GEOCHEMICAL JOURNAL
Online ISSN : 1880-5973
Print ISSN : 0016-7002
ISSN-L : 0016-7002
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Volume 19, Issue 4
Displaying 1-10 of 10 articles from this issue
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  • Metallic element contents of biotite collected along the Nishiki river, Southwest Japan—Heavy metal concentration to caly minerals in aqueous solutions. II.
    Setsuo Takeno, Asao Minami, Ryuji Kitagawa
    1985 Volume 19 Issue 4 Pages 181-192
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.181
    JOURNAL FREE ACCESS
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    Metallic element contents of biotite collected along the Nishiki river, Southwest Japan, were investigated by means of atomic absorption spectrophotometry and the results obtained were examined from mineralogical and statistical view points. Biotite in the district is commonly altered to vermiculite and to lesser extent to vermiculite-chlorite interstratified mineral and kaolinite. The main variations of the chemical composition are mostly caused by decomposition and the vermiculitization of biotite. The content of the representative interlayer cation, K, depends on that of biotite in the parent granite. Rubidium behaves together with K, so that the Rb fraction is almost constant in the interlayer cations (K, Na, Ca and Rb), despite its low content (below 550ppm) of biotite. Among the possible octahedral cations, substitution of Fe by Mg is remarkable. Contents of minor elements, such as Cu, Zn and Pb, vary locally but no geological evidences for explaining the local enrichments of these elements can be found. Correlation coefficients of Fe and Zn against K suggest that a part of the two elements are contained in the interlayer position.
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  • The identification of the fall-units of the Tokyo pumice bed by chemical composition of ferromagnetic minerals
    Ryuji Aoyagi
    1985 Volume 19 Issue 4 Pages 193-198
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.193
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    Samples of the Tokyo pumice bed were collected from 13 localities. Ferromagnetic minerals contained in the samples were all identified as titanomagnetite by X-ray diffraction method. TiO2 and V2O3 contents of titanomagnetite provide information useful for identifying each fall-unit of the Tokyo pumice bed. The bed at the reference outcrop was divided in 10 fall-units on the basis of visual observation of stratified structure and chemical composition of titanomagnetite. The presence of two additional fall-units was also confirmed by comparative study of samples from different localities. The area covered by a given fall-unit was bounded by using TiO2 content of titanomagnetite separated from each sample.
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  • Gas chromatographic determinations of atmospheric He, Ne and H2
    Iwao Kawabe, Toshihiko Mizutani, Kohei Akaku, Toshihiko Numa, Hideki Y ...
    1985 Volume 19 Issue 4 Pages 199-207
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.199
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    Atmospheric He, Ne and H2 have been determined simultaneously by gas chromatography without any pre-purification procedures for enrichment. Repeated analyses of atmospheric air samples collected in Matsuyama, Japan from 1982 through 1984 have given the following average values with respective standard deviations; 5.20 ± 0.02ppm for He, 18.4 ± 0.1 ppm for Ne and 0.83 ± 0.02ppm for H2. The obtained average values for the atmospheric He and Ne are in good agreement with the commonly accepted values. The concentration of H2, however, is considerably fluctuating even in a short duration less than half an hour, and is affected by meteorological conditions. In particular, the H2 concentration negatively correlates with wind velocity. This trend is clearly seen in rainy days. Exhaust gases from automobile engines are highly enriched in H2, on the order of a percent by volume. The H2-rich exhaust gases are being diluted by less polluted air, and the rate of dilution seems to depend strongly on the wind velocity and precipitation. The average value of H2 concentrations measured in Matsuyama is definitely higher than the background value in surface air of Northern Hemisphere of 0.584 ppm, but comparable to that in the polluted air in Mainz, West Germany reported ten years ago.
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  • Geochemistry and petrology of lavas from San José volcano, Southern Andes (33δ45′S)
    Leopoldo Lopez-Escobar, Hugo Moreno, Michio Tagiri, Kenji Notsu, Naoki ...
    1985 Volume 19 Issue 4 Pages 209-222
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.209
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    San José volcano, one of the northernmost volcanoes of the Southern Andes, is composed of calc-alkaline rocks with SiO2 in the 56–63 wt% range. These rocks have some major-element, trace-element and Sr isotope compositions (0.70513–0.70551) that are intermediate between those of the Central and 37°–46°S Southern Andes andesites. The REE patterns of these rocks exhibit relatively high La/Yb normalized ratios (∼10) with La about 80 times as much as in chondrites and Yb ranging from 6 to 9 times as much as in chondrites. The trace element abundances and SB systematics are consistent with a derivation of the most basic San José andesite from primary magmas, generated by relatively low degrees of partial melting of a garnet-peridotite source, through a crystal fractionation process dominated by olivine, clinopyroxene and plagioclase. The trace element composition of this sample is also consistent with the derivation from a source modified by subduction-related fluids. The relatively high Sr isotopic ratios of the samples suggest that mantle derived magmas are contaminated during their passage through the continental crust.
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  • Is so-called Al-Mg isochron for a meteorite CAI a two component mixing line?
    Noboru Nakamura
    1985 Volume 19 Issue 4 Pages 223-227
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.223
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    An Al-Mg pseudo-isochron is expected for the type B inclusion (CAI) of carbonaceous chondrites on the basis of stoichiometry of anorthite (or hibonite). The linear correlation of excess 26Mg with 27Al/24Mg ratio found for the Allende and Leoville CAI's is well-interpreted as a result of mixing in various proportions (<2%) of two end-members: one with no substantial excess of 26Mg such as spinel, fassaite and melilite, and the other nearly pure anorthite with excess 26Mg (possibly fossil 26Mg) or it's precursor. I would like to call attention to the difficulties in attaining to a “true” Al-Mg internal isochron for meteorite CAI's.
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  • Radioactive strontium fallout from the nuclear-powered satellite Cosmos-1402
    R. K. Guimon, Z. Z. Sheng, L. A. Burchfield, P. K. Kuroda
    1985 Volume 19 Issue 4 Pages 229-235
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.229
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    The presence of 50.5-day 89Sr was detected in most of the rain samples collected at Fayetteville (36°N, 94°W), Arkansas, during the period between 20 February and 3 June, 1983. The pattern of variation of the 89Sr/90Sr ratio in rain indicates that the fresh nuclear debris came most likely from the nuclear reactor on board the Soviet satellite Cosmos-1402, which fell over the South Atlantic Ocean on 7 February, 1983.
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  • High initial Sr-isotopic ratios of gabbro and metadiabase in the Ryoke Belt, Southwest Japan
    Hiroo Kagami, Yoshiaki Tainosho, Shigeru Iizumi, Yoshikazu Hayama
    1985 Volume 19 Issue 4 Pages 237-243
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.237
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    Rb and Sr contents and Sr-isotopic ratios as well as SiO2 and K2O contents were determined for basic rocks (gabbro, cortlandite, anorthosite and metadiabase) from the Ryoke Belt in the Kinki and Setouchi Inland Sea districts, Southwest Japan. The basic rocks are characterized by lower K2O and Rb contents and by higher initial Sr-isotopic ratios than the mantle-derived igneous rocks in the oceanic region. The high initial Sr-isotopic ratios of the basic rocks are explained by the high isotopic ratios of their source materials.
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  • Transformation of aragonite to calcite through heating
    Sayoko Yoshioka, Yasushi Kitano
    1985 Volume 19 Issue 4 Pages 245-249
    Published: August 20, 1985
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.19.245
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    DTA-TG study on several aragonites was carried out to clarify the transformation of aragonite to calcite through heating process. Aragonite formed in biological system started and completed the transformation at temperatures lower than did aragonite formed in inorganic systems. The DTA-TG study showed that weight loss was observed at the appearance of endotherm for coral aragonite and inorganically synthesized aragonites, where the release of water during heating was recognized. Water contained in aragonite seems to have an important role for the transformation through heating.
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  • ERRATA
    1985 Volume 19 Issue 4 Pages e2a
    Published: 1985
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.19.e2a
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  • ERRATA
    1985 Volume 19 Issue 4 Pages e2b
    Published: 1985
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.19.e2b
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