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Volume 42 (2008)
- Issue 4 Pages 113-
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- Issue 2 Pages 43-
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Volume 42, Issue 4
Displaying 1-11 of 11 articles from this issue
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Memorials
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Ei-ichiro TANOUE2008 Volume 42 Issue 4 Pages i-ii
Published: 2008
Released on J-STAGE: February 04, 2017
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Akira UYEDA2008 Volume 42 Issue 4 Pages iii-iv
Published: 2008
Released on J-STAGE: February 04, 2017
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Genki INOUE2008 Volume 42 Issue 4 Pages v-vii
Published: 2008
Released on J-STAGE: February 04, 2017
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Special Section “Geochemistry of Atmospheric Aerozols”
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Yoshiro NISHIO, Masaharu TANIMIZU, Yoshio TAKAHASHI2008 Volume 42 Issue 4 Pages 113-114
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSThis special issue of "Chikyu Kagaku" grew out of a session "Analytical Advance in Geochemistry" in 2008 Geochemical Society of Japan (GSJ) annual meeting held in Okayama University. The development of analytical technique is an engine of geochemistry. To fire it up, several non-GSJ speakers who are in the front lines of analytical development were invited to the session. In this special issue, three papers (Kawamura, 2008; Xue and Kanzaki, 2008; Kawabata, 2008) are written by the invited speakers. Also, this special session aims to introduce solid advancement of analytical technique. Thus, various research topics (mass-spectrometry, NMR, synchrotron μ-XRF, and molecular dynamics) are covered in this special issue. We wish that this special issue can contribute to understanding of mechanism of the state-of-the art methods and to their spread in the geochemical field. In closing, the editors extend our warmest thanks to all of the authors who not only submitted papers for this volume,but also served as reviewers.View full abstractDownload PDF (310K)
Reviews
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Katsuyuki KAWAMURA2008 Volume 42 Issue 4 Pages 115-132
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSUnderstanding of nano-structure and nano-properties of materials constituting the earth's crust and the hydrosphere is essentially needed to elucidate transportation of material in the earth's surface environment and to apply the materials for engineering uses. Molecular simulation methods are ones of the most predominant methods for this purpose. The molecular dynamics method, one of molecular simulation methods, outlined briefly first, and the interatomic interaction model, which is essential to perform molecular simulations, are described. As an application of the methods, we show the molecular dynamics calculation on clay mineral-water systems, such as swelling by water, wetting on clay surfaces, local properties of water and solutions in the vicinity of clay surfaces, etc.View full abstractDownload PDF (2551K) -
Xianyu XUE, Masami KANZAKI2008 Volume 42 Issue 4 Pages 133-155
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSKnowledge of the atomic structures of Earth's materials is indispensible for the understanding/modeling of macroscopic geochemical processes. Solid-state NMR spectroscopy offers a rich variety of advanced multi-nuclear, multi-dimensional techniques that can provide not only quantitative information about local structures around different elements (isotopes), but also direct information concerning atomic connectivities. Recently, we have applied some of these techniques to unravel the structures of (1) high-pressure hydrous minerals in the MgO-SiO2-H2O and Al2O3-SiO2-H2O systems (e.g. phase egg, δ-AlOOH, phase D, superhydrous B), which represent potential water reservoirs in the Earth's mantle, and (2) hydrous (alumino) silicate glasses (quenched melts), which serve as analogs for natural magmas. For the hydrous minerals, the states of Si-Al and Si-Mg order/disorder among octahedral sites and hydrogen distribution and hydrogen-bonding distances were clearly revealed. Such information would have been difficult to obtain by any other single technique. For the hydrous aluminosilicate melts, advanced NMR techniques provided the key information needed to end a long-standing controversy concerning the water dissolution mechanisms. Some of these results are summarized here to demonstrate the usefulness and wonder of advanced solid-state NMR spectroscopy.View full abstractDownload PDF (2698K) -
Katsuhiko KAWABATA2008 Volume 42 Issue 4 Pages 157-163
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSInductively coupled plasma mass spectrometry (ICP-MS) has been an indispensable tool for analysis of metals at ultra trace level. Looking back upon the history of ICP-MS, how to increase the sensitivity with lower background and how to eliminate interferences have been major research themes. Various techniques have been developed to eliminate interferences, and the most popular technique for a time being is collision cell and reaction cell technologies. These two techniques are similar, but they are in fact completely different in terms of the way of interference elimination. In addition, there is another important differentiation in terms of elimination of by-product ions generated in the cell. In this paper, a principle of collision and reaction cell technologies will be described.View full abstractDownload PDF (842K)
Original papers
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Yuko SUGIYAMA, Patrick G. HATCHER, Osamu MITAMURA, Toshiya KATANO, Tet ...2008 Volume 42 Issue 4 Pages 165-177
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSLake Baikal, located on the north-eastern borders of Central Asia, is the deepest (maximum depth 1,700 m) and one of the largest lakes in the world. To elucidate the chemical composition of dissolved organic matter (DOM) in the Lake Baikal, we applied high resolution fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to the lake water samples. Water samples were taken at the deepest point of Lake Baikal and its inflowing Barguzin River mouth on August 2005. The sample water was filtrated on board and DOM was extracted using C 18 solid-phase extraction disks (Kim et al., 2003^a). The extracted samples on the disks were analyzed by a 9.4-T FT-ICR mass spectrometer at the National High Magnetic Field Laboratory (Tallahassee, FL, USA) in negative ionization mode with a needle voltage of -2.0 kV. From the FT-ICR mass analysis, 3511, 2862 and 2191 peaks were detected (S/N>3) in river and 5 m- and 945 m- depth lake water samples, and more than 80% of the peaks were assigned within ± 1.0 ppm error. Using van Krevelen Diagrams (van Krevelen, 1950), we found that the main component of L. Baikal DOM was allochthonous lignin-like organic molecule, and that autochthonous lipid- and protein-like molecules were also found in surface water.View full abstractDownload PDF (1454K) -
Keiko SATO, Hidenori KUMAGAI, Hajimu TAMURA, Hiroshi KAWABATA2008 Volume 42 Issue 4 Pages 179-199
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSLaser fusion measurement for a single grain of phenocryst or of in-situ measurement of less-abundant minerals found on thin sections is established for K-Ar dating method. For such kind of samples, Ar-Ar dating is applied widely to obtain radiometric ages because the Ar-Ar method is independent of the site difference between K and Ar in the specimen. However, Ar-Ar dating raises at least two difficulties: 1) the method requires a control area to treat radioactive samples that were irradiated with neutrons in a nuclear reactor before the analysis to produce 39Ar from 39K; 2) quantities of nuclides produced by irradiation mask information about the original isotope ratios in rock and mineral samples. Consequently, detailed correction using the initial noble gas isotope ratio is inapplicable, which poses a serious problem, especially for recent samples or samples with low K concentrations, which are expected to include minute amounts of radiogenic Ar. In these cases, large uncertainty is brought to ages useless by the masking of the original isotope ratio. Herein, we report an un-irradiated and un-spiked laser fusion K-Ar dating method, with which we can analyze both Ar and K for the identical grains or positions on a thin section. This is mainly attributable to the following protocols: 1) K measurement following/after laser fusion Ar measurement applied to the retrieved single mineral grain itself; and 2) in-situ laser fusion Ar measurement applying to the epoxy resin mounted grain, where its K-content measured using EPMA. This method is expected to enable acquisition of precise radiometric ages of young lavas or of low K samples having a low 40Ar/36Ar ratio.View full abstractDownload PDF (2608K) -
Teruyuki MARUOKA2008 Volume 42 Issue 4 Pages 201-216
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSContinuous flow isotope ratio mass spectrometry (CF-IRMS) has significant advantages over the classic off-line methods in terms of high sensitivity and short analytical time. These advantages play an important role in expansion of its application to many scientific fields. However, the precision for isotope analysis by CF-IRMS has been believed to be lower than that of the off-line methods. In this study, a detailed evaluation of the performance of CF-IRMS for carbon and sulfur isotope analysis for solid materials is reported. High-precision, similar to the offline methods (within ±0.1 ‰), was achieved for carbon isotope analyses after the following improvements: (1) stabilization of room temperature (within ±0.1℃ in 10 minutes). (2) minimization of the non-linearity effect (i.e., pressure effect for instrumental isotopic fracionation) by the adjustment to a proper ion-repeller voltage. (3) reduction of background gas by using pre-heated tin capsules and high-grade helium and oxygen. In addition to the improvements mentioned above, high-precision isotope analyses (within ±0.1 ‰) of sulfur in solid materials require the following improvements: (1) stabilization of reference gas pressure by installing a centrifuge fan to properly exhaust the reference gas. (2) equilibrium of oxygen isotopes using a tube filled with quartz wool. (3) minimization of a memory effect by using polytetrafluoroethylene (PTFE) tubes and a PTFE gas-chromatography column. (4) use of V2O5 with a low sulfur content.View full abstractDownload PDF (1952K) -
Tetsu KOGISO, Katsuhiko SUZUKI, Toshihiro SUZUKI, Kentaro UESUGI, Akih ...2008 Volume 42 Issue 4 Pages 217-228
Published: 2008
Released on J-STAGE: February 04, 2017
JOURNAL FREE ACCESSSynchrotron radiation X-ray is characterized by its ultra-high brightness, which is suitable for non-destructive analysis of rock samples at micrometer scale. We have developed new procedures for non-destructively detecting tiny secondary minerals from the inside of rock samples with subtraction imaging and microbeam X-ray fluorescence (μ-XRF) techniques. The subtraction imaging is a method for element mapping through a rock sample, which is deduced from the difference between two X-ray absorption images taken at energies slightly above and below absorption-edge energy of a target element. The effective spatial resolution is 〜5 to 20 μm for platinum-group elements. The μ-XRF is X-ray fluorescent analysis with an X-ray beam of submicrometer spot size, which is made with a Fresnel zone plate (FZP) optics. The μ-XRF can detect many elements simultaneously with sub-micrometer spatial resolution. With the subtraction imaging and μ-XRF, we have succeeded in non-destructively detecting small grains of platinum-group minerals from a geological reference material and a natural peridotite sample.View full abstractDownload PDF (1714K)
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