巻号一覧
32 巻 (1998)
- 6 号 p. 351-
- 5 号 p. 281-
- 4 号 p. 213-
- 3 号 p. 143-
- 2 号 p. 71-
- 1 号 p. 1-
32 巻, 5 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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Hoi-Soo Jung, Man-Sik Choi, Dongseon Kim, Hyun-Ju Cha, Kyeong-Yong Lee1998 年 32 巻 5 号 p. 281-299
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリーMajor factors controlling the variation of rare earth element (REE) contents in deep-sea sediments were identified using box-core sediments from the Korea Deep Ocean Study (KODOS)-90 site in the western part between the Clarion-Clipperton fracture zones, northeast equatorial Pacific. Four of ten core columns can be divided into two layers by a sharp color boundary; an upper pale brown layer (Unit A) and a lower dark brown layer (Unit B). Trivalent REEs (3 + REEs) as well as micronodules, smectite, smectite aggregate, and fish remains (spicules and spines) are highly enriched in Unit B compared to Unit A. 3 + REEs in micronodule, smectite, and smectite aggregate are not significantly concentrated compared to those in bulk Unit B sediments. 3 + REE contents in coarse-grained fish remains (>25 μm), which is likely biogenic apatite, are about seven and two times higher, respectively, than the contents in Units A and B. Contents of fish remains in bulk Unit B sediments, however, are too low to explain the enrichment of 3 + REEs in Unit B. Based on the results of phosphorus speciation and linear relationships in two pair diagrams (La contents vs. total inorganic phosphorus and 1/(Ce/Ce∗) vs. total inorganic phosphorous), it can be inferred that 3 + REEs are dominantly enriched in apatite in fine sediments (<25 μm) with strong negative Ce anomaly and convex-type distribution pattern of REEs normalized with NASC. It is suggested that apatite grains, supplied abundantly from surface water during the time of Unit B formation with high paleo-productivity, had incorporated and concentrated 3 + REEs.抄録全体を表示PDF形式でダウンロード (4741K) -
Tasuku Akagi, Akimasa Masuda1998 年 32 巻 5 号 p. 301-314
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリーThermodynamic condition necessary for the appearance of negative Ce anomaly has been calculated with the simplest assumption that cerianite (CeO2) is a unique species of Ce(IV) in water system and that hardly soluble nature of CeO2 is the direct cause of the Ce anomaly. Only negative Ce anomalies possess straightforward information on the chemical conditions responsible for the anomalies. The extent of Ce anomaly has been calculated on the basis that the maximum dissolved concentration of Ce is limited by the maximum of activity of Ce3+ (aCe3+) allowed by the formation of cerianite, which is determined mainly by pH and EH. In the calculation the activities of Ce in any solid phases are assumed to be unity. The Ce anomaly line exhibiting a certain magnitude of negative anomaly was invented and drawn in the EH-pH diagram. We then applied the Ce anomaly line to some natural samples (seawater, ground water, iron formation, etc.) showing negative Ce anomalies and found that the Ce anomalies fairly well reflect the EH-pH condition of the aqueous phase. In applying the Cc anomaly line to natural systems, the key parameter is the activity of Ce∗3+, not the concentration of Ce∗ (hypothetical Ce without Ce(IV) states). Too much credence, however, should not be given to the simple calculation, owing to the complication of the natural system and the lack of appropriate thermodynamic data.抄録全体を表示PDF形式でダウンロード (3521K) -
Masayuki Minakawa, Shinichiro Noriki, Shizuo Tsunogai1998 年 32 巻 5 号 p. 315-329
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリーTotal dissolvable manganese in sea water was measured vertically from the surface to the bottom at 10 stations in the Bering Sea and the northern North Pacific Ocean. High concentrations of manganese were found in the surface and the bottom layers in the Bering Sea, suggesting that the surface water in the continental shelf region and the surface sediment were the principal sources of manganese. In the northern North Pacific, concentrations of manganese increased toward the Bering Sea. This result suggests that the water outflowing from the Bering Sea basin is a significant source of manganese to the northern North Pacific intermediate and deep waters. From manganese budget in the Bering Sea, the residence time of manganese in the Bering Sea and the outflow of manganese to the northern North Pacific from the Bering Sea were estimated to be approximately 8 years and 5 × 109 gMn/yr, respectively. The overall balance showed no net accumulation of TDMn within the Bering Sea, indicating that almost all TDMn supplied was transported to the North Pacific and Arctic oceans.抄録全体を表示PDF形式でダウンロード (3433K) -
Masahiro Sakata, Kiyoshi Suzuki1998 年 32 巻 5 号 p. 331-338
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリーA method using δ13C records of annual growth rings has been proposed for assessing environmental stresses in mature forest trees. First, we calculate the change with time in the difference (Ca-Ci) between the CO2 concentration in the atmosphere and the leaf intercellular spaces from the δ13C records in tree cellulose based on a carbon isotope fractionation model for C3 plants. The Ca-Ci value is dependent primarily on the mesophyll capacity for photosynthesis and the supply of CO2 through the stomata. Next, stomatal limitation of photosynthesis is evaluated from the ratio of ring area to Ca-Ci which is possibly indicative of leaf conductance. These parameters for the trees from a declining grove of Japanese cedar (Cryptomeria japonica) in the Kanto Plain, Japan were suggested to respond sensitively to the changes in air pollution (mainly SO2) and/or dry atmospheric conditions. This method offers a potentially useful research tool for evaluating possible causes for forest decline.抄録全体を表示PDF形式でダウンロード (1908K) -
Etsuo Uchida, Ryo Inoue, Koichi Ogiso1998 年 32 巻 5 号 p. 339-344
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリーAqueous speciation of cadmium in 2 M chloride solutions was determined at 500 and 600°C, 1 kbar and 600°C, 0.5 kbar in the system CaTiO3-CdTiO3-CaCl2-CdCl2-NaCl-H2O using the same experimental method as Uchida et al. (1998). Thermodynamic analysis of the experimental results gives 1.3, 2.3 and 2.9 for the logarithm of the stepwise formation constant of tri-chloro cadmium complex at 500 and 600°C, 1 kbar and 600°C, 0.5 kbar, respectively. The formation constant increases with increasing temperature and decreasing pressure.抄録全体を表示PDF形式でダウンロード (1326K) -
Takashi Miyazaki, Kenji Shuto1998 年 32 巻 5 号 p. 345-350
発行日: 1998/10/20
公開日: 2008/04/08
ジャーナル フリー87Sr/86Sr and 143Nd/144Nd ratios for twelve GSJ rock reference samples (GSJ-RRS), together with the chemical standards NBS987, La Jolla and JNdi-1, have been measured on a MAT262 mass spectrometer in the Department of Geology, Niigata University. Measurements of five to nine aliquots for each GSJ-RRS gave small standard deviations of both Sr and Nd isotopic ratios.抄録全体を表示PDF形式でダウンロード (1389K)
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