peridotites except for TiO2. (c) 2006 Elsevier B.V All rights reserved.

    DOI: 10.1016/j.chemgeo.2006.08.007

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  • Precise determination of Pb isotope ratios by simple double spike MC-ICP-MS technique without Tl addition 査読

    Akio Makishima, B. Nagender Nath, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   22 ( 4 )   407 - 410   2007年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    A double-spike multicollector ICP-MS ( DS-MC-ICP-MS) technique for Pb isotope analysis without T1 addition is established and its analytical performance is examined in detail. This simple DS-MC-ICP-MS technique using 20 ng ml(-1) gave averages of 16.9417, 15.4988 and 36.7196 with reproducibilities of 0.007, 0.008 and 0.009% ( RSD, n = 35), respectively, for Pb-206/Pb-204, Pb-207/Pb-204 and Pb-208/Pb-204 in NIST 981 solution, corresponding to consumption of 4 ng of Pb in a pair of spiked and non-spiked measurements. The average is consistent with those obtained by previous studies by DS-TIMS and DS-MC-ICP-MS with T1 addition. The reproducibility ( RSD %) of Pb-206/Pb-204, Pb-207/Pb-204 and Pb-208/Pb-204 improves from 0.26, 0.54 and 0.69% to 0.0022, 0.0030 and 0.0029% as the Pb consumption during analysis increases from 20 pg to 11 ng. The reproducibility with 11 ng is similar to or even better than those by DS-TIMS, MC-ICP-MS with T1 addition, or with DS-T1 addition. The accuracy of the simple DS-MC-ICP-MS technique for Pb, including the column chemistry, is further confirmed by analysis of actual silicate sample, JB-3.

    DOI: 10.1039/b616021b

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  • Accurate determination of 234U/238U and 230Th/232Th for U-Th disequilibria studies by MC-ICP-MS with simple bracketing 査読

    Akio Makishima, Takele A. Chekol, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   22 ( 11 )   1383 - 1389   2007年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    Accurate determination methods for U-234/U-238 and Th-230/Th-232 using multiple collector (MC) ICP-MS with a single secondary electron multiplier through a retarding potential quadrupole filter (RPQ-SEM) have been developed. The RPQ-SEM yield and the instrumental mass discrimination were simultaneously corrected by the simple bracketing method which utilizes accurately determined standard solutions measured by TIMS. For the bracketing and as an evaluation of the precision of the method, four standard solutions, NBL-145 U and U-m for U, and Th-I and Th-II for Th, were prepared, and NBL-145 U and Th-I were used as bracketing standards. The U and Th amounts of 0.5-21 ng and 0.6-21 ng used in U-m and Th-II analyses gave intermediate precisions (2RSD) of 0.85-0.06 and 0.88-0.19%, respectively, and vary from TIMS measurements by <0.35 and <1.1%, respectively, which agrees with error values in TIMS analyses. To achieve similar intermediate precisions of 0.2 and 0.6% (2RSD) in the U and Th isotope analyses to that of TIMS, 3 and 2 ng of U and Th are sufficient. When only the isotope analysis is performed, the required amounts of U and Th can be reduced by half. The precision of the isotope analyses, as well as the concentration determinations, were further confirmed by analyses of U and Th separated from the GSJ standard basalt, JB-2.

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  • Purification of Hf in silicate materials using extraction chromatographic resin, and its application to precise determination of 176Hf/ 177Hf by MC-ICP-MS with 179Hf spike 査読

    Yinghuai Lu, Akio Makishima, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   22 ( 1 )   69 - 76   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

    A two-stage column purification method for Hf from Zr and other elements in silicate samples using the extraction chromatographic resin, UTEVA has been developed. In the first column, using an anion-exchange resin, AG 1X8, Hf, Zr and Ti were collected. In the second, using UTEVA, and after eliminating F- by evaporation with HClO4 and re-dissolution with H2O2 HNO3, Hf was purified from Ti and Zr, based on characteristic of the UTEVA resin that Hf distribution coefficient (K-d) decreases from 770 to 40, while Kd of Zr decreases less from 890 to 200, in 9 and 6 mol l(-1) HNO3, respectively. The recovery yield of Hf was B88% and total blank was similar to 4 pg. A MC-ICP-MS Hf isotope ratio determination method was also developed, which uses 179 Hf spike for simultaneous determination of the Hf concentration and Hf-176/Hf-177 ratio. Combining the chemistry and ICP-MS techniques, Hf-176/Hf-177 ratios in silicate reference materials were determined with and without the spike, which gave identical results, showing the applicability of this method.

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  • Determination of Os and Re isotope ratios at subpicogram levels using MC-ICPMS with solution nebulization and multiple ion counting 査読

    Akio Makishima, Eizo Nakamura

    Analytical Chemistry   78 ( 11 )   3794 - 3799   2006年6月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    A precise and accurate determination method of Os-187/ Os-188, Os-189/Os-188, and Re-185/Re-187 ratios of down to 0.2 pg of Os and 0.08 pg of Re using multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) with multiple ion counting has been developed. Os and Re were introduced into MC-ICPMS as 0.5 mol L-1 HF solutions through the desolvator, and Re-185, Os-187, Os-188, and Os-189 ions were detected simultaneously by four channeltrons. The Os and Re ratios were determined by the standard bracketing method, in which channeltron yields and mass discrimination factors are corrected together. Os and Re memories after 800-s wash were < 0.1% and negligible, typically 0.02 and 0.03%, respectively. Isotope ratios of Os-187/ Os-188, Os-189/Os-188, and Re-185/Re-187 were constant within error in the concentration ranges of 1-100, 1-40, and 0.4-5 pg mL(-1) with reproducibility (1 sigma) of 2.7-0.14, 0.33-0.10, and 0.41-0.19%, respectively. For analysis of larger amounts of Os and Re, the Faraday cup measurement was employed. The precision and reproducibility obtained in this study are comparable to those of N-TIMS and better than MC-ICPMS achieved so far with a capability of higher sample throughput with simpler sample preparation.

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  • Determination of major, minor and trace elements in silicate samples by ICP-QMS and ICP-SFMS applying isotope dilution-internal standardisation (ID-IS) and multi-stage internal standardisation 査読

    Akio Makishima, Eizo Nakamura

    GEOSTANDARDS AND GEOANALYTICAL RESEARCH   30 ( 3 )   245 - 271   2006年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:GEOSTANDARDS  

    A method for the determination of major, minor and trace elements in silicate samples by ICP-QMS and ICP-SFMS applying isotope dilution-internal standardisation (ID-IS) and multi-stage internal standardisation has been developed. Samples with an enriched isotope of Sm-149(spike) were decomposed by a HF/HClO4 mixture and stepwise drying and finally diluted. In ID-IS for trace element analyses by Q-pole type ICP-MS (ICP-QMS), the Sm concentration was determined by ID, while other trace elements (Li, Be, R6, Sr, Y, In, Cs, Ba, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, Bi, Th and U) were determined using the Sm-149 intensity as an internal standard. Major and minor elements were determined by multi-stage internal standardisation, with Na, Mg, Al, R Ca, V, Mn, Fe and Co measured by sector magnetic field type ICP-MS (ICP-SFMS) at middle resolution (MR; M/Delta M = similar to 3000) using Sr determined by ICP-QMS in the sample as the internal standard. Potassium, Sc, Ni, Cu, Zn and Ga were measured at high resolution (HR; M/Delta M similar to 7500) using the Sr concentration obtained by ICP-QMS or the Mn concentration obtained by ICP-SFMS at MR as internal standard. The merit of ID-IS is that accurate dilution of the sample is not required. Matrix effects on elemental ratios down to a dilution factor (DF) of 600 were not observed in either types of mass spectrometry. Pseudo-flow injection (FI), where transient signals were integrated, was used in ICP-QMS, while conventional continuous sample introduction was used in ICP-SFMS, resulting in total required sample solutions of 0.026 ml and 0.08 ml, respectively. Detection limits were low enough to determine these elements in depleted ultramafic rocks, and typical reproducibilities for basalts were 3% (Li-Be), 11% (Rb-U), 5% (In, Tl and Bi), 7% (Sc-Ga) and 3% (major elements). Carbonaceous chondrites including Orgueil (Cl1), Murchison (CM2) and Allende (CV3), as well as reference materials, JB-1, -2,-3, JA-1, -2,-3 and JP-1 (GSJ), BHVO-1, AGV-1, PCC-1 and DTS-1 (USGS), were analysed to show the applicability of this method.

    DOI: 10.1111/j.1751-908X.2006.tb01066.x

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  • Mg and Ca isotope fractionation during CaCO <inf>3</inf> biomineralisation 査読

    Veronica T.C. Chang, R. J.P. Williams, Akio Makishima, Nick S. Belshawl, R. Keith O'Nions

    Biochemical and Biophysical Research Communications   323 ( 1 )   79 - 85   2004年10月

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    掲載種別:研究論文(学術雑誌)  

    The natural variation of Mg and Ca stable isotopes of carbonates has been determined in carbonate skeletons of perforate foraminifera and reef coral together with Mg/Ca ratios to assess the influence of biomineralisation processes. The results for coral aragonite suggest its formation, in terms of stable isotope behaviour, approximates to inorganic precipitation from a seawater reservoir. In contrast, results for foraminifera calcite suggest a marked biological control on Mg isotope ratios presumably related to its low Mg content compared with seawater. The bearing of these observations on the use of Mg and Ca isotopes as proxies in paleoceanography is considered. © 2004 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2004.08.053

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  • 同位体希釈法と内標準法を併用した、ICP質量分析法によるLi, Be, Rb, Sr, Y, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Th, Uの同時測定法の開発

    牧嶋 昭夫, 北川 宙, 坂口 千恵, 中村 栄三

    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   237 - 237   2004年9月

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    記述言語:英語   出版者・発行元:日本鉱物科学会  

    同位体希釈法と内標準法を併用した、ICP質量分析法によるLi, Be, Rb, Sr, Y, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Th, Uの同時測定法の開発をおこなった。

    DOI: 10.14824/jampeg.2004.0.64.0

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  • Determination of lithium contents in silicates by isotope dilution ICP-AAS and its evaluation by isotope dilution thermal ionisation mass spectrometry 査読

    Takuya Moriguti, Akio Makishima, Eizo Nakamura

    Geostandards and Geoanalytical Research   28 ( 3 )   371 - 382   2004年

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    掲載種別:研究論文(学術雑誌)  

    A precise and simple method for the determination of lithium concentrations in small amounts of silicate sample was developed by applying isotope dilution-inductively coupled plasma-mass spectrometry (ID-ICP-MS). Samples plus a Li spike were digested with HF-HClO4, dried and diluted with HNO3, and measured by ICP-MS. No matrix effects were observed for 7Li/6Li in rock solutions with a dilution factor (DF) of ≥ 97 at an ICP power of 1.7 kW. By this method, the determination of 0.5 μg g-1 Li in a silicate sample of 1 mg can be made with a blank correction of < 1%. Lithium contents of ultrabasic to acidic silicate reference materials (JP-1, JB-2, JB-3, JA-1, JA-2, JA-3, JR-1 and JR-2 from the Geological Survey of Japan, and PCC-1 from the US Geological Survey) and chondrites (three different Allende and one Murchison sample) of 8 to 81 mg were determined. The relative standard deviation (RSD) was typically < 1.7%. Lithium contents of these samples were further determined by isotope dilution-thermal ionisation mass spectrometry (ID-TIMS). The relative differences between ID-ICP-MS and ID-TIMS were typically < 2%, indicating the high accuracy of ID-ICP-MS developed in this study.

    DOI: 10.1111/j.1751-908X.2004.tb00756.x

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  • Purification of Mg from low-Mg biogenic carbonates for isotope ratio determination using multiple collector ICP-MS 査読

    Veronica T.C. Chang, Akio Makishima, Nick S. Belshaw, R. Keith O'Nions

    Journal of Analytical Atomic Spectrometry   18 ( 4 )   296 - 301   2003年

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    掲載種別:研究論文(学術雑誌)  

    A technique for separation of Mg, with 100% yield from low-Mg biogenic carbonates has been developed suitable for high precision analysis of Mg isotopes by multiple-collector inductively coupled plasma mass spectrometry. Two separate stages of ion-exchange chromatography were carried out using cation exchange resin, AG50W-X12 with a Mg recovery >99.9%. The repeatability of the Mg isotope ratio measurement using this technique including chemistry and mass spectrometry is ±0.14‰ on δ26Mg and ±0.09‰ on δ25Mg at 95% confidence. This was demonstrated using a synthetic solution (Na : Mg : Ca : Sr = 2 : 1 : 100 : 1 in weight) over a period of six months. The robustness of the technique was further assessed by replicate analyses of three natural samples, seawater, foraminifera and dolomite. A total variation over 4.5‰ on δ26Mg was observed and the Mg isotope composition of seawater was 2.59 ± 0.14‰ on δ26Mg and 1.33 ± 0.09‰ on δ25Mg which were the highest isotope ratios among the samples measured. © The Royal Society of Chemistry 2003.

    DOI: 10.1039/b210977h

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  • Suppression of Zr, Nb, Hf and Ta coprecipitation in fluoride compounds for determination in Ca-rich materials 査読

    Ryoji Tanaka, Akio Makishima, Hiroshi Kitagawa, Eizo Nakamura

    Journal of Analytical Atomic Spectrometry   18 ( 12 )   1458 - 1463   2003年

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    掲載種別:研究論文(学術雑誌)  

    We have evaluated recovery yields of Zr, Nb, Hf and Ta, which are called high field strength elements (HFSE), in the synthetic Ca-Al-Mg-HF solution system using two different methods: at <70°C in an ultrasonic-bath (denoted as the ultrasonic method) and at 205°C using a TFE Teflon® bomb (denoted as the bomb method). Full recovery of HFSE into the supernatant HF solution was not achieved in cases where fluorite (CaF2) forms in the precipitate in both methods and sellaite (MgF2) forms in the ultrasonic method. In order to suppress fluorite precipitation, an 'Al-addition method' was developed in which Al solution is added to the sample before decomposition to change the matrix solution to a composition in which no fluorite forms. Using the Al-addition method, HFSE concentrations of Ca-rich materials were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) by an isotope dilution method for Zr and Hf and by a calibration curve method for Nb and Ta. Furthermore, we found isotopic disequilibria of Zr and Hf between sample and spike without Aladdition for Ca-rich samples, and that the Al-addition method was very effective in achieving isotopic equilibria and full recovery of HFSE, resulting in high accuracy in their determination. © The Royal Society of Chemistry 2003.

    DOI: 10.1039/b309948b

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  • Suppression of Zr, Nb, HF, and Ta co-precipitation during HF digestion of Ca-rich geological materials 査読

    Tanaka R, Kitagawa H, Makishima A, Nakamura E

    Geochimica Et Cosmochimica Acta   67 ( 18 )   A475 - 1463   2003年

  • Comment on "determination of total sulfur at microgram-per-gram levels in geological materials by oxidation of sulfur into sulfate with in situ generation of bromine using isotope dilution high resolution ICPMS" 招待

    W. Robert Kelly, Robert D. Vocke, Jacqueline L. Mann, Akio Makishima, Eizo Nakamura

    Analytical Chemistry   74 ( 24 )   6430 - 6432   2002年12月

  • High precision measurement of titanium isotope ratios by plasma source mass spectrometry 査読

    X. K. Zhu, A. Makishima, Y. Guo, N. S. Belshaw, R. K. O'Nions

    International Journal of Mass Spectrometry   220 ( 1 )   21 - 29   2002年9月

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    掲載種別:研究論文(学術雑誌)  

    A method using multiple-collector inductively coupled plasma source mass spectrometry for the precise measurement of Ti isotope composition in natural materials has been developed. Instrumental mass discrimination is corrected using a "standard-sample bracketing" approach by expressing the isotope ratios of samples relative to those of the bracketing standard. Variations in 47Ti/46Ti, 48Ti/46Ti, 49Ti/46Ti and 50Ti/46Ti ratios of samples are expressed in ε units which are deviations in parts per 104 from the same isotope ratios of the reference material. The long-term repeatability at the 2 standard deviation level is 0.4, 0.6, 0.7 and 0.8 ε units in terms of 47Ti/46Ti, 48Ti/46Ti, 49Ti/46Ti and 50Ti/46Ti ratio measurements, respectively. The technique reported here makes it possible for the first time that both mass-dependent fractionation and isotope anomalies of Ti isotopes in natural materials can be measured to high precision. © 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S1387-3806(02)00767-4

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  • Determination of chromium, nickel, copper and zinc in milligram samples of geological materials using isotope dilution high resolution inductively coupled plasma-mass spectrometry 査読

    Akio Makishima, Katsura Kobayashi, Eizo Nakamura

    Geostandards Newsletter   26 ( 1 )   41 - 51   2002年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    A simple and accurate method for the determination of Cr, Ni, Cu and Zn at μg g-1 levels in milligram-sized bulk silicate materials is reported using isotope dilution high-resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS) with a flow injection system. Silicate samples with Cr, Ni, Cu and Zn spikes were digested with HF-HBr and Br2, and subsequently decomposed at 518 K in a Teflon bomb. In this procedure, all sulfides and chromite, major hosts of these elements, were completely decomposed, thus allowing for isotope equilibration between the sample and spike. Magnesium and Al fluorides formed after the digestion of the sample were removed by centrifugation, and the supernatant was directly aspirated into a HR-ICP-MS at a mass resolution of 7500, where interfering oxide ions, ArO +, CaO+, TiO+, CrO+ and VO +, were separated from Cr+, Ni+, Cu+ and Zn+. No matrix effects were observed down to a dilution factor of 50. Detection limits for these elements in silicate samples were < 0.04 μg g-1. The effectiveness of the technique was demonstrated by the analysis of 13 to 40 mg test portions of USGS and GSJ silicate reference materials with a major element composition ranging from andesite to peridotite, in addition to 8-23 mg of the Smithsonian reference Allende. Both the reproducibility and the deviation from the reference value for most reference materials of various rock types were < 9%, and thus confirm that the method gives accurate analytical results for small sample sizes over a wide range of Cr, Ni, Cu and Zn contents. This method is, therefore, suitable for analysing small and/or precious bulk samples, such as meteorites, mantle peridotites and mineral separates, and for the characterisation of silicate and sulfide minerals for use as calibration samples in secondary ion mass spectrometry or laser ablation ICP-MS.

    DOI: 10.1111/j.1751-908X.2002.tb00622.x

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  • Separation of titanium from silicates for isotopic ratio determination using multiple collector ICP-MS 査読

    Akio Makishima, Xiang Kun Zhu, Nick S. Belshaw, R. Keith O'Nions

    Journal of Analytical Atomic Spectrometry   17 ( 10 )   1290 - 1294   2002年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    A new separation method of Ti from silicate materials is presented that is suitable for the determination of natural Ti isotope variations using multi-collector inductively coupled plasma source mass spectrometry (MC-ICP-MS). This method makes possible for the first time the separation of Ti from natural materials, with high purity, high recovery and no introduction of artificial mass fractionation. Following sample decomposition using HF, Ti is separated using a three-column procedure. In the first column using an anion-exchange resin, AG 1X8, major elements and the majority of trace elements are separated. In the second column, after eliminating F- by evaporation with HClO4 and re-dissolution with H2O2-HNO3, Ti is separated from Zr and Hf using a liquid-liquid extraction resin, U/TEVA. In the third column, which is the same as the first column, trace amounts of Al and P are further removed. Recovery yields were almost unity, and no Ti isotope fractionation occurred from the overall chemical processing. The reproducibilities (2σ) of the Ti isotope ratio measurement for a meteorite (eucrite) and a lamproite were <0.5ε for ε47Ti, ε48Ti and ε49Ti, and <1ε for ε50Ti, which were comparable to those for the pure Ti standard solution.

    DOI: 10.1039/b204349a

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  • A group separation method for ruthenium, palladium, rhenium, osmium, iridium, and platinum using their bromo complexes and an anion exchange resin 査読

    A. Makishima, M. Nakanishi, E. Nakamura

    Analytical Chemistry   73 ( 21 )   5240 - 5246   2001年11月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    A new group separation method for Re and PGE (Ru, Pd, Os, Ir, Pt) is described using a novel anion exchange chromatographic resin called TEVA. Re and PGEs are converted into bromo complexes by heating with HF-HBr mixture in a Teflon bomb at 518 K, by in situ-generated Br2 formed by reaction of HBr and HNO3. Distribution coefficients (Kd) of the bromo complexes onto TEVA resin in 0.1 M HBr with heating at 353 K for one night were 2200, 16000, 1600, 5500, 4000, and 17 000 for Ru, Pd, Re, Os, Ir, and Pt, respectively, thus allowing 97% recovery of Re and PGEs in 5 mL of solution by 0.1 mL of resin. These strongly bound Re and PGE bromo complexes are stripped and recovered >90% by the following three steps: (i) addition of 6 M HCI at 353 K and 2.2 M HCI-5 M HBr at 353 K; (ii) heating the resin in 6 M HCI at 353 K to convert the bromo complexes into the chloro complexes with weaker affinities to the resin; and (iii) sequential addition of the HCI-HBr mixture at room temperature and 7 M HI. Neither the elution profile nor the recovery yield for a 0.2-g geological sample showed significant changes, indicating minimal matrix effects for the geological samples. Total blanks were <14 pg for Ru, Pd, and Pt and <10 pg for Re, Os, and Ir. This new technique, therefore, is suitable for simultaneous determination of subnanogram per gram of Ru, Pd, Re, Os, Ir, and Pt and Os isotope analysis in geological, mineralogical, and environmental samples without direct addition of toxic reagents required in distillation/extraction of Os or oxidizing of Ir.

    DOI: 10.1021/ac010615u

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  • Determination of total sulfur at microgram per gram levels in geological materials by oxidation of sulfur into sulfate with in situ generation of bromine using isotope dilution high-resolution ICPMS 査読

    A. Makishima, E. Nakamura

    Analytical Chemistry   73 ( 11 )   2547 - 2553   2001年6月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    We have developed a new, simple, and accurate method for the determination of total sulfur at microgram per gram levels in milligram-sized silicate materials with isotope dilution high-resolution inductively coupled plasma mass spectrometry equipped with a flow injection system. In this method, sulfur can be quantitatively oxidized by bromine into sulfate with achievement of isotope equilibrium between the sample and spike. Detection limits for 32S+ and 34S+ in the ideal solution and silicate samples were 1 and 6 ng mL-1 and 0.07 and 0.3 μg g-1, respectively. The total blank was 46 ng, so that a 40-mg silicate sample containing 10 μg g-1 sulfur can be measured with a blank correction of < 10%. This total blank can be lowered to 8 ng if a low-blank air system is used for evaporations. To evaluate the applicability of this method, we analyzed not only silicate reference materials with sulfur content of 5.25-489 μg g-1 and sample sizes of 13-40 mg but also the Allende meteorite with a sulfur content of 2%. The reproducibility for various rock types was <9%, even though blank corrections in some samples of low sulfur content were up to 24%. This method is suitable for analyzing geological samples as well environmental samples such as soils, sediments, and water samples.

    DOI: 10.1021/ac001550i

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  • Formation and suppression of AlF<inf>3</inf> during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS and ID-TIMS 査読

    Hiroyuki Takei, Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

    Proceedings of the Japan Academy Series B: Physical and Biological Sciences   77 ( 1 )   13 - 17   2001年1月

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    掲載種別:研究論文(学術雑誌)  

    An aluminum fluoride, AlF3, forms during HF digestion of felsic rock samples, for trace element and isotope geochemistry, which use a Teflon bomb at high temperature and pressure. The AlF3 incorporates trace elements (Rb, Sr, Y, Cs, Ba, REE, Pb, Th, and U), and can not be decomposed by conventional methods such as evaporation with HClO4. The production of this AlF3 results in lower yields and poor accuracy in analyses of these trace elements by ICP-MS. The formation of AlF3 is controlled by the chemical composition of the rock samples, in particular, AlF3 does not form during decomposition of mafic samples with relatively high (Mg+Ca)/Al ratios. We have developed a new method to suppress the AlF3 formation, in which excess Mg is added to the sample prior to acid digestion in the bomb. This new method makes it possible to accurately determine the trace element compositions of higher-Al rock samples with lower concentrations of Mg and Ca (e.g. rhyolite and granite). In the trace element analyses by TIMS with isotope dilution techniques (ID-TIMS), AlF3 formation hinders the achievement of isotope equilibrium, resulting in erroneous results. However, the Mg-addition method removed this problem by suppression of AlF3 formation.

    DOI: 10.2183/pjab.77.13

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  • Precise analysis of 234U/238U ratio using UO<inf>2</inf>+ ion with thermal ionization mass spectrometry for natural samples 査読

    Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

    Chemical Geology   181 ( 1-4 )   1 - 12   2001年

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    掲載種別:研究論文(学術雑誌)  

    We have developed a new, highly precise method for U isotopic analysis using a thermal ionization mass spectrometry (TIMS) by measuring UO+2 ions emitted from a very small amount (100- 10 ng) of U. A new ionization activator, a silicic acid-diluted phosphoric acid solution, was found to be effective not only for producing a strong and stable UO+2 ion beam, but also for keeping the mass fractionation during measurement small and constant. U isotope analysis was carried out by a "dynamic multi collection" method using three Faraday cup collectors and a secondary electron multiplier in ion counting mode with RPQ (RPQ-SEM). For precise isotope analysis, baselines of the Faraday cups and a conversion factor between Faraday cups and the RPQ-SEM were precisely determined simultaneously with U isotope collection. Analytical precision and reproducibility of 234U/238U ratio ranged from 0.10% to 0.38% (2σmean) and from 0.13% to 0.31% (2σ), respectively, for 100-10 ng of U extracted from a natural rhyolitic obsidian. The precision and reproducibility were improved compared with previous studies, and thus, our method is especially useful for samples with very low abundance of U. © 2001 Elsevier Science B. V. All rights reserved.

    DOI: 10.1016/S0009-2541(01)00270-4

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  • Determination of titanium at μg g-1 levels in milligram amounts of silicate materials by isotope dilution high resolution inductively coupled plasma mass spectrometry with flow injection 査読

    Akio Makishima, Eizo Nakamura

    Journal of analytical atomic spectrometry   15 ( 3 )   263 - 267   2000年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    An accurate method for the determination of Ti at μg g-1 levels in milligram amounts of silicate materials with isotope dilution high-resolution inductively coupled plasma mass spectrometry equipped with flow injection system (ID-FI-HR-ICP-MS) is presented. The chemical procedure requires HF digestion of the sample with the Ti spike, subsequent evaporation and dissolution of Ti with HF in order to separate from Mg and Ca fluorides formed after the digestion of the sample. A 10 mg silicate sample containing 0.002% TiO2 was measured with a blank correction of <5%. To demonstrate the applicability of this method, peridotite reference materials, PCC-1 and DTS-1, from the US Geological Survey (USGS) and JP-1 from the Geological Survey of Japan (GSJ) were analyzed (12-33 mg), to determine TiO2 content. The reproducibility was 3% for these peridotites with TiO2 contents of 0.003-0.004%. This method also gave TiO2 contents in BCR-1, BHVO-1 and AGV-1 from USGS and JB-1, -2, -3, JA-1, -2, and -3 from GSJ with reproducibility of 1-5% using test portions of 6-18 mg.

    DOI: 10.1039/a909020g

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  • Evaluation of the coprecipitation of incompatible trace elements with fluoride during silicate rock dissolution by acid digestion 査読

    Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

    Chemical Geology   157 ( 3-4 )   175 - 187   1999年5月

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    掲載種別:研究論文(学術雑誌)  

    Insoluble fluoride precipitates which form during HF digestion of mafic silicate rocks coprecipitate in their structures the trace elements such as Rb, Sr, Y, Cs, Ba, REE, Pb, Th and U, thus hindering their accurate determination. We have estimated quantitatively the coprecipitation of trace elements into such fluorides, and suggest an effective method of digestion that can suppress completely fluoride precipitation. Conventional acid digestion of three samples of mafic and ultramafic silicate rocks resulted in the precipitation of sticky material and very poor yields of certain trace element in the resultant solution. XRD analysis indicated that the precipitates were composed of fluorides such as CaAlF5, CaMg2Al2F12, Na0.88Mg0.88Al1.12(F,OH)6 · H2O and MgF2, the formation of which depended on the major element composition of the rock sample. Coprecipitation of trace elements appeared to be strongly controlled by both ionic radius and valency of the elements as well as the species of the host fluoride precipitate, resulting in selective losses of the elements into these fluorides. On the other hand, almost 100% of the trace elements were recovered using larger amounts of HCIO4 than is conventionally used and evaporating the sample to dryness in a step-wise fashion. Using this method, white precipitates were formed as oxides of high field strength elements after decomposition of the sample. Coprecipitation of trace elements of interest in this study with the oxides is negligible except for Th for which 0.5-3.2% by weight was coprecipitated probably as the insoluble oxide. As our method also results in negligible blank values, it can be used for both the accurate determination of trace element using ICP-MS as well as isotope analysis using TIMS.

    DOI: 10.1016/S0009-2541(98)00206-X

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  • Determination of molybdenum, antimony and tungsten at sub μg g -1 levels in geological materials by ID-FI-ICP-MS 査読

    Akio Makishima, Eizo Nakamura

    Geostandards Newsletter   23 ( 2 )   137 - 148   1999年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    We have developed a rapid and accurate method for the determination of Mo, Sb and W in geological samples using isotope dilution inductively coupled plasma-mass spectrometry with a flow injection system (ID-FI-ICP-MS). The chemical procedure requires HF digestion of the sample with a Mo-Sb-W mixed spike, subsequent evaporation and dissolution of Mo, Sb and W from Mg and Ca fluorides with HF. Recovery yields of Mo, Sb and W in the extraction were > 94% for samples of peridotite, basalt and andesite composition, with the exception of W in samples of peridotite composition for which recovery was 81%. No matrix effects were observed in the determination of the isotope ratios of Mo, Sb and W in solutions prepared from peridotite, basalt and andesite samples down to a dilution factor of 100. Detection limits of Mo, Sb and W in silicate materials were at the several ng g-1 level. Analysis of the silicate reference materials PCC-1, DTS-1, BCR-1, BHVO-1, AGV-1 from the US Geological Survey and JP-1, JB-1, -2, -3, JA-1, -2, and -3 from the Geological Survey of Japan as well as the Smithsonian reference Allende powder yielded reliable Mo, Sb and W concentrations. The repeatability in the analysis of basalts and andesites was < 9%. This technique requires only 0.2 ml sample solution, and is therefore suitable for analyzing small and/or precious samples such as meteorites, mantle peridotites and their mineral separates.

    DOI: 10.1111/j.1751-908X.1999.tb00569.x

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  • Determination of zirconium, niobium, hafnium and tantalum at ng g -1 levels in geological materials by direct nebulisation of sample HF solution into FI-ICP-MS 査読

    Akio Makishima, Eizo Nakamura, Toshio Nakano

    Geostandards Newsletter   23 ( 1 )   7 - 20   1999年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    We have developed a rapid and accurate method to determine Zr, Nb, Hf and Ta (denoted as HFSE) in geological samples by inductively coupled plasma-mass spectrometry fitted with a flow injection system (FI-ICP-MS). The method involves sample decomposition by HF followed by HF dissolution of HFSE coprecipitated with insoluble Mg and Ca fluoride residues formed during the initial HF attack. This HF solution was directly nebulized into an ICP mass spectrometer. An external calibration curve method and an isotope dilution method (ID) were applied for the determination of Nb and Ta, and of Zr and Hf, respectively. Recovery yields of HFSE were, 96% for peridotite, basalt and andesite compositions, apart from Zr and Hf for peridotite (> 85%). No matrix effects for either signal intensities of HFSE or isotope ratios of Zr and Hf were observed in basalt, andesite and peridotite solutions down to a dilution factor of 100. Detection limits in silicate rocks were 40, 2, 1 and 0.1 ng g-1 for Zr, Nb, Hf and Ta, respectively. This technique required only 0.1 ml of sample solution, and thus is suitable for analysing small and/or precious samples such as meteorites, mantle peridotites and their mineral separates. We also present newly determined data for the Zr, Nb, Hf and Ta concentrations in USGS silicate reference materials DTS-1, PCC-1, BCR-1, BHVO-1 and AGV-1, GSJ reference materials JB-1, -2, -3, JA-1, -2 and -3, and the Smithsonian reference Allende powder.

    DOI: 10.1111/j.1751-908X.1999.tb00555.x

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  • Separation of thorium and uranium from silicate rock samples using two commercial extraction chromatographic resins 査読

    Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

    Analytical Chemistry   71 ( 1 )   135 - 141   1999年

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    掲載種別:研究論文(学術雑誌)  

    A new chemical separation technique to isolate Th and U from silicate rocks was established by using two kinds of commercial extraction Chromatographic resins. In the first column procedure, with U/TEVA·spec resin, almost all elements except Th and U were eluted by 4 M HNO3. Th was then separated by using 5 M HC1, and U was finally isolated by successive addition of 0.1 M HNO3. A significant amount of Zr still remained in the Th fraction, which was then further purified in the second column stage using TEVA·spec resin. In the second procedure, Zr was eluted first by using 2 M HNO3, and then Th was collected by 0.1 M HNO3. Both the Th and U fractions obtained by these procedures were sufficiently pure for thermal ionization mass spectrometric (TIMS) analysis. Recovery yields of Th and U exceeded 90%, and total blanks were <19 pg for Th and <10 pg for U. Our method has advantages over previous methods in terms of matrix effects, tailing problems, and degree of isolation. Since Th and U are effectively separated without suffering any matrix interference from coexisting cations and anions, this technique can be used not only for the analysis of igneous rock samples but also for the analysis of soils, marine sediments, carbonates, phosphates and seawater, groundwater, and surface water. © 1998 American Chemical Society.

    DOI: 10.1021/ac9805807

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  • Determination of Boron in Silicate Samples by Direct Aspiration of Sample HF Solutions into ICPMS 査読

    Akio Makishima, Eizo Nakamura, Toshio Nakano

    Analytical Chemistry   69 ( 18 )   3754 - 3759   1997年9月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    A rapid and precise technique for the determination of boron content in silicate rocks was developed by employing isotope dilution inductively coupled plasma mass spectrometry with a flow injection system (FI-ID-ICPMS). The sample was decomposed with HF and mannitol, dried to remove silicon as gas, and redissolved with HF to extract boron from the fluoride residue. Ultimately, the HF solution was directly aspirated into the ICPMS. The total procedural blank was 0.08-0.36 ng. No matrix-induced mass discrimination was observed in the rock solution for dilution factors of up to 110. The present method is capable of determining 1 μg g-1 boron in a 1 mg silicate rock sample with blank correction of <20%. Replicate analyses of USGS rock standards, PCC-1, BCR-1, and AGV-1, and GSJ rock standards, JB-1, JB-2, JB-3, JA-1, JA-2, and JA-3, yielded reproducibilities (RSD) of <2%. These results were identical with those obtained by ID thermal ionization mass spectrometry within the analytical errors. These results indicate that the present method allows the precise determination of the boron content in a small sample of silicate materials with simple handling, resulting in the extremely low procedural blank of boron.

    DOI: 10.1021/ac970383s

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  • Sr, Nd and Pb isotope systematics of Akagi volcano, Northeast Japan: Implications for interaction between island arc magma and lower crust 査読

    Katsura Kobayashi, Eizo Nakamura, Tomoyuki Shibata, Akio Makishima

    Proceedings of the Japan Academy Series B: Physical and Biological Sciences   73 ( 5 )   69 - 73   1997年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Isotopic compositions of Sr, Nd and Pb and REE concentrations have been determined for samples from "isotopically anomalous" Akagi volcano locating on the volcanic front of Northeast Japan Arc. The Sr isotopic compositions show a large variation with highly enriched isotope character (87Sr/86Sr=0.7060 to 0.7088) compared to those from other volcanoes on the front. The Nd isotopic compositions, ranging from εNd = -0.40 to -8.6, have a negative correlation with the Sr isotopic compositions. The Pb isotopic data along with Sr and Nd isotope systematics clearly indicate that the isotopic variations of Akagi volcano were caused by a two-component mixing between an end member isotopically similar to the primary magma on the volcanic front of Northeast Japan Arc and a lower crustal component. Chondrite-normalized REE patterns of Akagi samples show U-shaped, HREE-depleted pattern with positive Eu anomaly. Such REE features may have been developed by fractionation of amphibole formed by the reaction between a fluid-rich magma and clinopyroxene in granulitic lower crust. The fluid-rich magma could be originated from a highly metasomatized mantle wedge caused by the dehydration of oceanic slabs of the Pacific plate and the overlapping Philippine Sea Plate. Such a unique tectonic setting could result in higher water supply to the source region of magma than normal circumstances and thereby generating fluid-rich magma which could enhance assimilation of lower crust beneath Akagi volcano.

    DOI: 10.2183/pjab.73.69

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  • Suppression of matrix effects in ICP-MS by high power operation of ICP: Application to precise determination of Rb, Sr, Y, Cs, Ba, REE, Pb, Th and U at ng g-1 levels in milligram silicate samples 査読

    Akio Makishima, Eizo Nakamura

    Geostandards Newsletter   21 ( 2 )   307 - 319   1997年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    We found that the suppression of signals for 88Sr, 140Ce and 238U in rock solution caused by rock matrix in ICP-MS (matrix effects) was reduced at high power operation (1.7 kW) of the ICP. To make the signal suppression by the matrix negligible, minimum dilution factors (DF) of the rock solution for Sr, Ce and U were 600, 400 and 113 at 1.1, 1.4 and 1.7 kW, respectively. Based on these findings, a rapid and precise determination method for Rb, Sr, Y, Cs, Ba, REE, Pb, Th and U using Fl (flow injection)-ICP-MS was developed. The amount of the sample solution required for FI-ICP-MS was 0.2 ml, so that 1.8 mg sample was sufficient for analysis with a detection limit of several ng g-1. Using this method, we determined the trace element concentrations in the USGS rock reference materials, DTS-1, PCC-1, BCR-1 and AGV-1, and the GSJ rock reference materials, JP-1, JB-1, -2, -3, JA-1, -2 and -3. The reproducibilities (RSD%) in replicate analyses (n=5) of BCR-1, AGV-1, JB-1, -2, -3, JA-1, -2, and -3 were < 6%, and typically 2.5%. The difference between the average concentrations of this study for BCR-1 and those of the reference values were < 2%. Therefore, it was concluded that the method can give reliable data for trace elements in silicate rocks.

    DOI: 10.1111/j.1751-908X.1997.tb00678.x

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  • インコンパティブル元素の挙動の解明へ向けた,新しい実験的・実証的手法の開発 招待 査読

    牧嶋昭夫

    地球化学   31   27 - 34   1997年

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • 同位体地球化学から見たアイスランド I. アイスランドホットスポットの同位体地球化学的特徴 査読

    牧嶋 昭夫

    岩鉱 : 岩石鉱物鉱床学会誌 : journal of mineralogy, petrology and economic geology   90 ( 11 )   379 - 387   1995年11月

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    担当区分:筆頭著者   記述言語:日本語   出版者・発行元:日本岩石鉱物鉱床学会  

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  • 同位体地球化学から見たアイスランド. II. アイスランドのフェルシックな火山岩の成因. 査読

    牧嶋昭夫

    岩鉱   90   413 - 413   1995年

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Ce isotope ratios of N-type MORB 査読

    Akio Makishima, Akimasa Masuda

    Chemical Geology   118 ( 1-4 )   1 - 8   1994年12月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    Isotope ratios of Ce, Nd and Sr, and light rare-earth elements (La, Ce, Nd and Sm) concentrations were measured for sixteen N-type MORB samples from DSDP Sites 420, 421, 429, 597B and 597C (East Pacific Rise), 504B (Costa Rica Rift), and 395, 519A, 522B, 562 and 564 (Mid Atlantic Ridge). All the samples were confirmed as N-type MORB based on Nd and Sr isotope ratios, and LREE patterns. The Ce isotope ratios ranged from 0.0225616 (ε{lunate}Ce = - 1.6) to 0.0225633 (ε{lunate}Ce = - 1.0). Averages of ε{lunate}Ce and ε{lunate}Nd of N-type MORB were - 1.4 and 9.5, respectively. The average of ε{lunate}Ce is quite different from previous estimates. We propose that ε{lunate}Ce = - 1.4 should be used as the typical MORB Ce isotope ratio in future studies. © 1994.

    DOI: 10.1016/0009-2541(94)90166-X

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  • ジルコンをめぐる最近の話題-3-ジルコンの希土類元素地球化学 査読

    牧嶋 昭夫, 中村 栄三

    岩鉱   89 ( 1 )   p1 - 14   1994年1月

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    担当区分:筆頭著者   記述言語:日本語   出版者・発行元:日本岩石鉱物鉱床学会  

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  • Search for p-isotopic anomaly of cerium in the bulk Allende meteorite 査読

    Akio Makishima, Akimasa Masuda

    GEOCHEMICAL JOURNAL   28 ( 2 )   115 - 122   1994年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    LREE (La, Ce, Nd and Sm) concentrations, and 143Nd/144Nd and 138Ce/142Ce ratios of two powder aliquots from the bulk Allende meteorite (BAM) were measured to investigate p-isotopic anomalies of Ce. Initial Ce isotope ratios of the two aliquots were calculated assuming an age of 4.56 Ga, identical with ages of other chondrites or eucrites. From the data, we conclude that there are no recognizable p-isotopic anomalies in BAM. This suggests that the existence of p-isotopic anomalies of other REE in BAM is unlikely. Our data can not, however, rule out the possibility that this is only caused by averaging of heterogeneous distribution of p-isotopic anomalies. © 1994, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

    DOI: 10.2343/geochemj.28.115

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  • ジルコンをめぐる最近の話題-2-重鉱物の晶出条件と希土類元素の分配 査読

    牧嶋 昭夫, 中村 栄三

    岩鉱   88 ( 12 )   p533 - 547   1993年12月

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:日本岩石鉱物鉱床学会  

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  • Primordial Ce isotopic composition of the solar system 査読

    Akio Makishima, Akimasa Masuda

    Chemical Geology   106 ( 3-4 )   197 - 205   1993年6月

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    Ce and Nd isotope ratios and REE contents of one carbonaceous chondrite (Murchison), 3 ordinary chondrites (Granès, Holbrook and Barwise) and 4 achondrites (Camel Donga, Juvinas, two pieces of Millbillillie) were measured. For the Ce isotope analysis of meteorite samples the new chemistry for extracting Ce from the gel formed after decomposition of ∼1-g chondrite sample with Mg content of 20% was developed with a recovery yield of 80%. The initial Ce isotope ratio of each meteorite sample was calculated with the assumption that the age of meteorite samples is 4.56 Ga, and the average value was obtained to be 138Ce/142Ce-0.0225321 ± 0.0000007 (2σ), which is considered to be the primordial Ce isotopic composition of the solar system. The average of the present-day Ce isotope ratios of the chondrites of this study and that previously published by Shimizu et al. is 0.0225653, which suggests that the estimation of the Ce isotope ratio of the present-day bulk Earth of 0.0225652 that was published by Makishima and Nakamura is convincing. The Ce isotope ratio of the present-day bulk Earth of 0.0225652 gives the 138La/142Ce ratio of the bulk Earth to be 0.00306 ± 0.00006 (2σ), which corresponds to La/Ce = 0.375 ± 0.007 (2σ). We propose that the La/Ce ratio of 0.375 represents that of the bulk Earth or CHUR. © 1993.

    DOI: 10.1016/0009-2541(93)90026-F

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  • New constraints on the 138La β-decay constant based on a geochronological study of granites from the Yilgarn Block, Western Australia 査読

    Akio Makishima, Eizo Nakamura, Syun iti Akimoto, Ian H. Campbell, Robert I. Hill

    Chemical Geology   104 ( 1-4 )   293 - 300   1993年2月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    The β-decay constant of 138La has been geochronologically determined using Archean granites from the Yilgarn Block, Western Australia. RbSr and SmNd mineral isochron ages were obtained for the two granite samples, which are nearly identical with the ion microprobe UPb zircon ages. This agreement indicates that the closure date for these samples is the same, within analytical error, making them suitable for geochronological estimation of the β-decay constant for 138La. Applying a new method of Ce isotope analysis, with analytical reproducibility of ±0.008%, LaCe isotope data for the studied samples resulted in precise mineral isochrons. Based on these internal mineral isochrons and ages determined by other geological clocks, the β-decay constant for 138La was estimated to be (2.33 ± 0.24)·10-12a-1 (2σ). © 1993.

    DOI: 10.1016/0009-2541(93)90158-F

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  • ジルコンをめぐる最近の話題, I.U-Pb法によるジルコン年代学 査読

    牧嶋昭夫

    岩鉱   88   496 - 516   1993年

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • p-核種の生成とその同位体比異常 査読

    牧嶋 昭夫, 其 魯, 増田 彰正

    地球化学   26 ( 1 )   41 - 50   1992年

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    担当区分:筆頭著者   記述言語:日本語   出版者・発行元:日本地球化学会  

    The origin of p-isotopes (proton rich isotopes) and their isotopic anomalies are reviewed in this article. The p-isotopes (84Sr,124Xe, 130Ba, 144Sm, 196Hg, etc.) are heavy isotopes (A≧74) which cannot be synthesized by s-process or r-process. The p-isotopes are considered to be produced by the transmutation of heavy elements into lighter p-isotopes via a series of (γ, n), (γ, p) and (γ, α) reactions in supernovae. We can constrain the site and the condition of nucleosynthesis in supernovae from abundances of the p-isotopes. The isotopic anomalies of the p-isotopes of Xe, Cd and Sn are found in acid residues of the Allende carbonaceous chondrite. The anomalies of 84Sr and 144Sm are also found in the Allende FUN inclusions. They are considered to be presolar origin. The anomalies of 196Hg are found, however, their origin still remains enigmatic. The anomaly of Mo isotopic abundances is found in the Sikhote-Alin iron meteorite. The anomaly can be explained by (γ, n) reaction chains of Mo. The further study of the Mo anomaly will give us interesting informations not only about the p-process, but also about the r-process effect on 93Nb, the double β--decay of 96Zr, and the (γ, n) reaction chain of 99Tc.

    DOI: 10.14934/chikyukagaku.26.41

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  • Calibration of Faraday cup efficiency in a multicollector mass spectrometer 査読

    Akio Makishima, Eizo Nakamura

    Chemical Geology   94 ( 2 )   105 - 110   1991年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    Faraday cup efficiencies (FCE's) in the multicollector mass spectrometer were examined with a static multicollcction technique. The relative Faraday cup efficiency (RFCE) was estimated by measurement of Nd-isotopc ratios with five different cup configurations. The application of RFCE correction to the static multicollection technique will increase the reliability of analytical results by eliminating the errors caused by differences in FCE's, and will also enable us to distinguish which Faraday cups are damaged and should be renewed. © 1991, All rights reserved.

    DOI: 10.1016/S0009-2541(10)80022-1

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  • Precise measurement of cerium isotope composition in rock samples 査読

    Akio Makishima, Eizo Nakamura

    Chemical Geology   94 ( 1 )   1 - 11   1991年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    A high-precision analytical method for the measurement of 138Ce/142Ce ratios is reported using static multicollection mass spectrometry. This technique reduced the data acquisition time for 2 hr. for 400 ratios and improved analytical reproducibility to ±0.002% (n = 16) and precision to ±0.002–0.003%. The better precision and reproducibility were established collecting a large ion beam [ 142Ce16O of (2–7 ) · 10−11 A], short data acquisition time and in situ measurement of 18O/16O ratios during the analysis. To reduce the blank effect to the Ce isotope analysis, the chemical procedure for separation of Ce was refined using a small ion-exchange resin bed column (4 cm length × 3 mm diameter) with which the procedural total blank was lowered to 0.04 ng and the recovery yield of Ce from 20 mg BCR-1 was 90%. In order to confirm the reproducibility of this technique including the chemical procedure, six Ce isotope analyses individually separated from the USGS standard BCR-1, were carried out with an analytical reproducibility of ±0.002%. With these analytical precision and reproducibility and normalization to BCR-1 in order to eliminate any inter-laboratory biases, it is now possible to apply the La-Ce isotope system to the terrestrial and extraterrestrial samples combined with other isotope systems, such as Sm-Nd and Rb-Sr. © 1991, All rights reserved.

    DOI: 10.1016/S0009-2541(10)80012-9

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  • ランタンーセリウム法の地球化学 査読

    牧嶋昭夫, 中村栄三, 増田彰正

    火山   36   161 - 175   1991年

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Characterization of surface oxide layer of iron particles for magnetic recording II. Surface oxide layer of further oxidized iron particles in high humidity 査読

    Akio Makishima, Yukihiro Yamamoto, Kohji Watanabe

    Bulletin of the Chemical Society of Japan   63 ( 11 )   3189 - 3192   1990年11月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    The surface oxide layer of additionally oxidized iron particles for magnetic recording in high humidity (90%) and at 60°C was examined by Mossbauer spectrometry. The mechanism of deterioration was concluded to begin with oxidation: the deterioration of the saturation magnetization (Is) of iron particles was caused by a deterioration of the Is of the surface oxide layer; later deterioration was caused by an increase in the amount of the oxide layer. The specific gravity of the surface oxide layer became gradually reduced during the oxidation.

    DOI: 10.1246/bcsj.63.3189

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  • Determination of gallium in pure aluminum by isotope dilution analysis with solvent extraction using inductively coupled plasma mass spectrometry 査読

    Akio Makishima, Isamu Inamoto, Koichi Chiba

    Applied Spectroscopy   44 ( 1 )   91 - 95   1990年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    Isotope dilution analysis with inductively coupled plasma mass spectrometry (ICP-MS) was applied to the determination of gallium in pure aluminum. Furthermore, a solvent extraction procedure was combined with isotope dilution analysis as a preconcentration technique in order to determine ultra-trace levels of gallium with high precision. The accuracy and the precision of isotope dilution analysis using ICP-MS were compared with those of conventional standard addition analysis using ICP-MS. Isotope dilution analysis gave more accurate and precise results than did standard addition analysis. Isotope dilution analysis with solvent extraction made it possible to measure 0.029 μg/g gallium in 99.999% aluminum with analytical errors at less than 3%.

    DOI: 10.1366/0003702904085840

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  • Characterization of the surface oxide layer on iron particles for magnetic recording by Mossbauer spectrometry 査読

    A. Makishima, Y. Yamamoto, K. Watanabe

    Bulletin of the Chemical Society of Japan   63 ( 1 )   147 - 150   1990年

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)  

    The average valency of iron in the oxide layer on iron particles for magnetic recording and the saturation magnetization of the oxide layer were estimated to be 2.8 and 39 emu g-1, respectively, by examining the Debye temperature and the recoilless fraction of oxide layer which were calculated with the Mossbauer parameters.

    DOI: 10.1246/bcsj.63.147

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  • セリウム同位体比測定と年代学への応用における諸問題 査読

    牧嶋 昭夫

    Journal of the Mass Spectrometry Society of Japan   38 ( 4 )   165 - 173   1990年

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(大学,研究機関等紀要)   出版者・発行元:The Mass Spectrometry Society of Japan  

    Tanaka and Masuda1) first applied lanthanum-cerium isotope systematics to geochronology in 1982, using β-decay of 138La. In this systematics, it is necessary to measure cerium isotope ratio (ex. 138Ce/142Ce) with precision better than 0.01% because of long half life and low abundance of 138La. Many studies have been done to improve the precision and accuracy of the Ce isotope analysis. But there are some problems in the analysis, such as long data acquisition time and requirement of large amount of cerium. When the La-Ce systematics is used as a geochemical tracer or in geochronology, β-decay constant of 138La is a very important factor. However, the decay constant is still in controversy so that age dating results using the La-Ce isotope systematics are less convinced compared with those of Sm-Nd and Rb-Sr systematics.<br>In this paper, precise measurements of cerium isotope ratios and geochronological applications are reviewed and their problems are pointed out.

    DOI: 10.5702/massspec.38.165

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  • 138La β-decay constant estimated from geochronological studies 査読

    A. Masuda, H. Shimizu, S. Nakai, A. Makishima, S. Lahti

    Earth and Planetary Science Letters   89 ( 3-4 )   316 - 322   1988年8月

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    掲載種別:研究論文(学術雑誌)  

    LaCe ages are reported for two sets of Finnish pegmatites, Lövböle and Mustikkamäki, and for an Amîtsoq gneiss, Greenland. When λβ 138La value (2.29 × 10-12 yr-1) obtained by radioactivity measurement [1] is used for the chronological calculation, the LaCe ages (2129, 2325, 3271 Myr) evaluated for these rocks are 18-35% older than the SmNd ages for the same samples. To make the LaCe age fit to the SmNd age for the same sample, a new value of (2.77 ± 0.21) × 10-12 yr-1 is evaluated for λβ 138La. In this calculation, the LaCe and SmNd ages reported for a Bushveld gabbro [2] have been also taken into account together with those for the Lövböle pegmatite and the Mustikkamäki pegmatite, while the Amîtsoq gneiss (GGU110999) has been omitted because of the complicated thermal history of this sample. © 1988.

    DOI: 10.1016/0012-821X(88)90119-7

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  • Precise measurement of cerium and lanthanum isotope ratios. 査読

    Makishima Akio, Shimizu Hiroshi, Masuda Akimasa

    Journal of the Mass Spectrometry Society of Japan   35 ( 2 )   64 - 72   1987年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Mass Spectrometry Society of Japan  

    The isotope ratios of cerium and lanthanum are determined precisely by a surface ionization mass spectrometer. 138Ce/142Ce and 140Ce/142Ce ratios for Ce standard solution are 0.0225762± 0.0000014 (2σ) and 7.9471±0.0003 (2σ), normalized to 136Ce/142Ce=0.01688, respectively. 138La/139La ratio is 0.0009025±0.0000005 (2σ). The oxygen isotope ratios in measurements of REE as oxide ions are 0.0003916±0.0000014 (2σ) and 0.002129±0.000010 (2σ) for 17O/16O and 18O/16O. The isotopic abundances (%) of 136Ce, 138Ce, 140Ce and 142Ce are calculated to be 0.1878, 0.2512, 88.433 and 11.128, respectively. The isotopic abundances (%) of 138La and 139La are calculated to be 0.09016 and 99.9098. These isotopic abundances obtained here give the following relation:<br>(138La/142Ce)ATOMIC=0.008173×(La/Ce)WEIGHT.<br>These precise isotopic abundances on Ce and La are fundamental values in a La-Ce geochronometer.

    DOI: 10.5702/massspec.35.64

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書籍等出版物

  • 宇宙岩石入門 : 起源・観測・サンプルリターン

    牧嶋, 昭夫( 担当: 単著 ,  範囲: 全部)

    朝倉書店  2020年7月  ( ISBN:9784254150223

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    総ページ数:171   担当ページ:171   記述言語:日本語 著書種別:学術書

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  • Biochemistry for materials science : catalysts, complexes and proteins 査読

    牧嶋昭夫( 担当: 単著 ,  範囲: 全部)

    Elsevier  2019年  ( ISBN:0128170549

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    総ページ数:329   担当ページ:329   記述言語:英語 著書種別:学術書

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  • Recent topics in advanced materials science 査読

    牧嶋昭夫( 担当: 単著 ,  範囲: 全部)

    Cambridge Scholars Publishing  2019年  ( ISBN:9781527540293

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    総ページ数:510   担当ページ:510   記述言語:英語 著書種別:学術書

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  • Origins of the Earth, Moon and Life: a Multidisciplinary Approach. 査読

    牧嶋昭夫( 担当: 単著 ,  範囲: 全部)

    Elsevier  2017年  ( ISBN:9780128120583

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    総ページ数:255   担当ページ:255   記述言語:英語 著書種別:学術書

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  • Thermal Ionization Mass Spectrometry (TIMS), Silicate Digestion, Separation, Measurement 査読

    牧嶋昭夫( 担当: 単著 ,  範囲: 全部)

    Wiley-VCH  2016年  ( ISBN:9783527340248

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    総ページ数:348   担当ページ:348   記述言語:英語 著書種別:学術書

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MISC

  • 地球惑星物質総合解析システムの構築と応用

    中村栄三, 牧嶋昭夫, 森口拓弥, 小林桂, 田中亮吏, 国広卓也, 北川宙, 太田努, 坂口千恵, 山中正博

    法政大学イオンビーム工学研究所シンポジウム講演予稿集   36th   2017年

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  • 岩石試料中のng g^<-1>レベルのタンタルと、ジルコニウム・ニオブ・ハフニウムの同時定量法の開発

    魯 穎淮, 牧嶋 昭夫, 中村 栄三

    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   236 - 236   2004年9月

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  • Comprehensive geochemical analyses of small amounts (&1t; 100 mg) of extraterrestrial samples for the analytical competition related to the sample return mission MUSES-C

    Nakamura Eizo, Makishima Akio, Moriguti Takuya, Kobayashi Katsura, Sakaguchi Chie, Yokoyama Tetsuya, Tanaka Ryoji, Kuritani Takeshi, Takei Hiroyuki

    The Institute of Space and Astronautical Science report. S.P.   16   49 - 101   2003年3月

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    記述言語:英語   出版者・発行元:宇宙航空研究開発機構  

    We have participated in the analytical competition related to the sample-return mission, MUSES-C of the ISAS, to be launched in May 2003 and returned in summer 2007. In this competition, we have determined major and trace element abundances and isotopes (as many as possible), both for two powdered samples provided by the ISAS and for chondrules separated from Allende meteorite as an additional demonstration of our high-spatial resolution analytical capabilities for fragment samples. 100 mg of each of the competition samples, 1C and 2C, were split into two fractions of approximately 30 and 70 mg for the determinations of elemental abundances and the isotope analyses, respectively. The bulk concentrations of 55 elements in each 30 mg sample were analyzed by quadruple-type ICP-MS and sector-type ICP-MS with analytical uncertainties better than 10 percent (1 sigma). B, Pb, Li, Rb, Sr, Sm and Nd were successively separated from the remaining 70 mg of each of the samples, using a novel integrated, multi-ion exchange column chemistry approach, and then the isotopes of these elements were successfully determined by TIMS with analytical errors similar to those for analyses of terrestrial samples. The Sr, Nd, Re and Os isotopic compositions were also analyzed using the remaining aliquots of the sample solutions for trace element analyses by ICP-MS. The results obtained in this study indicate that 1C and 2C samples are probably ordinary chondrite and the Allende meteorite, respectively. However, extreme W, Ta and Nb enrichments in the 1C were probably caused by contamination during sample preparation. Furthermore, both of the samples were extensively contaminated by B from the borosilicate glass container in which the samples were delivered. Five chondrules were separated from Allende meteorite and then sliced into three pieces using a dicing saw. The center slices were used to petrographically determine the mineral phases, compositionally map these phases by SEM-EDX, and obtain quantitative major and trace element compositions (30 elements) by SEM-EDX and ion microprobe. The two outer slices, for which sample masses were less than 1 mg, were chemically treated to obtain the bulk trace elements and isotope compositions of the chondrules. For the chondrule slices, 24 trace elements and Sr and Nd isotopic compositions were determined with extremely small analytical uncertainties by ICP-MS and TIMS (for Sr and Nd, respectively). Based on the analytical experience, including this competition, we believe that all of the analyses carried out could have been completed within 50 days if we could have concentrated on this project alone during that 50-day period. In this report, we describe the analytical techniques employed for the powdered samples and the chondrules, and we present all of the results obtained during the approximately 3-month period of the analytical competition.

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  • Improvement of mass spectrometer performance for Sr, Nd, Ce and Pb isotope analyses by modification of preamplifiers.

    Makishima,A, Ishikawa,T, Shibata,T, Yoshikawa,M, Nakamura,E

    Technical Report of ISEI (Institute for Study of the Earth's Interior), Okayama University, Ser.B.   11   1 - 18   1993年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • 岩石中の希土類元素定量のための、表面電離型質量分析計Finnigan MAT261の二次電子増倍管のバイアスの評価

    ISEI Report, Ser. B   10   1 - 19   1991年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • 島弧玄武岩の負のセリウム異常の謎 招待

    牧嶋昭夫

    化学と工業   43   1917 - 1918   1990年

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    担当区分:筆頭著者  

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受賞

  • 2023年度、Journal of Analytical Atomic Spectrometry誌における優れた査読者賞

    2024年3月   王立化学会  

    牧嶋昭夫

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  • 2022年度、Journal of Analytical Atomic Spectrometry誌における優れた査読者賞

    2023年3月   王立化学会  

    牧嶋昭夫

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  • 2020年度、Journal of Analytical Atomic Spectrometry誌における優れた査読者賞

    2021年1月   王立化学会  

    牧嶋昭夫

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  • 日本地球化学会・奨励賞

    1994年  

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    受賞国:日本国

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共同研究・競争的資金等の研究

  • HFS元素のp核種同位体比異常に関する研究

    研究課題/領域番号:16K05609  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    牧嶋 昭夫

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    配分額:2210000円 ( 直接経費:1700000円 、 間接経費:510000円 )

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  • 実時間スケールの決定によるマグマダイナミクスの解明

    研究課題/領域番号:23340160  2011年04月 - 2014年03月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    中村 栄三, 牧嶋 昭夫, 田中 亮吏, 小林 桂

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    配分額:19760000円 ( 直接経費:15200000円 、 間接経費:4560000円 )

    本研究は,火山活動におけるマグマダイナミクスに関しての理解を推し進めるため,噴出物から絶対的な時間軸を取り出す手法の開発とその応用を試みた.研究の結果,マルチコレクションICP-MSを用いた新たなU-Th-Ra放射非平衡年代測定法を開発し,その応用として富士火山の噴出物の解析を実施した.また噴出年代を決定するため,新たなK-Ar年代測定法を確立し10万年を切る若い火山岩に対して精密に噴出年代を決定する方法を確立した.巨大珪長質噴火をマグマダイナミクスとして説明するモデルを構築し,公表した.

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  • サブナノグラムのハフニウム同位体比精密測定法の開発によるマントルの化学進化の解明

    研究課題/領域番号:19340162  2007年 - 2010年

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    牧嶋 昭夫, 中村 栄三

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    配分額:14950000円 ( 直接経費:11500000円 、 間接経費:3450000円 )

    岩石記載、主成分元素、微量元素、Hf-Nd-Pb-Sr同位体システマティクスを用いて地球化学的に幌満かんらん岩体を解析した。そこで、幌満かんらん岩帯の成因と進化に関して4つの時間を入れることに成功した。さらに、これまで発見されていなかった低い鉛同位体比をもつ成分を発見した。また、当初の目的であるサブナノグラムのハフニウム同位体比測定法の開発にも成功した。

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  • 10ミクロン以下のジルコンの高確度年代測定法の開発と世界最古の岩石への応用

    研究課題/領域番号:15340192  2003年 - 2005年

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    中村 栄三, 牧嶋 昭夫, 森口 拓弥, 小林 桂

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    配分額:16300000円 ( 直接経費:16300000円 )

    本研究によって、オリンパス社と共に設計・開発を行った高分解能及び汎用二次イオン質量分析計用の超高真空高焦点深度反射顕微鏡システム(PMLopt-1)を活用した高分解能二次イオン質量分析計による年代測定法を確立することが出来た。新規開発を行ったPMLopt-1は、フランス・カメカ社製高分解能及び汎用二次イオン質量分析計(ims-1270、ims-5f)に装備した状態で、設計値である4ミクロンの空間分解能を達成した。このことは、岩石薄片に含まれる10ミクロン以下のジルコンを、高分解能二次イオン質量分析計内で、光学的に確認できることを意味しており、マルチコレクションシステムを活用した、超高空間分解能のジルコン年代測定を可能にする技術的基盤が構築できた。変成岩中に含まれる、変成過程において結晶化したジルコンは、多くの場合その粒径が数10ミクロンから10ミクロンと小さく、さらに含有するウランの濃度が低いため、結果として生ずる娘核種としての鉛の濃度は極めて低い。我々は、岩石薄片試料をそのまま用い、事前にSEMによる主要元素濃度分布の確認及びカソードルミネッセンス法による結晶成長面の確認を実施し、精密な記載のもと年代測定法を実施する方法を確立した。なお分析対象ジルコンは、我々が独自に開発した「Visual Stage」システムを用いて、SEM-高空間分解能二次イオン質量分析計間で位置座標を共有し、極めて効率的に分析を行うことが出来た。この手法を活用し、約60Maの非常に若い形成年代を示す北米コロラドに産するエクロジャイト中のジルコンや、初期地球における大陸地殻形成に重要な役割を果たしたと考えられる、アフリカ・タンザニアの変成岩体・花崗岩体の年代測定を実施し、約2.65Gaという年代を得た。以上の結果は国際誌に投稿し、出版、あるいは出版を待っている状態である。

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  • マントル内部での親鉄・親銅元素の分布と挙同の総合的解明

    研究課題/領域番号:15340188  2003年 - 2005年

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    牧嶋 昭夫, 中村 栄三, 小林 桂

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    配分額:9500000円 ( 直接経費:9500000円 )

    本研究は、マントル内部での親鉄・親銅元素の分布と挙動の総合的解明を目指した。そのために、(1)白金族元素の定量法の開発、(2)白金族元素以外の親鉄・親銅・親石元素の新しい分析法の開発、(3)Re-Os法を用いるための、高感度・高精度かつ簡便な質量分析法の開発の3点を主におこなった。まず、正確さが高い分析から研究をスタートさせるという原点に戻り、試料分解法から検討した。最終的には、約300℃で試料分解が可能な安価な密閉分解容器をあらたに設計・試作した。これのデザインを煮詰め、特許申請を行った。これは、完成すれば、世界中で使われるようになると確信する、画期的なものとなるはずである。この特許申請は公開後、2006年3月現在意見書と補正書を提出しており、特許化は近いと考えている。さらに、四重極型ICP-MSを用いた新しい、Bi、Tl、Inと、Li, Be, Rb, Sr, Y, Cs, Ba, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Th、Uの分析法を開発した。この方法では、Smスパイクを加えて岩石試料を分解しさえすれば、後の希釈を定量的に行なわずに分析できる、ID-IS(同位体希釈-内標準法)を開発し、適用した。試料溶液を0.1ml以下で分析が可能なPseudo-FI法(擬似フローインジェクション法)も開発した。さらに、高分解能型ICP-MS(HR-ICP-MS)を用いて、同一の試料溶液からNa, Mg, Al, P, Ca, V, Mn,Fe, Co, K, Sc, Ni, Cu, ZnやGaが分析できる方法も確立した(revise版をGeostandards and Geoanalytical Research誌に投稿中)。また、HFS元素分析法にも改良を加え、ID法、ID-IS法と四重極型ICP-MS、およびHR-ICP-MSを組み合わせた、B, Ti, Zr, Nb, Mo, Sn, Sb, Hf, Taの分析法も開発した(投稿中)。従来のOs同位体比測定法はN-TIMSで行なわれているが、これと同程度のパフォーマンス(分析精度1%以下、Os必要量1pg以下)を持つ、マルチイオンカウンティング法を用いたMC-ICP-MS分析法を開発した。この方法はOs同位体比測定にN-TIMSが必要なくなるという、画期的なものである(Analytical Chemistry誌、印刷中)。
    分析法の開発に予想以上に手間取り、実際のかんらん岩試料の分析の測定はこれからであるが、分析法がほぼ完成したので応用研究を遂行することは容易である。

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  • 負イオン表面電離型質量分析法によるハフニウム同位体比の高精度測定法の開発と応用

    研究課題/領域番号:15654076  2003年 - 2004年

    日本学術振興会  科学研究費助成事業  萌芽研究

    牧嶋 昭夫, 中村 栄三

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    配分額:3100000円 ( 直接経費:3100000円 )

    本年度は負イオン表面電離型質量分析法によるハフニウム同位体比の高精度測定法の開発と応用の第2年度として、ハフニウム負イオンを生成する条件の検討を行なった。フィラメントに白金を用い、100ngのHfを塗布し、イオン化のアクチベーターとしてバリウム、ランタン、トリウムと硝酸銀を塗布し、フッ化水素酸を最後に塗布してビームを出した。その結果、ハフニウムフッ化物イオンをファラデー検出器で、数ミリボルト1分維持することに成功した。
    また、試料をフッ化水素酸で分解し、四重極型ICPMSを用いる、B-Zr-Hf-Nb-Ta-Sn-Sb-Mo-Wの同時定量法を確立した。
    さらに、この定量用の溶液から、ハフニウムを分離する方法の開発をおこなった。陰イオン交換樹脂AG1X8でチタン・ジルコニウム・ハフニウムに分離し、さらに、U/TEVAという樹脂を用いることによりチタンとジルコニウムを分離することに成功した。この方法により、ハフニウムを80mgの玄武岩試料から回収率87%、ブランク3pg以下で回収することができた。
    さらに、スパイクされた試料に対して、マルチコレクターICP-MSを用いたハフニウム高精度同位体比測定法を開発し、上記の方法で実際の岩石試料からハフニウムを分離し、同位体比を測定する方法を確立した。
    別に、ハフニウムのフッ化錯イオンは樹脂に吸着しにくいために、あらたに、フッ化水素酸なしで、王水で試料を分解することを検討した。この目的のために容器これをデザインし、特許申請をおこなった。
    また、イオン交換樹脂を用いる元素の抽出に関しても新しい方法をデザインし、岡山大学に発明届を提出した。

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  • 火山噴火予知のためのウラン・トリウム放射非平衡年代測定法の開発

    研究課題/領域番号:11554021  1999年 - 2001年

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    中村 栄三, 森口 拓弥, 牧嶋 昭夫

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    配分額:11700000円 ( 直接経費:11700000円 )

    我々は島弧マグマの発生から噴火に至るまでの諸プロセスを定量的に議論するためのツールとして、TIMSを用いた火山岩中のU・Th同位体の精密測定法の開発を行い、それを三宅島火山に適用することで、我々の分析法が定量的議論に対し十分実用可能であることを示した。本分析法は従来法の測定精度を上回るものであり、三宅島以外にも適用することで、さらに火山噴火予知にむけたマグマプロセスの定量的理解が進むことが期待される。しかしながら、以下のような問題点も残った。
    1)二宅島溶岩中の斑晶鉱物一(olivine, clinopyroxene, plagioclase)のU・Th含有量は全岩の1/100しかなく、これを用いて鉱物アイソクロンを描くことは不可能であった。
    2)全岩アイソクロンの年代値のエラーは、分析点数の多いStage2でも11.9±2.1kyrであり、当初の目標であった誤差0.1kyrには及ばなかった。
    1の問題は三宅島溶岩がもともと微量元素の少ないソレアイト質玄武岩であったことに起因している。一方2の問題は2っの原因が考えられる。まずは全岩アイソクロンであるがために、各溶岩間の不均一性が影響している可能性。これは鉱物アイソクロンを用いた結果と比較することで明らかになるはずである。次にアイソクロンの横軸であるU/Th比の変化幅が小さい点である。このような試料で高精度の年代値を出すためには単純にTIMSでのTh同位体比及びU・Th濃度の測定精度を現在より高めるしかない。現在我々が所有しているTIMSでは、本研究で達成した分析精度がほぼ機器の分析限界であり、次世代TIMS(Finnigan TRITON)を用いれば更に分析精度を向上させることが期待できる。これに加え、^<230>Thより更に半減期の短い核種である^<226>Ra(1600年)や^<228>Ra(5.76年)の非平衡を用いればタイムスケールの分解能を高めることができ、より詳細なマグマプロセスの解明につながるに違いない。

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  • 沈み込み帯における元素の挙動に関する実験的・実証的研究

    研究課題/領域番号:08740416  1996年

    日本学術振興会  科学研究費助成事業  奨励研究(A)

    牧嶋 昭夫

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    配分額:1000000円 ( 直接経費:1000000円 )

    本研究では,3GPa-850℃から,8GPa-850℃の範囲で,金カプセルのなかにスラブ相当物質と,マントル相当物質(カンラン石)を封入し,高圧・高温にして,スラブ相当物質を脱水させた.その後,金カプセルを取り出し,外側を洗浄した後,清浄なピンセットでカプセルを破き,スラブ相当物質とマントル相当物質をそれぞれ別々に取り出した.一回の実験で,マントル相当物質約3mgと,スラブ相当物質約6mgが得られた.
    ICP質量分析計(ICP-MS)により,この中の希土類元素,Li,Sr,Rb,Y,Cs,Ba,U,Th,Pbを定量した.実験後のマントル相当物質は,出発物質のスラブ相当物質とマントル相当物質の単純なミキシングとは全く異なる微量元素組成を持つことを見いだした.また,この組成は,カンラン石だけを封入した実験生成物(ブランク実験生成物)の分析結果とも異なっていた。すなわち,スラブ物質は,脱水反応と共に,Cs,Rb,Ba,PbやLREE(La,Ce)が枯渇した。またHREE(Er,Tm,Yb,Lu,Y等)は全く変化しなかった。
    この結果は,沈み込むスラブが,脱水反応によって,より低いLREE/HREE,及び,高いU/Pb比を有することを意味する。これは,沈み込んだスラブが,マントル内に導入された後,海洋島玄武岩の一部であるHIMUマグマの起源物質(海洋島玄武岩や中央海嶺玄武岩のマグマソース全体が示す鉛同位体比の一般的傾向よりも高いU/Pb【μ】を長時間保持していたと考えられるマグマソース)になりうることを示す。
    また,スラブから放出される流体相は、アルカリ金属元素,Pb及びLREEに富み、Y及びHREEに枯渇する特徴を持っていることも意味する。さらに,SIMSによる鉱物の分析の結果から,スラブ側に晶出した garnet は,出発物質に比べHREEに富んでいることも明らかとなった。これらの結果は,スラブ側のHREEはスラブ物質の脱水作用によって晶出する garnet へ分配され,そのために放出される流体相の科学組成が,LREEに富みHREEに枯渇したことを示す。これはすなわち,スラブから放出される流体相の化学組成は,流体とスラブ中の鉱物の間の分配係数に支配されていることを意味している。

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  • 海洋底堆積物の同位体地球化学的キャラクタリゼーション

    研究課題/領域番号:07854029  1995年

    日本学術振興会  科学研究費助成事業  奨励研究(A)

    牧嶋 昭夫

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    配分額:900000円 ( 直接経費:900000円 )

    太平洋の全般にわたるさまざま場所のさまざまな種類の海洋底堆積物(遠洋性粘土,石灰質堆積物,珪藻軟泥,近海性堆積物),及び,これらが続成作用によって固結した四万十帯の頁岩などの,全希土類元素,及び,Sr,U,Th,Pb,Cs,Ta,Ba,Zr,Hf,Beの濃度を,岡山大学・固体地球研究センターのICP-MSを用いて測定した.また,同センターの表面電離型質量分析計を用いて,試料のCe・Nd同位体比を測定した.さらに,ICP-MSを用いた,海洋底堆積物中の,Na,Mg,Al,K,Ca,Sc,Mn,Fe,Co,Ni,Cu,Zn,W,Mo,Sn,Sb,Cd,Tlの濃度測定法を確立した.この方法では,正確さ・再現性,どちらも10%程度で分析が可能となっている.
    海洋底堆積物の微量元素濃度の測定結果から,次のようなことが明らかとなった.(1)Ceを除く希土類元素は相互に相関が高く,また,Caと相関があった.(2)海洋底堆積物にはCe異常があったりなかったりであったが,CeはRb,U,Th,Al,B,Csと相関が見られ,Mnとは無相関であった.これらのことは,Ce濃度は,粘土鉱物などの,大陸起源物質に由来し,これと,海水起源である炭酸塩が混合し,海洋底堆積物の希土類元素パターンを形作ることを意味している.さらに,Ce・Nd同位体比の測定結果と併せると,大陸起源物質(風成塵)は,海水に落ちるとすぐにCe,Ndを海水と同位体交換をすることがあきらかとなった.

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  • 沈み込み帯における希土類元素の挙動の解明

    研究課題/領域番号:06854025  1994年

    日本学術振興会  科学研究費助成事業  奨励研究(A)

    牧嶋 昭夫

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    配分額:1100000円 ( 直接経費:1100000円 )

    私は、沈み込み帯での希土類元素の挙動を解明するために、沈み込み帯の火成活動の結果生じた島弧を代表すると考えられる東北日本の岩石試料(岩手山、船形山、蔵王山、駒ヶ岳、森吉山、寒風山、利尻島)のCe同位体比を測定した。
    また、これらの試料中のインコンパチブル元素(固相よりも液相に移動しやすいウラン、トリウム、リチウム、セシウム、ニオブ、タンタル、バリウム、ジルコニウム、ハフニウム、ベリリウム)を、岡山大学・地球内部研究センターに導入されているICP質量分析計を用いて定量する方法を実用化した。この方法は世界トップレベルの感度を持ちながら、必要試料量が数mgという、極めて少ない試料でも測定が可能であるという特徴を有している。現在、これらの元素の分析をこれらの試料に関して行っているところである。
    さらに、沈み込み帯での希土類元素の挙動を解明する上で、重要な端成分である中央海嶺玄武岩(MORB)の、Ce同位体比によるキャラクタリゼーションをおこなった。その結果、MORBは太平洋・大西洋ともほぼ均一な同位体組成を持ち、その平均は、ε Ce=1.4という値を持っていた。この値は、沈み込み帯での希土類元素の挙動のモデルを作る上で必要不可欠な、重要な値であり、今後世界的にこの値が推奨値として用いられるに違いない。

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  • 地球史におけるマグマ

    研究課題/領域番号:05231103  1993年 - 1995年

    日本学術振興会  科学研究費助成事業  重点領域研究

    大谷 栄治, 佐々木 晶, 丸山 茂徳, 兼岡 一郎, 牧嶋 昭夫, 圦本 尚義

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    配分額:169000000円 ( 直接経費:169000000円 )

    本研究においては、初期地球を含めて地球史の中でマグマの果たした役割に関して初期地球におけるマグマオーシャンの実体を解明すること、マグマの形成による初期地殻の形成過程とマントルの進化過程を明らかにすること、マグマの生成によるマントル内部の不均質と大循環を解明することの三つを目的として研究を行った。
    マグマオーシャンの実体を解明する研究では珪酸塩多成分系(Mg2SiO4-Fe2SiO4,MgO-Al2O3-SiO2系)などの高圧下での溶融関係が実験的に明らかにされ、マグマオーシャンの組成、初期地球で生成したコマチアイトマグマの起源が解明された。またマグマオーシャンの形成にともなう地球核の形成過程を解明するために高圧下における金属鉄と珪酸塩融液間の元素分配の実験的研究が行われた。実験結果とマントルのNiやCoなどの親鉄元素の存在度を比較することによって、下部マントルに達する深いマグマオーシャン中での鉄と珪酸塩の平衡でマントルの親鉄元素存在度が説明できることが明らかになった。
    マグマの形成による初期地殻の形成とマントルの進化に関しては、イスア、ピルパラなど世界各地の始生代の地質体お綿密な調査と採取した岩石試料の化学分析が行われ、コマチアイトマグマの起源が明らかになり、始生代に於いてもプレートテクトニクスが働いていたことが明らかになった。また、始生代の玄武岩マグマを作るマントルが現在に比較して鉄に富んでいたらしいことが明らかになった。
    マグマの生成によるマントル内部の不均質お大循環の研究においては、高温高圧下でのマグマの密度測定が行われ、15-20GPa付近にマグマとダイヤモンドの密度逆転が存在することが実験的に明らかになった。また、マントル内部でのマグマと鉱物間の密度関係が明らかになった。これによるとカンラン石とマグマの密度逆転は予想に反して上部マントルの大部分の深さにおいて生じないようである。マントル内部における水の循環に関する研究が行われ、下部マントルでにおいて存在する高密度含水鉱物であるG相が合成され、単結晶構造解析がなされた。この相は水を15-18%も含みSiが6配位の席を占める点で特異な相であることが明らかになった。

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  • アイスランドの火山岩を用いた地磁気変化史及びマグマ形成史の研究

    研究課題/領域番号:05041059  1993年 - 1994年

    日本学術振興会  科学研究費助成事業  国際学術研究

    河野 長, KRISTJANSSON レオ, 牧嶋 昭夫, 小屋口 剛博, 田中 秀文, LEO Kristjan

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    配分額:9500000円 ( 直接経費:9500000円 )

    平成6年7月に4名の研究者(河野、田中・小屋口、牧島)と研究協力者1名(広井修)がアイスランドにおいて現地調査を行った。また現地側研究者(レオ・クリスチャンソン)は試料採集地点の予備調査を実施、またアイスランド大学の備品(交流消磁器)を貸与するなど、調査の成功に大きく貢献した。調査を主に(1)アイスランド西部、レイクホルト周辺、(2)北部、ストルチャルニール周辺、(3)東部、フリョツダルール、(4)東部、ヨクルダルールの4ヶ所において実施した。
    1.古地磁気資料の採集と予備測定
    上記4ヶ所において、連続露頭を形成している玄武岩溶岩合計264枚から1溶岩当り5本のコアサンプルを採集した。これらはいずれも太陽や磁気コンパスを用いて方向づけした定方位試料である。これらのうち一部は、持参したスピナ-磁力計及び借用した交流消磁装置を用いて現地において磁化を測定した。これにより大まかな正逆のパターンを把握するなど、サンプリングを進める上で大変有益な情報が得られた。
    2.地球化学用試料の採集
    古地磁気試料の採集をした溶岩から各1個の試料を採集した他、スネフェルスネス、ラキ、クラフラ、ヘクラ、ウェストマンヤ-ルなど最近1000年程度の期間内に噴出した比較的シリカの多い溶岩や火砕岩を採集した。これらの岩石は海嶺やホットスポットの噴出物から珪質の地殻が作られるプロセスの証拠を与える可能性がある。これらの試料に対して今後主成分分析、同位体分析などが行われる予定である。
    3.地磁気層序の検討
    古地磁気試料の磁化方位については、現在東大と東工大において測定が進められている。また同じ試料を用いK-Ar年代を決定するために、約50個の試料について現在測定が進められている。このうちカリウムの定量は地震研究所において炎光光度計により、アルゴンの定量は岡山大学地球内部研究センターの質量分析計を用いて共同利用によって実施されている。
    4.古地磁気強度の決定
    過去の磁場強度を求めるためにテリエ法を用いた実験が行われ、約200万年前の地磁気逆転を含むセクションについての結果がまとめられた。この結果はすでに論文として出版された。この結果によると、地磁気の逆転時に磁場は通常より1/4程度に弱くなっている。これはこれまでにすでに知られていた事だか、方向が普通の状態に戻ったあとも強度はしばらく回復しないことが今回の結果から明らかになった。
    5.古地磁気永年変化
    アイスランドも含めて世界中の過去1000万年間の古地磁気データを集め、地球磁場の長期的な変動の特性を検討している。磁場強度データに関しては我々がデータベースを作成し世界中に公開した。また方向データはフランスのグループが作成したデータベースを用いた。これから様々な興味のある統計的性質を引き出すことができ、現在研究を進めている。古地磁気永年変化のモデルはこれまである種の任意性を持った仮定の上に組み立てるのが通例であったが、今回ガウス係数から直接様々な観測量を導き出すことに成功した。この手法はもともとConstable and Parker(1998)によって開発されたものだが、我々はもとの方法とは独立でしかもより一般性をもつ方法を導き出すのに成功したものである。この結果によるとConstable and Parkerのモデルは球上で余りに一様な結果を与え、例えば仮想古地磁気極(VGP)の角度分散が緯度とともに増加することを説明できない。観測値を説明するには四極子項がかなり大きい必要があることが明らかになった。

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  • 中央海嶺玄武岩の新しい同位体地球化学的キャラクタリゼーション

    研究課題/領域番号:05854044  1993年

    日本学術振興会  科学研究費助成事業  奨励研究(A)

    牧嶋 昭夫

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    配分額:900000円 ( 直接経費:900000円 )

    本研究では、太平洋からのN-type MORB試料としてDSDP Hole 420,421,429A,504B,597Bの玄武岩を、また、大西洋からのN-type MORB試料としてHole 395,519,522,562,564の玄武岩のCe・Sr・Nd同位体比を測定し、また、希土類元素を表面電離型質量分析計を用いた同位体希釈法で定量した。
    その結果、次のようなことが明らかとなった。
    1.N-type MORBのセリウム同位体比は、0.0225616から0.0225633という間に入った。これは、epsilonCeで-1.6から-1.0の範囲に相当する。さらに、太平洋と大西洋との間で系統的な差は認められなかった。これは、Tanaka et al.(Nature,333,403-404,1988)によって出されていた、-3.4というMORBの値は例外的なものであることを意味している。また、本研究で得られた平均値、epsilonCe=-1.4が、代表的なMORBのセリウム同位体比であると考えられる。今後、MORBのセリウム同位体比を用いてモデル計算をする場合には、この値を用いるべきである。また、ようやくセリクム同位体比をトレーサーとして用いる基礎ができたともいえる。
    2.用いた試料の多くは、なるべく新鮮な試料を用いたにも関わらず負のセリウム異常を示した。これは、変質した海洋底玄武岩には、従来考えられているよりもはるかに普遍的に負のセリウム異常が存在していることを意味している。そのため、変質した玄武岩の負のセリウム異常が島弧火成岩の負のセリウム異常の一因となっているという仮説は、かなり信憑性が高いと考えられ、今後、セリウム同位体比と組み合わせた研究によって、島弧での物質移動の研究が飛躍的に進歩すると期待される。

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  • 地球史初期における始源地殻の成因

    研究課題/領域番号:02044100  1990年

    日本学術振興会  科学研究費助成事業  国際学術研究

    秋本 俊一, ロバート・ヒル ヒル, イアン・キャンベル キヤンベル, 牧嶋 昭夫, 中村 栄三, 加々美 寛雄

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    配分額:4300000円 ( 直接経費:4300000円 )

    地球史における初期大陸地殻と花崗岩類の成因を明らかにするために、岡山大学地球内部センタ-から3名を西オ-ストラリアのノ-スマン・カルグ-リ-地域に派遣し、オ-ストラリア国立大学地球科学研究所(ANU)の協力を得て、約27億年前に形成されたと考えられている花崗岩、グリ-ンスト-ン、及び堆積岩類の採集を行った。その後、オ-ストラリア国立大学に移動し、研究代表者の秋本を加えて、採集した岩石試料から鉱物を分離した。それらの鉱物の中のジルコンをANUの高分解能二次イオン質量分析計(SHRIMP)を用いて鉱物ごとの微小領域ウラン・鉛年代測定を行った。その結果、この地域の花崗岩類は2665±8Maと2686±9Maの二つの異なる形年代を示すグル-プからなることが明らかになった。一方、ジルコンの核の年代は30億年から35億年を示し、これらの花崗岩類が既に存在していた大陸地殻の再溶融によって形成されたことを物語っている。既にANUのグル-プによって行われていたこれらの花崗岩類の主要・微量元素組成は、形成年代によって異なり、古いタイプは若いタイプに比べてより深い地殻の溶融によって形成されたことが明らかとなった。これらの花崗岩類に隣接するグリ-ンスト-ン中のジルコンの年代測定結果は古いタイプの花崗岩類ものよりも約1500万年古い年代を示した。以上の結果と当時の予想される地温勾配から、玄武岩マグマの熱伝導によって、既に存在していた大陸地殻が溶融して二つの異なる花崗マグマが形成されたものと考えられた。
    オ-ストラリアで採集された岩石試料と分離された鉱物は、表面電離型質量分析計を用いた同位体比測定と希土類元素の定量を行うために岡山大学地球内部研究センタ-に送られた。これらの試料の一部は現在分析が進められている。分離された鉱物のうちで緑簾石、チタン石、燐灰石の希土類元素含有量とセリウム及びネオジム同位体比測定は終了した。その他の試料については、微量元素の定量、セリウム、ネオジム、ストロンチウム、鉛、ホウ素同位体比測定が現在行われているところである。地球内部研究センタ-では、本研究期間中に新たに、鉛同位体比測定法、ストロンチウム及びネオジム同位体比測定法を確立し、セリウム及びホウ素同位体比測定法に関しては世界で最も精度の高い分析法を独自に開発した。
    平成3年2月から3月にかけて2週間、ANUからイアン・キャンベル、ロバ-ト・ヒル両博士を岡山大学地球内部研究センタ-に招へいした。この期間中、彼らは当センタ-の分析技術を視察し、研究の現状を把握した。更に、この共同研究のANU側の研究状況を我々が理解するために以下の五つの講演を行った。(1)The fluid dynamics of magma chamber(Ian Camobell),(2)Mantle plumes and flood basalts(Ian Campbell),(3)Evolution of a Late Archean greenstone belt,Yilgarn craton,Western Australia(Robert Hill),(4)Mantle plumes and continental tectonics(Robert Hill)(5)The evolution of the Stracture of the Earth's mantle(Ian Campbell)。また、これまでの結果をもとに、今までの問題を議論・検討し、今後の研究方針として次のような同意が得られた。(1)鉱物のランタン・セリウム系のアイソクロンを求め、他の年代測定法によって求められた年代と比較することによってランタン・138の壊変定数を決定する。(2)年代測定結果より、花崗岩マグマ形成における熱収支を時間の関数として求める。(3)鉛、ホウ素、セリウム同位体比を用いて花崗岩類とグリ-ンスト-ンの起源物質を明らかにする。(4)これらの同位体を用いることにより、マントル起源と始源地殻起源の違いが明確に出来る。(5)以上の事柄をもとに、始生代における花崗岩類の成因と大陸地殻の形成過程を議論する。(6)以上で得られた地球化学的モデルに対して物理的制約を与えるために地温勾配とマントルにおける超高圧鉱物物性及び流体力学的実験によってマントル中での物質と熱の移動、それに伴われるマントル物質の溶融等を推定し、当時のマントル及び地殻のダイナミクスを議論する。

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