GEOCHEMICAL JOURNAL
Online ISSN : 1880-5973
Print ISSN : 0016-7002
ISSN-L : 0016-7002
Search
Advanced search
OR
Browse
Search
Volume 22, Issue 4
Displaying 1-5 of 5 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • Purines and pyrimidines in Neogene sediments of the Shinjo basin
    Akira Shimoyama, Setsu Hagishita, Kaoru Harada
    1988 Volume 22 Issue 4 Pages 143-148
    Published: 1988
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.22.143
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Analysis for purines and pyrimidines was carried out with Neogene sediments in a 1600 m thick stratigraphic sequence in the Shinjo basin. Adenine, guanine, thymine, and cytosine were detected at the 100 ng/g level in the top sediment of the sequence, while guanine and occasionally adenine were chiefly detected at the 10 ng/g level in the remainder of the sediments. The assemblage of these nitrogen bases and their amounts are quite different from those found in recent sediments. These characteristics indicate that the nitrogen bases recovered survived diagenesis and are indigenous to the Neogene sediments.
    View full abstract
    Download PDF (1741K)
  • Isotopic data and rare gas compositions of GSJ rock reference samples, “Igneous rock series”, 1988
    Atsushi Ando, Ken Shibata
    1988 Volume 22 Issue 4 Pages 149-156
    Published: 1988
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.22.149
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Data received by September, 1988 are tabulated for isotopic ratios, isotopic compositions, activity ratios and specific activities of radioactive isotopes, isotopic ages and rare gas compositions of the GSJ rock reference samples, “Igneous rock series.”
    View full abstract
    Download PDF (2004K)
  • Aerosol residence times and iodine gas/particle conversion over the North Pacific as determined from Chernobyl radioactivity
    Mitsuo Uematsu, John T. Merrill, Thomas L. Patterson, Robert A. Duce, ...
    1988 Volume 22 Issue 4 Pages 157-163
    Published: 1988
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.22.157
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Radioactivity from the Chernobyl accident present on aerosols was measured at several island sites and on a ship in the North Pacific. The radioactivity arrived at the various sites located from 11°-64°N between 6-14 May 1986. Isentropic trajectory analyses and measurement of the natural radioactive species 7Be and 222Rn indicate that the continental air containing Chernobyl fission products (e.g., 131I, 137Cs) was transported to the central North Pacific through the middle troposphere. We estimate the residence time and gas-to-particle conversion times by combining the radionuclide data with surface concentration estimates in Japan. The atmospheric residence time over the North Pacific for the aerosols containing the fission products was 3-5 days. The calculated mean gas-to-particle conversion time for radioactive 131I was 2-3 weeks, with a minimum of ∼12 days. The results indicate that the radioactive submicrometer aerosol and the iodine gas from the Chernobyl explosion have residence and conversion times similar to those of naturally occurring aerosols and gases in the atmosphere.
    View full abstract
    Download PDF (1855K)
  • Geochemistry and origin of Pliocene alkali basaltic lavas from Anhui-Jiangsu, eastern China
    Jaroslav Dostal, Claude Dupuy, Mingzhe Zhai, Xiachen Zhi
    1988 Volume 22 Issue 4 Pages 165-176
    Published: 1988
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.22.165
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The Pliocene volcanic rocks of the Anhui-Jiangsu region of eastern China are composed of an alkali basaltic suite consisting of alkali basalts, basanites and nephelinites. The basalts underwent a limited degree of fractional crystallization dominated in the initial stage by olivine and subsequently by clinopyroxene. The magmas were derived from a metasomatized amphibole-bearing garnet peridotite source variously enriched in incompatible trace elements. The metasomatic enrichment of the incompatible trace elements was probably produced by a zone refining process and was superimposed on a depleted upper mantle source compositionally similar to that of mid-ocean ridge basalts.
    View full abstract
    Download PDF (3638K)
  • Atmospheric helium isotope ratio
    Yuji Sano, Hiroshi Wakita, Xu Sheng
    1988 Volume 22 Issue 4 Pages 177-181
    Published: 1988
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.22.177
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The belief that the isotope ratio of air helium is globally constant has meant that air helium is used in most laboratories as a helium isotopic standard. The well accepted air 3He/4He ratio of (1.39±0.01) × 10-6 is an average of the two isotopic determinations by Mamyrin et al. (1970) and Clarke et al. (1976). We measured absolute atmospheric 3He/4He ratio, taking into account the separation of helium from neon and possible occurrence of the helium isotope fractionation during the purification procedure. The 3He/4He ratio of (1.343±0.013)×10-6 observed at Ueno Park, Central Tokyo, Japan is apparently lower than the previous data. The discrepancy may be attributed to either experimental problems or natural phenomenon.
    View full abstract
    Download PDF (1452K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top