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, 4 号
選択された号の論文の4件中1～4を表示しています
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Naoko Ueno, Ichiro Kaneoka, Minoru Ozima1974 年 8 巻 4 号 p. 157-164
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーOne granodiorite, two basalts and five andesites dredged from seamounts and banks in the Japan Sea were studied by means of K-Ar and Rb-Sr dating methods. The granodiorite gives a concordant age of 227m.y, while the ages of the basalts and andesites range from 4 to 22m.y. The Sr isotopic ratios (87Sr/86Sr)0 of these samples are higher than the mean for island basalts.抄録全体を表示PDF形式でダウンロード (3519K) -
Sadao Matsuo, Tetsuro Suzuoki, Minoru Kusakabe, Hiroaki Wada, Masaru S ...1974 年 8 巻 4 号 p. 165-173
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーD/H and 18O/16O ratios of fumarolic condensate, hot spring water and surface water collected from a volcanic island, Satsuma-Iwojima were determined together with some of chemical components. δD and δ18O of fumarolic condensates range from -27 to -17‰ (SMOW) and from +7.3 to +9.5‰ (SMOW), respectively. The high value of δ18O was concluded to be the result of thorough oxygen isotope exchange with ambient andesitic rocks. δD values are also higher than that of the local surface water, but we could not find a positive evidence that supports the assumption of mixing of the local surface water and sea water. On the basis of the relationship between the concentration of chemical components and isotope ratios of fumarolic condensates, it was concluded that water vapor and chemical components behave independently in an individual fumarole.抄録全体を表示PDF形式でダウンロード (4251K) -
Atsushi Ando, Hajime Kurasawa, Teiko Ohmori, Eizo Takeda1974 年 8 巻 4 号 p. 175-192
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーAnalytical data received by October, 1974 for rock analyses, 53 minor elements and strontium isotopic ratios of the GSJ JG-1 granodiorite and JB-1 basalt are tabulated: Averages for both major and minor elements are given.抄録全体を表示PDF形式でダウンロード (7168K) -
Ken Shibata1974 年 8 巻 4 号 p. 193-207
発行日: 1974年
公開日: 2008/04/08
ジャーナル フリーWhole-rock samples of the Hikami granite from the southern Kitakami mountains in Northeast Japan give a Rb-Sr age of 339 ± 12m.y with an initial 87Sr/86Sr ratio of 0.7079 ± 0.0003, indicating that the granite intruded in the late Devonian to early Carboniferous time. A slightly high initial 87Sr/86Sr ratio for the Hikami granite suggests that the granite assimilated some amount of older crust. The Tsubonosawa gneiss, which is contained in the Hikami granite as xenolithic masses, gives an isochron age of 334m.y with an initial 87Sr/86Sr ratio of 0.7129. The results show that the Sr isotopic homogenization occurred among the whole masses of the gneiss at the time of granite intrusion. A higher initial 87Sr/86Sr ratio suggests that the gneiss originated in the Precambrian time. Granite boulders from the Devonian Ono formation do not define any isochron, whereas the sandstone from the Silurian Kawauchi formation gives an apparent age of 264m.y. The whole-rock systems of boulders and sandstone may have remained open with respect to Rb and Sr, probably because of their involvement in sedimentary process. The Rb-Sr isotopic data for the Cretaceous Tono and Kesengawa granites confirm the evidence that almost all igneous rocks in Northeast Japan, irrespective of age, have low initial 87Sr/86Sr ratios, reflecting a distinctive nature of crust in Northeast Japan.抄録全体を表示PDF形式でダウンロード (7160K)
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