巻号一覧
22 巻 (1988)
- 6 号 p. 237-
- 5 号 p. 183-
- 4 号 p. 143-
- 3 号 p. 89-
- 2 号 p. 47-
- 1 号 p. 1-
22 巻, 5 号
選択された号の論文の5件中1～5を表示しています
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Yasuhiro Kiyosu, Yutaka Yoshida1988 年 22 巻 5 号 p. 183-193
発行日: 1988年
公開日: 2008/04/08
ジャーナル フリーChemical and isotopic compositions were analyzed on geothermal steam from fumaroles and wells in the Takinoue geothermal area. The distribution of deuterium and oxygen-18 in water samples suggests that the fumarole steam discharge is formed from the rising geothermal fluid through a single-step steam separation process at temperatures of approximately 150∼240°C. On the basis of N2/Ar, He/Ar and CO2/N2 ratios, and δ13C values of carbon dioxide in steam, it is concluded that the gas components dissolved in the Takinoue geothermal waters are mixtures of magmatic gases and meteoric waters.抄録全体を表示PDF形式でダウンロード (2534K) -
Ichiro Kaneoka, Makoto Yuasa1988 年 22 巻 5 号 p. 195-204
発行日: 1988年
公開日: 2008/04/08
ジャーナル フリー40Ar-39Ar analyses were performed on five igneous rocks dredged from the continental shelves and slopes around the Yamato Basin in the central part of the Japan Sea during the GH78-2 Cruise of the Geological Survey of Japan. Three igneous rocks dredged from the slopes of the Japanese Islands show 40Ar-39Ar plateau ages of 23-24 Ma. One andesite from the Yamato Bank gives a total 40Ar-39Ar age of about 26 Ma, whereas one basalt from a height of the northern part of the Yamato Basin shows a scattered age spectrum, indicating the existence of excess 40Ar. Except for this sample, the other four rocks seem to be related to volcanic activity which occurred before or during the formation of the Yamato Basin. Based on the present data together with radiometric ages previously reported for the rocks from the Yamato Basin area, the Yamato Basin is estimated to have formed during a period prior to 17 Ma and probably later than about 25 Ma.抄録全体を表示PDF形式でダウンロード (2480K) -
Masaaki Musashi, Masao Nomura, Makoto Okamoto, Tomoko Ossaka, Takao Oi ...1988 年 22 巻 5 号 p. 205-214
発行日: 1988年
公開日: 2008/04/08
ジャーナル フリーBoron isotopic ratios (11B/10B) of 33 hot spring waters from central Japan were determined by mass spectrometry. The water samples can be divided into two groups based on their 11B/10B values: one with higher 11B/10B ratios (about 4.085-4.10), and another with lower 11B/10B ratios (about 4.055-4.065). The 11B/10B values are apparently independent of the pH, temperature, and chemical composition of the waters, but show a systematic regional variation. Hot spring samples from the Nasu, Kusatsu-Shirane, and Hakone areas belong to the higher 11B/10B ratio group while those from the Takayu-Tsuchiyu, Myoko, and Shirahone areas belong to the lower 11B/10B ratio group. This is explainable on the basis that the 11B/10B value of a hot spring water is correlated with that of the boron source from which the aqueous boron is derived, and that the Izu-Bonin arc is strongly influenced by sea water which is enriched in 11B.抄録全体を表示PDF形式でダウンロード (2520K) -
Toshitaka Gamo, Jun-ichiro Ishibashi, Kiminori Shitashima, Masataka Ki ...1988 年 22 巻 5 号 p. 215-230
発行日: 1988年
公開日: 2008/04/08
ジャーナル フリーGeochemical studies of bottom waters and sediments, including deep sea camera surveys and heat flow measurements, were conducted in the western Sagami Bay, central Japan, where dense clam (Calyptogena soyoae) communities had been previously located by submersible observations. The bottom waters above the communities contained an order of magnitude higher CH4 (360∼4200 nl kg-1) than those at nearby stations a few kilometers away from the community site (∼130 nl kg-1), implying significant fluid venting rich in CH4 from the bottom at the very community site. The mean life of the seepage CH4 in seawater was estimated to be several days by using a simple vertical diffusion model. Weak correlations were observed between the concentrations of CH4 and trace metals such as Fe, Mn, Al, and Zn. It was found that the community site is characterized by anomalously high heat flow up to 1680 mW m-2, suggesting volcanic heat sources below the site.抄録全体を表示PDF形式でダウンロード (4373K) -
Makoto Watanabe, Hirotsugu Nishido, Hisamitsu Moriwaki, Sadao Higashim ...1988 年 22 巻 5 号 p. 231-236
発行日: 1988年
公開日: 2008/04/08
ジャーナル フリーUsing K-Ar method, five ages were measured on the minerals: hornblende from the Ushirodani Cu-Zn skarns, Tottori Prefecture (60.7±3.1, 60.8±1.9 Ma); muscovite from the Kuga and Kiwada scheelite skarns, Yamaguchi Prefecture (93.6±2.9 and 94.0±2.9, 101.6±5.0 Ma, respectively). The close time-space relations reveal that the Ushirodani Cu-Zn skarns in the Molybdenum Province have a genetical connection with the granitic magmatism of magnetite-series, while the scheelite skarns such as those of Kuga and Kiwada in the Tungsten Province are genetically related to the ilmenite-series granitoids. Taking consideration of the previously reported ages of other skarn deposits, it is concluded that the ore-bearing skarns, as well as other types of ore deposits in the Molybdenum Province are definitely younger than those in the Tungsten Province, reflecting the difference in ages of granitic magmatism responsible for the mineralization.抄録全体を表示PDF形式でダウンロード (1532K)
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