研究者詳細 - 田中　亮吏

論文 - 田中　亮吏

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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

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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The influence of aeolian dust in non-allophanic Andosols on Yakushima Island 査読

Tetsuya Eguchi, Ryoji Tanaka, Yuji Maejima, Kenji Tamura

SOIL SCIENCE AND PLANT NUTRITION 58 ( 2 ) 191 - 199 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

The oxygen isotope (delta O-18) composition of quartz and the d((060)) values of clay minerals were determined from four pedons of non-allophanic Andosols derived mainly from the Holocene volcanic ash on Yakushima Island. These soils contained considerable amounts of aerosol-sized (1-10 mu m) and coarse (>53 mu m) quartz. The delta O-18 values for the aerosol-sized quartz ranged from 14.7 parts per thousand to 17.4 parts per thousand, which was comparable to or slightly lower than known values for loess-derived Red and Yellow soils on Tanegashima Island located approximately 20 km east of Yakushima Island. The abundance and delta O-18 values of the aerosol-sized quartz indicated that non-allophanic Andosols on Yakushima Island were strongly influenced by aeolian dust. However, the presence of coarse quartz implied that granite-derived materials were also incorporated into non-allophanic Andosols. X-ray diffraction patterns for most clay minerals showed two broad peaks around 0.154 and 0.150 nm, respectively. The d((060)) values confirmed that 2:1-2:1:1 clay minerals consisted of dioctahedral and trioctahedral clay minerals. Since aeolian dust contains little or no coarse quartz and trioctahedral clay minerals, the abundance of coarse quartz and trioctahedral minerals confirmed that the occurrence of non-allophanic Andosols on Yakushima was influenced by biotite-granite, in addition to aeolian dust.

DOI： 10.1080/00380768.2012.672926

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「はやぶさ」回収試料の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 33 ( 12 ) 681 - 686 2012年

NORTHWEST AFRICA 6704: A UNIQUE CUMULATE PERMAFIC ACHONDRITE CONTAINING SODIC FELDSPAR, AWARUITE AND "FLUID" INCLUSIONS, WITH AN OXYGEN ISOTOPIC COMPOSITION IN THE ACAPULCOITE-LODRANITE FIELD 査読

A. J. Irving, R. Tanaka, A. Steele, S. M. Kuehner, T. E. Bunch, J. H. Wittke, G. M. Hupe

METEORITICS & PLANETARY SCIENCE 46 A108 - A108 2011年7月

Sr-Nd-Hf-Pb isotopic characteristics of North-Western and Southern Ethiopian lithospheric mantle 査読

A. Melesse, T. Kunihiro, T. Ota, R. Tanaka, T. Moriguti, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 74 ( 12 ) A697 - A697 2010年6月

Precise Elemental and Isotopic Analyses in Silicate Samples Employing ICP-MS: Application of Hydrofluoric Acid Solution and Analytical Techniques 査読

Akio Makishima, Ryoji Tanaka, Eizo Nakamura

ANALYTICAL SCIENCES 25 ( 10 ) 1181 - 1187 2009年10月

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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CONFIRMATION OF epsilon(CR)-C-54-Delta O-17 CORRELATION IN BULK CARBONACEOUS CHONDRITES AND ITS ASTROPHYSICAL SIGNIFICANCE 査読

Qing-Zhu Yin, K. Yamashita, A. Yamakawa, R. Tanaka, E. Nakamura, A. N. Krot, B. S. Meyer

METEORITICS & PLANETARY SCIENCE 44 A224 - A224 2009年7月

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

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

GEOCHEMICAL JOURNAL 43 ( 3 ) 207 - 216 2009年

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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Lead isotope systematics of olivine-hosted melt inclusions from Hawaiian lavas 査読

R. Tanaka, P. A. Sakyi, K. Kobayashi, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 72 ( 12 ) A930 - A930 2008年7月

aEvolution of the Southern Ethiopian Rift System: Constrained from geochronological and geochemical data of mafic lavas of Amaro and Yabello areas 査読

D. B. Tesfaye, R. Tanaka, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 72 ( 12 ) A942 - A942 2008年7月

Dislocation microstructures in naturally deformed olivine crystals from Hawaiian lavase 査読

P. A. Sakyi, R. Tanaka, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 72 ( 12 ) A819 - A819 2008年7月

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

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

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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Forsterite-rich and Ca-poor olivine phenocryst crystallized by polybaric melting in a subduction zone 査読

R. Tanaka, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 71 ( 15 ) A998 - A998 2007年8月

Recent and episodic addition to the Hawaiian plume activity 査読

R. Tanaka, A. Makishima, E. Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 70 ( 18 ) A636 - A636 2006年8月

Boron isotopic constraints on the source of Hawaiian shield lavas 査読

R Tanaka, E Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 69 ( 13 ) 3385 - 3399 2005年7月

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

Boron isotopic compositions of lavas from three representative Hawaiian shield volcanoes (Kilauea, Mauna Loa, and Koolau) were analyzed by thermal ionization mass spectrometry. The boron isotopic composition of each sample was analyzed twice, once with and once without acid leaching to evaluate the effect of posteruptive boron contamination. Our acid-leaching procedure dissolved glass, olivine, secondary zeolite, and adsorbed boron; this dissolved boron was completely removed from the residue, which was comprised of plagioclase, pyroxenes, and newly formed amorphous silica. We confirmed that an appropriate acid-leaching process can eliminate adsorbed and incorporated boron contamination from all submarine samples without modifying the original B-11/B-10 ratio. On the other hand, when the sample was weathered, i.e., the olivine had an iddingsite rim, B-11/B-10 of the acid-resistant minerals are also modified, thus it is impossible to get the preeruptive B-11/B-10 value from the weathered samples. Through this elimination and evaluation procedure of posteruptive contamination, preeruptive delta(11)B values for the shield lavas are -4.5 to -5.4 parts per thousand for Koolau (N = 8), -3.6 to -4.6 parts per thousand, for Kilauea (N = 11), and -3.0 to -3.8 parts per thousand for Mauna Loa (N = 6).
Historical Kilauea lavas show a systematic temporal trend for B content and Nb/B coupled with other radiogenic isotopic ratios and trace element ratios, at constant delta(11)B, indicating little or no assimilation of crustal materials in these lavas. Uncorrelated B content and delta(11)B in Koolau and Mauna Loa lavas may also indicate little or no effect of crustal assimilation in these lavas. The source of KEA-component (identical to the so-called Kea end member in Hawaiian lavas) of the Hawaiian source mantle, represented by Kilauea, should be derived from lower part of subducted oceanic crust or refractory peridotite in the recycled subducted stab. The systematic trend from Kilauea to Koolau-decreasing delta(11)B coupled with decreasing epsilon Nd as well as increasing Sr-87/Sr-86 and Pb-206/Pb-204-is consistent with involvement of subducted sediment components in the EMK(enriched Makapuu)-component, represented by Makapuu-stage of Koolau lavas. Copyright (C) 2005 Elsevier Ltd.

DOI： 10.1016/j.gca.2005.03.009

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Lithium, boron, and lead isotope systematics of glass inclusions in olivines from Hawaiian lavas: evidence for recycled components in the Hawaiian plume 査読

K Kobayashi, R Tanaka, T Moriguti, K Shimizu, E Nakamura

CHEMICAL GEOLOGY 212 ( 1-2 ) 143 - 161 2004年11月

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

Lithium (Li), boron (B), and lead (Pb) isotopic compositions of glass inclusions in olivine phenocrysts from Hawaiian lavas, (Kilauea Iki, Mauna Loa, and Koolau volcano) were measured by high mass resolution ion probe to search for possible signatures of recycled materials in the Hawaiian plume. In order to measure the isotopic compositions, a set of synthetic glass standards with matrices similar to those of the target glass inclusions was prepared. Isotopic variations among these synthetic standards were produced by additions of spikes, and their isotopic compositions were determined by TIMS. Using this set of standards, correction factors for instrumental mass fractionation for Li, B, and Pb isotope measurement were determined with internal precisions of <1.2%, <1.6%, and <0.8% (2sigma) uncertainties for Li, B, and Pb, respectively.
Twenty-eight glass inclusions were measured after homogenization to eliminate dendritic crystals. These glass inclusions showed isotopic variations from -10.2% to +8.4% for delta(7)Li, from -10.5% to +5.2% for delta(11)B, from 0.7994 to 0.8909 for (207) Pb/Ph-206, and from 1.989 to 2.139 for Pb-208/Pb-206, which are considerably larger than those for whole rocks. This suggests that the Hawaiian lavas are mixtures of melts derived from isotopically distinct sources, and that glass inclusions better preserve information regarding source heterogeneity than do whole rocks. In particular, significantly low delta(7)Li and delta(11)B values for the Mauna Loa and Koolau samples indicate an isotopically "light" Li and B source, perhaps containing recycled materials that experienced dehydration during subduction. The extremely low Pb isotope signature, which corresponds to HIMU, also suggests some contribution from recycled materials to the generation of the Hawaiian magma. Our results suggest that recycled materials, which experienced near-surface alteration and then dehydration during subduction, played an important role in creating geochemical heterogeneity in the Hawaiian lavas. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chemgeo.2004.08.050

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Boron isotopic composition of Hawaiian shield lavas 査読

R Tanaka, E Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 68 ( 11 ) A46 - A46 2004年6月

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

R Tanaka, A Makishima, H Kitagawa, E Nakamura

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY 18 ( 12 ) 1458 - 1463 2003年12月

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

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&DEG;C in an ultrasonic-bath (denoted as the ultrasonic method) and at 205&DEG;C using a TFE Teflon(R) 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 Al-addition 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.

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

R Tanaka, H Kitagawa, A Makishima, E Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 67 ( 18 ) A475 - A475 2003年9月

Evolution of an isotopically depleted mantle xenolith from salt lake crater, Hawaii 査読

E Nakamura, C Sakaguchi, R Tanaka, T Moriguti, Kushiro, I

GEOCHIMICA ET COSMOCHIMICA ACTA 67 ( 18 ) A324 - A324 2003年9月

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