研究者詳細 - 中村　栄三

MISC - 中村　栄三

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Geochemical Evolution of Koolau Volcano, Hawaii. AGU Monograph "Evolution of Hawaiian Volcanoes",pp.? ,311-332, 2002.

Tanaka, R, Nakamura, E, Takahashi, E

AGU Monograph of "Evolution of Hawaiian Volcanoes" 2002年

Geochemical Evolution of Akagi Volcano, Northeast Japan: Implications for Interaction between Island Arc Magma and Lower Crust, and Generation of Isotopically various Magmas

Kobayashi, K, Nakamura, E

J. Petrol. 2001年

Formation and suppression of AlF3 during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS and ID-TIMS

Takei, H, Yokoyama, T, Makishima, A, Nakamura, E

Proc. Japan Acad. 2001年

Precise analysis of 234U/238U ratio using UO2+ ion with thermal ionization mass spectrometry for natural samples

Yokoyama, T, Makishima, A, Nakamura, E

Chem. Geol. 2001年

Boron isotope geochemistry of metasedimentary rocks and tourmalines in the subduction-zone metamorphism

Nakano, T, Nakamura, E

Phys. Earth Planet. Interiors 2001年

A new group separation method of ruthenium, palladium, rhenium, osmium, iridium and platinum using their bromocomplexes and novel anion exchange resin

Makishima, A. Nakanishi, M, Nakamura, E

Anal. Chem. 2001年

Determination of total sulfer at mg g-1 levels in geological materials by oxdation of sulfer into sulfate with in situ generation of bromine using isotope dilution high resolution ICPMS

Anal. Chem. 2001年

Partitioning of major elements between garnet-structured minerals and silicate melt at pressure of 3-15 GPa

Toshihiro Suzuki, Masaki Akaogi, Eizo Nakamura

Physics of the Earth and Planetary Interiors 120 ( 1 ) 79 - 92 2000年6月

記述言語：英語

High-pressure melting experiments on primitive mantle composition material (PM1) and thoreiitic basalt (JB2) were performed from 3 to 15 GPa, and garnet (majorite)/silicate melt partition coefficients, D, were measured for major elements. In the case of PM1, garnet was the liquidus phase only at around 15 GPa, where the partitioning experiments were performed. Although experimental time of PM1 was changed from 10 to 120 min, no obvious change was found in the observed D values of major elements. The liquidus phase of JB2 was garnet under the present experimental conditions. With increase in pressure, an obvious increase in D(Na) and decrease in D(Ti) were found in JB2, but D values of the other elements showed no significant pressure dependence. The observed D values of PM1 and JB2 were compared in partition coefficient (PC)-ionic results (IR) diagram. Although the absolute D values were different, D profiles of PM1 and JB2 at 15 GPa resembled each other. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0031-9201(00)00144-8

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Constraints on HIMU and EM by Sr and Nd isotopes re-examined

Takeshi Hanyu, Eizo Nakamura

Earth, Planets and Space 52 ( 1 ) 61 - 70 2000年

記述言語：英語出版者・発行元：Springer Berlin

Sr and Nd isotopes together with trace elements for ocean island basalts in the Polynesian region have been analyzed in order to investigate the origin of the HIMU and EM sources. Both whole rocks and cpx phenocrysts were analyzed for isotopic composition. Cpx samples from HIMU islands show quite uniform 87Sr/86Sr ratios (~0.70274), while leached and unleached whole rock samples show variable and higher 87Sr/86Sr than those of cpx samples. These results suggest that even leached whole rock samples have been affected by secondary contaminations of sea water. On the other hand, cpx preserves a pristine isotopic signature with minimal secondary effects. Using only the cpx analyses, HIMU form a vertical linear trend in the Sr-Nd isotope diagram with small variation in ε(Nd) (+3.3~+5.5) and constant 87Sr/86Sr. This trend is explained by a mixing of the HIMU end-member and the MORB source. Since ε(Nd) of the HIMU end-member is constrained to be less than +3.3, the HIMU source should include former sediment added to oceanic crust. To explain the vertical nature of the mixing trend, the HIMU end-member should have similar Rb/Sr to the MORB source, or much lower Sr/Nd ratio than the MORB source, which favors a mixing model between extensively dehydrated oceanic crust and sediment as the HIMU source. The correlation between ε(Nd) and trace element ratios such as Pb/Ta also supports the model.

DOI： 10.1186/BF03351614

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Constraints on HIMU and EM by Sr and Nd isotopes re-examined

Hanyu, T, Nakamura, E

Earth, Planets and Space 2000年

Comprehensive geochemical analyses of small amounts (<100mg) of extraterrestrial samples for the analytical competition related to the sample-return mission, MUSES-C. .

Nakamura, E, Makishima, A, Moriguti, T, Kobayashi, K, Sakaguchi, C, Yokoyama, T, Tanaka, R, Kuritani, T, Takei, H

Report for the Analytical Competition for Extraterrestrial Materials required by Institute for Space and Astronautical Science 2000年

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

Akio Makishima, Eizo Nakamura

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

記述言語：英語出版者・発行元：Royal Soc of Chemistry

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 &lt
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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Geochemical evolution of the Horoman peridotite complex: Implications for melt extraction, metasomatism and compositional layering in the mantle

Yoshikawa, M, Nakamura, E

J. Geophys. Res. 2000年

Timing of magmatic and metamorphic events in the Jijal complex of the Kohistan arc deduce from Sm-Nd dating on mafic granulites

Yamamoto, H, Nakamura, E

J. Geol. Soc. London 2000年

Determination of titanium at micro-g/g levels in few milligram silicate materials by Isotope dilution high resolution inductively coupled plasma mass spectrometry with flow injection (ID-FI-HR-ICP-MS)

Makishima, A, Nakamura, E

J. Anal. Atomic Spectrom. 2000年

Partitioning of major elements between garnet-structured minerals and silicate melt at pressure of 3-15 GPa

Suzuki, T, Akaogi, M, Nakamura, E

Phys. Earth Planet. Interiors 2000年

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

Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

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

記述言語：英語

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 micro-g /g levels in geological materials by ID-FI-ICP-MS

Makishima, A, Nakamura, E

Geostand. Newslett. 1999年

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

Yokoyama, T, Makishima, A, Nakamura, E

Chemical Geology 1999年

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

Tetsuya Yokoyama, Akio Makishima, Eizo Nakamura

Analytical Chemistry 71 ( 1 ) 135 - 141 1999年

記述言語：英語出版者・発行元：American Chemical Society

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 &lt
19 pg for Th and &lt
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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