巻号一覧
8 巻 (1974)
- 4 号 p. 157-
- 3 号 p. 109-
- 2 号 p. 47-
- 1 号 p. 1-
8 巻, 3 号
選択された号の論文の6件中1～6を表示しています
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Takaaki Fukuoka1974 年 8 巻 3 号 p. 109-116
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーConcentrations of uranium, and concentrations and isotopic ratios of thorium in zircon and glass were determined for pyroclastic dacite pumices in southern Kyushu, Japan, and lo-ages were calculated. Uranium and thorium distributions in other minerals were also determined. Uranium and thorium contents of minerals were highest for zircon and decreased in the order, zircon-apatite-glass-mafic minerals-plagioclase. Zircons showed the highest U/Th activity ratios compared with other minerals. Io-ages obtained by glass-zircon pair for pyroclastic flows in southern Kyushu, except for Ata pyroclastic flow were consistent with 14C and fission track ages and the stratigraphic sequence. Comparison of uranium and thorium concentrations in mineral constituents of acidic volcanic rocks showed that the glass-zircon pair is the most preferable for ionium dating.抄録全体を表示PDF形式でダウンロード (3851K) -
Takaaki Fukuoka, Kunihiko Kigoshi1974 年 8 巻 3 号 p. 117-122
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーIo-ages obtained for glass-zircon pairs which were not consistent with expected ages were discussed on the basis of uranium and thorium distribution between zircon and glass. Uranium and thorium distribution between zircon and host rocks from dacites and granites were also discussed. Discordant Io-ages obtained for glass-zircon pairs with normal (Th/U)zircon/(Th/U)glass ratio are explained by early stage crysallization of the zircon in the magma. Discordant Io-ages with abnormal (Th/U)zircon/(Th/U)glass ratios suggest that the zircon was captured in the magma as xenoryst. The discrepancy between (Th/U)zircon/(Th/U)glass ratios (about 0.19) for dacites and (Th/U)zircon/(Th/U)whole rock ratios (about 0.12) for granites could be explained by crystallization of granitic zircon from liquid having chemical composition different from that of the whole rock of granite.抄録全体を表示PDF形式でダウンロード (2422K) -
Toshio Yamamoto, Setsu Kadowaki, James H. Carpenter1974 年 8 巻 3 号 p. 123-133
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーA general practical method for the determination of chromium in various marine substances has been developed using photometric measurements of diphenylcarbazide complex. Organic matter in the sample solution was decomposed by potassium permanganate, and chromate was reduced to chromium (III) by hydroxylamine in a dilute sulfuric acid solution. Chromium (III) was separated completely from iron, manganese and chloride etc. by several coprecipitations with aluminum hydroxide in the presence of hydroxylamine. The separated chromium (III) was oxidized to chromate with silver peroxide and colored complex formed. A half μg of chromium was easily determined in 10ml of the final solution. The method was applied to solid substances settled from sea water, to fine solid substances removed by high speed centrifuge from sea water, to a number of surface and deep sea water samples collected from the Northern North Pacific Ocean, to shallow sea deposits in Chesapeake and Tokyo Bays, to deep sea deposits in the Middle and South Pacific Ocean and to some Japanese seaweeds.抄録全体を表示PDF形式でダウンロード (5337K) -
Yoshimasu Kuroda, Tetsuro Suzuoki, Sadao Matsuo1974 年 8 巻 3 号 p. 135-139
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーThe δD values of hornblendes from some granites and ultramafic-mafic rocks suggest that the water in granitic magma and the water equilibrated with hornblendes in ultramafic-mafic rocks associated with peridotites seem to be the same with respect to δD values which range from -29 to -37‰. Water contents of hornblendes in ultramafic-mafic rocks are clearly higher than those in granitic rocks. The δD values and water contents of hornblendes from nodules in some alkali basalts and possibly metamorphosed ultramafic-mafic rocks are quite different from those of the rocks mentioned above.抄録全体を表示PDF形式でダウンロード (2398K) -
Shizuo Tsunogai, Kazuyoshi Fukuda1974 年 8 巻 3 号 p. 141-152
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーThe concentrations of 210Pb, 210Bi and 210Po in rain and snow were determined. Extremely high concentrations of 210Pb, e.g. 190dpm/l, were observed for snow produced from convective clouds by the north-west monsoon on 3 Feb. 1972, at Assabu, Hokkaido. The high concentration is due to the active convection in the continental air mass which contains much radon and has rather low absolute humidity. The 210Bi/210Pb ratio was higher in rain in summer than in snow in winter. By using the two models, CRM (continuous removal model) and SRM (sudden removal model), the residence times of aerosols in the atmosphere are calculated from the activity ratios, 210Bi/210Pb and 210Po/210Pb. The residence time from the 210Bi/210Pb ratio is apt to be shorter for the snow by the winter monsoon. This is due to the addition of aged aerosols which may come from the lower stratosphere to the troposphere. By resolving the simultaneous equations, the percentage of aged aerosols and the true residence time of tropospheric aerosols are estimated to be 1 to 5% and 2 to 7 days for the snow produced by the winter monsoon. The residence time, however, varies widely owing to the origin and history of the air mass.抄録全体を表示PDF形式でダウンロード (5891K) -
Jun-ichi Matsuda1974 年 8 巻 3 号 p. 153-155
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーA linear isochron can be obtained even for an open system. The gradient of this “virtual isochron”, however, is different from that of “true isochron”.抄録全体を表示PDF形式でダウンロード (1112K)
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