巻号一覧
21 巻 (1987)
- 2 号 p. 39-
- 1 号 p. 1-
21 巻, 2 号
選択された号の論文の7件中1～7を表示しています
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日下部 実, 大隅 多加志1987 年 21 巻 2 号 p. 39-47
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーOutbursts of a large volume of carbon dioxide took place on 21 August 1986 at Lake Nyos, Cameroon, leading more than 1700 lives to death by asphyxiation. Geochemical and limnological survey made some 50 days after the disaster revealed that the lake water was still stratified with respect to temperature, chemistry and density except a very surface layer. The dissolved species were overwhelmingly dominated by CO2 (aq) and HCO3- with a substantial concentration of Fe2+ in deep waters. Stable isotopic compositions of carbon (δ13C=-3‰) and helium (5.7 times the atmospheric 3He/4He ratio) strongly indicate a mantle origin of the gases. Very low concentrations of Cl- and SO42- argue against the volcanic gas injection hypothesis as a cause of the disaster. The gas bursts were caused by outgassing of CO2-laden deep water which was displaced upward and effervesced near the surface, possibly triggered by an increased input rate of warmer, CO2-charged groundwater from the bottom during the rainy season.抄録全体を表示PDF形式でダウンロード (932K)
報文
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水谷 義彦, 佐竹 洋, 高島 秀樹1987 年 21 巻 2 号 p. 49-54
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーGroundwater system of the Shogawa fan, Toyama, consists of six divisions of aquifers. Each aquifer has characteristic water quality. Present study used tritium measurement to estimate the age of the groundwaters. The piston-flow model indicated that the waters of division 1 from the Oyabe river and division 2 from Takashozu range are less than 3 years old. Age of the groundwater in a southern part of division 3 (from the Sho river) is estimated to be less than 1 year. At a northern part of division 3, old water from a deep confined aquifer appeared to flow into young water of a shallow confined aquifer. Waters of more than 30 years of age were found in divisions 4 and 5. In these divisions, groundwaters of markedly different tritium concentration coexisted. This coexistence suggests little mixing of groundwaters in these areas. Tritium measurement, thus, gives valuable information concerning the origin and subsurface behavior of groundwaters.抄録全体を表示PDF形式でダウンロード (566K) -
三好 登和子, 今橋 正征, 吉野 諭吉, 甲木 和子原稿種別: 本文
1987 年 21 巻 2 号 p. 55-64
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーCalcium sulfate hemihydrate was synthesized in NaCl-solutions to determine the apparent partition coefficient of strontium (Dsr) between the hemihydrate and its solution. Hemihydrate containing about 5% sodium ions (Na-hemihydrate ) precipitated from NaCl-saturated solution at temperatures between 64℃ and 95℃. If the temperature was below 64℃, gypsum (Na-free) formed in the solution, while anhydrite (Na-free) was found above 95℃. Crystal water was more stable in Na-hemihydrate against heating than in Na-free hemihydrates. This may be due to hydrogen bonds in Na-hemihydrate. Na-hemihydrate had the largest value of Dsr (2.1 to 2.5) among calcium sulfate polymorphs. Substitution of one calcium ion by two sodium ions may make more lattice sites available for strontium ions. Na-free hemihydrates were unstable in Na-free solutions when the temperature was below 100℃. Bassanite (hemihydrate mineral), however, does exist in evaporative environments such as continental sabkha zone pans. A high salt concentration may stabilize the mineral in these environments.抄録全体を表示PDF形式でダウンロード (989K) -
坂田 将, 牧 真一, 矢崎 清貫, 永田 松三1987 年 21 巻 2 号 p. 65-74
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーTo investigate a possibility of oil and gas accumulation, we analyzed surface sedimentary rocks and subsurface gases from the Neogene to the Mesozoic in the southern Kii Peninsula, Japan. Rock samples yielded total organic carbon (TOC of 0.20〜1.94% (av. 0.53%) and extractable hydrocarbon (HyR) of 9〜53 ppm (av.22 ppm). Plot of HyR versus TOC suggested most samples to be a lean oil source or a possible source of methane. Atomic H/C ratio of kerogen from the rock samples was 0.40〜0.66 (av. 0.49). Van Krevelen Diagram showed high maturities of these samples, but could not determine kerogen types. CH4 content of gas samples was 0.000〜93.7%, mostly being higher than 1%. Plot of C1/(C2+C3) versus δ13C(CH4)PDB indicated their hydrocarbons to be thermocatalytic products of organic matter. CH4 was likely to have been concentrated against other hydrocarbons during migration.抄録全体を表示PDF形式でダウンロード (1054K) -
角皆 静男1987 年 21 巻 2 号 p. 75-82
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーThere are various models for oceanic removal of reactive elements of short residence time. Among them, a model proposed by Tsunogai and Minagawa (1978) appears to fit well recent findings from sediment trap experiments. The findings include that biogenic particles containing SiO2 and CaCO3 as major components reach a deep-sea bottom without serious alteration. Radionuclides of reactive elements such as Th and Pb in seawater and in particles indicate an active transformation of particles between large settling aggregates and small suspended particles including those passing through filter papers. Furthermore, increases with depth in fluxes of Al and of other metals and in the ratio of Mn/Al for settling particles in the world ocean suggest that horizontal diffusion and advection are strong. Also, small particles appear to regenerate enormously from large particles at sea-bottom interface, especially in shallow seas. While these findings agree with the model, they also make desirable for it to take into account horizontal motions of water and the particles and to extend to all chemical constituents in the ocean. Therefore, I here present a new model, "train-passengers model". The train is a rapidly sinking large aggregate particle, while the passengers are small particles of clay, oxides, hydroxides, insoluble organic molecules, etc. Further studies based on the new model can be planned to make quantitatively clear the behavior of chemical constituents in the ocean.抄録全体を表示PDF形式でダウンロード (804K)
ノート
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吉田 尚弘, 水谷 義彦1987 年 21 巻 2 号 p. 83-90
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーA simple preparative procedure for oxygen-18 determination of water is presented. Water is equilibrated with carbon dioxide in a polypropylene syringe under an atmospheric pressure. This eliminates many pre-equilibration steps in vacuo and shortens the time for isotope equilibration. Carbon dioxide is extracted only from gaseous phase, and separated from water vapor by a flow-through process. This effectively eliminates some post-equilibration steps. Principle of the method is the same as that of the conventional carbon dioxide equilibration technique. And the accuracy of ±0.04 per mil remains. The method can be used for routine oxygen isotope determination of water samples with no new equipments and little training.抄録全体を表示PDF形式でダウンロード (817K) -
大関 正春, 渋谷 信雄, 田海 直樹, 松本 英二1987 年 21 巻 2 号 p. 91-94
発行日: 1987/12/10
公開日: 2016/11/30
ジャーナル フリーWe report the records of mercury pollution in the Seki River which is located at the southwest of Niigata Prefecture. The sediment cores were taken from off the river mouth, and their sedimentation rates and mercury concentrations were measured. The mercury concentration change in the sediment cores were roughly related with the records of mercury consumption in three factories which are located in the Seki basin.抄録全体を表示PDF形式でダウンロード (455K)
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