地球化学
Online ISSN : 2188-5923
Print ISSN : 0386-4073
ISSN-L : 0386-4073
検索
詳細検索
OR
閲覧
検索
9 巻, 1 号
選択された号の論文の8件中1～8を表示しています
すべての抄録を表示する
    • |<
    • <
    • 1
    • >
    • >|
報文
  • 日本の地球化学の一断面
    松尾 禎士, 山崎 一雄
    1975 年 9 巻 1 号 p. 1-4
    発行日: 1975/06/30
    公開日: 2016/11/08
    DOIhttps://doi.org/10.14934/chikyukagaku.9.1
    ジャーナル フリー
    PDF形式でダウンロード (443K)
  • 太陽系物質中における酸素-16の異常濃縮
    P. K. Kuroda
    1975 年 9 巻 1 号 p. 5-15
    発行日: 1975/06/30
    公開日: 2016/11/08
    DOIhttps://doi.org/10.14934/chikyukagaku.9.5
    ジャーナル フリー
    抄録を表示する抄録を非表示にする
    Correlated variations in 18O/16O and 17O/16O ratios in Al-rich inclusions present in carbonaceous chondrites Allende, Murchison, Murray etc. (Clayton et al, Science 182, 485, 1973) may be explained as due to a combined effect of the processes of mass-fractionation and cosmic-ray irradiation. Consider the relationship
    (17O/16)Q=(17O/16)P(1+μ+C17)
    and
    (18O/16)Q=(18O/16)P(1+2μ+C18)
    where the subscripts P and Q refer to isotopic ratios in a reference standard and in the sample, μ is a term which may be defined as mass-fractionation factor, and C17 and C18 are the contributions from the cosmic-ray-produced 17O and18O. The above equations and the condition that δ17O=δ18O=-50 (permil), where
    δ17O=[{(17O/16O)Q/(17O/16O)P}-1]・1000(permil)
    and
    δ18O = [{(18O/16O)Q/(18O/16O)P}-1]・1000(permil),
    yield the relationships μ=-0.050-C17 and C18=2C17+0.050. The condition δ17O=δ18O=-50 is met if, for example, the cosmic-ray production ratio of 17O and 18O is near unity and μ=-0.020, which corresponds to a value of δ18O=-40 (permil). Under these conditions, one finds C17= -0.0275 and C18=-0.005. The present-day cosmic-ray flux is not sufficient to produce such large variations in the oxygen isotope ratios, but the so-called early irradiation of matter must have taken place during the early history of the solar system. The puzzles of the oxygen, neon, magnesium and xenon isotope anomalies can be explained in terms of a model such as described in this paper.
    抄録全体を表示
    PDF形式でダウンロード (1003K)
例会講演 –南極の地球化学–
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top