巻号一覧
19 巻, 6 号
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Kiriko Tanaka, Morito Koizumi, Riki Seki, Nagao Ikeda1985 年 19 巻 6 号 p. 289-299
発行日: 1985/12/20
公開日: 2008/04/08
ジャーナル フリーMonthly variations of tritium, deuterium and SO42- concentrations in waters from a fumarole, seven hot springs, three rivers, and precipitation in the Nasu volcanic area were measured to investigate their origin and subsurface behavior. Most of waters in the Nasu district including fumarolic condensate are considered to be of meteoric origin on the basis of their δD values. Hot-spring waters are classified into three groups according to their tritium concentration, i.e., the Group A waters with T=30 ∼ 70TR (as of 1974), Group B waters having T=50 ∼ 100TR with seasonal variation, and Group C waters with T=3 ∼ 30TR and high δD values. A model is proposed that the water reservoirs are divided into three stratified aquifers, i.e., layers I, II and III, each of which is characterized by respective tritium concentration. The tritium concentration of the shallowest layer-I water is close to the annual average tritium concentration for precipitation at the time of sampling (1974). The age of the layer-I water is considered to be less than a few years. The layer-II water occurs deeper than the layer-I, and is 5 ∼ 12 years old. The layer-III water occurs beneath Nasu volcano, is very old and contains no tritium. Mixing of waters from the different layers produces Group A, B and C waters. Change in the mixing ratio causes seasonal variation in the isotopic and chemical compositions of some hot-spring waters.抄録全体を表示PDF形式でダウンロード (2749K) -
Fumitake Uyama, Hitoshi Chiba, Minoru Kusakabe, Hitoshi Sakai1985 年 19 巻 6 号 p. 301-315
発行日: 1985/12/20
公開日: 2008/04/08
ジャーナル フリーSulfur isotope exchange reactions in the aqueous system H2S-S2O32--SO42- were studied experimentally in the temperature range from 50 to 170°C and at near-neutral pH using sealed Pyrex glass tubes as reaction vessels. The exchange reaction between thiosulfate and sulfide readily took place above 100°C. The sulfur isotope exchange reaction between inner (sulfonate) and outer (sulfane) sulfurs of thiosulfate was accelerated by coexisting sulfide ions. In other words, the sulfide ions played a catalytic role in the intramolecular sulfur isotope exchange reaction through the formation of polysulfide (e.g., S3S2-, S4S2-) from thiosulfate and sulfide. On the other hand, the sulfur isotope exchange reaction between thiosulfate and sulfate and that between sulfate and sulfide hardly proceeded in about 500 hours even at temperatures as high as 150°C, whereas the sulfane sulfur of thiosulfate exchanged sulfur isotopes with sulfide even at 50°C. The isotope fractionation factor between the sulfonate and sulfane sulfurs of thiosulfate was determined at 120, 130, 150 and 170°C. The results are approximated by the following equation with 34S being favored in sulfonate sulfur. 1000 ln α = −4.94 × 106/T2 + 4.13 × 104/T − 39.03 The half-time of the intramolecular exchange reaction of thiosulfate under presence of sulfide ions was about 15 hours at 120°C and 490 hours at 100°C, respectively. The present results support the view that thiosulfate is an intermediate in the istope exchange between sulfate and sulfide. However further study is required to assess if the intramolecular exchange is the rate-determinant step in the sulfate-sulfide exchange reaction as was suggested by Ohmoto and Lasaga (1982). Variations of the sulfur isotope ratios in natural systems, which possibly involve thiosulfate, were discussed in view of the present results.抄録全体を表示PDF形式でダウンロード (3620K) -
S. C. Lee, A. I. Saleh, A. D. Banavali, L. Jonooby, P. K. Kuroda1985 年 19 巻 6 号 p. 317-322
発行日: 1985/12/20
公開日: 2008/04/08
ジャーナル フリーRadiochemical measurements of 7Be were carried out for a total of 246 individual rain and snow samples collected at Fayetteville (36°N, 94°W), Arkansas, during the period between September 1979 and December 1984. A sharp increase in the 210Po/7Be ratio in rain observed during the winter and spring months of 1980-1981 was attributed to the fallout of excess 210Po from the May 1980 eruption of Mount St. Helens.抄録全体を表示PDF形式でダウンロード (1469K) -
Hiroshi Mizutani, Yuko Kabaya, Eitaro Wada1985 年 19 巻 6 号 p. 323-327
発行日: 1985/12/20
公開日: 2008/04/08
ジャーナル フリーAmmonium fractions from a soil of a penguin rookery in Antarctica and from water of a pond in the rookery exhibit the highest 15N/14N ratios among biogenic nitrogen so far observed. Though soils of seabird rookeries appear, in general, to have high nitrogen isotope ratios, the still higher ratios make the penguin rookery stand out from other seabird rookeries. The observation suggests that ammonia volatilization is a cause of the 15N enrichment in the soil ammonium and that the Antarctic climate is particularly effective on 15N enrichment for ammonium remained in the soil and water.抄録全体を表示PDF形式でダウンロード (1555K)
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