GEOCHEMICAL JOURNAL
Online ISSN : 1880-5973
Print ISSN : 0016-7002
ISSN-L : 0016-7002
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Volume 6, Issue 1
Displaying 1-4 of 4 articles from this issue
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  • Strontium and calcium coprecipitation with lead-bearing barite from hot spring water
    Bokuichiro Takano, Kunihiko Watanuki
    1972 Volume 6 Issue 1 Pages 1-9
    Published: 1972
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.6.1
    JOURNAL FREE ACCESS
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    The amounts of strontium and calcium in the lead-bearing barite from hydrothermal solution were found to increase with the lead content of the barite. This fact suggests that the difference between DMPbSO4 = [M/Pb]PbSO4/[M/Pb]aq and DMBaSO4 = [M/Ba]Baso4/[M/Ba]aq primarily contributes to the increment of both trace elements in the barite, where DMPbSO4 and DMBaSO4 represent the distribution coefficients of M which refers to strontium or calcium; [M/Pb] and [M/Ba] indicate the M-lead and M-barium weight ratios, respectively, in sulfate and aqueous solution.
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  • Discrepant results of C-14 and fission track datings for some volcanic products in southern Kyushu
    Kazuo Sato, Shigeo Aramaki, Jun Sato
    1972 Volume 6 Issue 1 Pages 11-16
    Published: 1972
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.6.11
    JOURNAL FREE ACCESS
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    Seven charcoals from the Ito pyroclastic flow deposits in southern Kyushu show discordant C-14 ages, ranging from 2, 460 to 38, 900y. To obtain the upper limit of age for the Ito pyroclastic flow, three obsidians from the Arasaki pumice fall deposits underlying the Ito were dated by fission track method. The ages of the obsidians range from 31, 000 to 41, 000y. Possible sources of error in the C-14 dating are discussed.
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  • Pleistocene dolomite and associated carbonates in south Okinawa, the Ryukyu Islands
    Kenji Konishi, Kiyoshi Kaneshima, Koichi Nakagawa, Hitoshi Sakai
    1972 Volume 6 Issue 1 Pages 17-36
    Published: 1972
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.6.17
    JOURNAL FREE ACCESS
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    Pleistocene calciferous dolomite occurs in association with, besides pyrite and carbonaceous matter, either (1) magnesian calcite, calcite and aragonite, or (2) calcite with or without aragonite, in fossiliferous wackestone of the Naha Limestone in south Okinawa. This difference in mineralogical assemblages depends on the degree of leaching through subaerial weathering, which was witnessed by the systematic difference in Cl-, SO42- and organic carbon and pyrite contents of the carbonate rocks and by a negative shift of δ13C in the associated calcite. The dolomite has an isotopic composition δ13C =-15∼-36‰ and δ18O = +3∼+4‰ relative to the PDB standard. The conspicuous depletion of 13C, accompanied by enrichment of 18O in the dolomite is ascribed to dolomite formation from replacement of aragonite and magnesian calcite in contact with a hypersaline brine under a subtropical-restricted circulation where degradation of organic matter formed carbon dioxide enriched in 12C. A shallow subsurface environment, possibly together with the development of a back-reef lagoon, may be a plausible site of the dolomitization. This paper is the first to report the 13C-depleted dolomite from definitely shallow-water reefy sediments.
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  • Distribution of uranium and thorium among components of some chondrites
    Hideki Matsuda, Masako Shima, Masatake Honda
    1972 Volume 6 Issue 1 Pages 37-42
    Published: 1972
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.6.37
    JOURNAL FREE ACCESS
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    The distribution of uranium and thorium was studied in the fractionated components of several chondritic meteorites. A wet fractionation method was applied to separate the component mineral groups of powdered samples of two olivine-hypersthene chondrites, one olivine-bronzite chondrite, and three enstatite chondrites. Uranium was determined in four samples and thorium was determined in all six samples. Both element determinations were by neutron activation. Uranium was found to be enriched in the HCI soluble fraction of the hypersthene chondrite Bruderheim, and of the enstatite chondrites, Abee and St. Marks, whereas it was enriched in the HCI insoluble fraction of the bronzite chondrite, Richardton. On the other hand, thorium was found to be relatively concentrated in the HCl soluble fractions of enstatite chondrites and in the HCl insoluble fractions of all the ordinary chondrites we examined. In ordinary chondrites thorium behaves as a lithophile element, whereas in enstatite chondrites it seems to be partly chalcophile.
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