研究者詳細 - 牧嶋　昭夫

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

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

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

Precise measurement of cerium isotope composition in rock samples 査読

Akio Makishima, Eizo Nakamura

Chemical Geology 94 ( 1 ) 1 - 11 1991年

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

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

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

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

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

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

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

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

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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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

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

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

「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

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

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

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

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

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

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

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.

DOI： 10.1016/j.chemgeo.2010.03.018

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

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

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

ユレイライトのMn-Cr年代測定

山川茜, 山下勝行, 牧嶋昭夫, 中村栄三

日本地球化学会年会要旨集 57 270 - 270 2010年

出版者・発行元：一般社団法人日本地球化学会

ユレイライトは始原的な特徴を持つ、ユニークなエコンドライトである。しかし、ユレイライトはK, Rb, U, Th, 希土類元素に乏しいため、その精密な年代測定は困難である。本研究では、新たに開発された分析法を用いて、モノミクトユレイライトのMn-Cr年代測定を行った。本研究では2つのユレイライト(NWA 766とNWA 1241)を段階的に分解し、それぞれのアイソクロンを求めた。その結果、ユレイライト母天体の形成が約4565Maには始まり、少なくとも数百万年は続いたことが明らかになった。

DOI： 10.14862/geochemproc.57.0.270.0

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