巻号一覧
20 巻, 1 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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Yoshimitsu Hirao, Hisao Mabuchi, Etsuko Fukuda, Hideko Tanaka, Tetsuno ...1986 年 20 巻 1 号 p. 1-15
発行日: 1986/02/20
公開日: 2008/04/08
ジャーナル フリーThe annual lead accumulation and the change of the isotope ratios of sediments in the Tokyo Bay are discussed in relation to the development of the Japanese industrial activities. Lead has been spread out from the north western part of the bay, showing a part of concentric circles. The total lead accumulation rate in the bay was calculated to be 17 t/y in 1880, which was regarded as the non-artificial lead input rate, and increased gradually with time reflecting increase in the consumption of lead in Japanese industries. In 1920, the isotope ratios changed extraordinarily, which was estimated to be caused by the introduction of the Broken Hill lead of Australia. The annual lead accumulation has been accelerated since 1950 and the isotope ratios have also been affected by the change in the varieties of the sources. It reached a maximum, 110t/y, in 1970 and was reduced to 71 t/y in 1980. Although the sources of anthropogenic lead are complicated, the gasoline additives would be one of the major sources for the lead pollution until 1970. Although the consumption of gasoline additives in 1980 was reduced to 1/20 of the 1970 value in Japan, the decrease of the gasoline lead seems not yet clearly observed isotopically in the sediments of the bay. The lead in the cored sediments was confirmed not to have moved vertically, but showed a systematic difference horizontally after anthropogenic lead was introduced in the bay. The systematic difference of the isotope ratios in the surface sediments indicates the difference of the pollution sources.抄録全体を表示PDF形式でダウンロード (4187K) -
Kazuhiro Suzuki1986 年 20 巻 1 号 p. 17-27
発行日: 1986/02/20
公開日: 2008/04/08
ジャーナル フリーVariations in the concentrations of trace elements at and near the subgrain-boundaries within olivine phenocrysts in an olivine-nephelinite were inspected with an electron microprobe. The olivine phenocrysts show homogeneous core (Fo85) surrounded by the Fe-richer rim. The core contains 160ppm Ti, 210ppm Al, 170ppm Cr and 140ppm Na, whereas the subgrain-boundary in the core contains 350ppm Ti, 310ppm Al, 490ppm Cr and 590ppm Na. The trace elements with their olivine/bulk-rock concentration ratios smaller than unity (i.e., Ti, Al, Cr, La, Ce, Zn, Ca, Na and K) are enriched at grain-boundaries and cleavages, whereas the concentrations of elements with the ratios larger than unity (i.e., Ni, Mn and Co) are approximately constant. The grain-boundary enrichment of the incompatible elements can be explained in terms of their kinetic segregation on cooling. The present study suggests that the partition coefficients obtained from element concentrations in the phenocrystic minerals and matrix of volcanic rocks do not essentially represent those in magmatic processes in nature. This is important when partitions of trace elements are used in modeling magmatic processes.抄録全体を表示PDF形式でダウンロード (3196K) -
Han-soeb Yang, Yoshiyuki Nozaki, Hitoshi Sakai, Yutaka Nagaya, Kiyoshi ...1986 年 20 巻 1 号 p. 29-40
発行日: 1986/02/20
公開日: 2008/04/08
ジャーナル フリーDuring the KH-80-2 Hakuho-Maru cruise in 1980, four sediment cores were obtained from abyssal basins of the western North Pacific. The cores were analyzed for U, Th, 231Pa, 226Ra, 210Pb, 239, 240Pu and 137Cs. The sediment accumulation rates estimated from 230ThXS and 231PaXS profiles yielded 0.4 to 1 cm/ky. The particle mixing coefficient, DB for top ∼10cm was also estimated from excess 210Pb profiles to range from 0.1 to 0.6cm2/y. Application of a mixing model with two different modes of input (pulse and continuous) showed limited success in reproducing the observed 239, 240Pu and 137Cs. The DB values based on 239, 240Pu and 137Cs data and a continuous input model, however, are roughly equal to those based on 210PbXS except for one core showing subsurface maxima for the fallout nuclides. Generally, the fallout nuclides exist in detectable amounts down to 10-20cm from the surface suggesting relatively rapid transport of these nuclides through burrows. These nuclides may be associated with surface derived, large particles of which food values are high, so that they are segregated and transported by benthic organisms to deeper depths causing separation from 210Pb associated with fine particles. The 210Pb inventory varies considerably from core to core, suggesting patchiness of 210Pb deposition on the sea-floor. 226Ra fluxes are also highly variable depending on location, suggesting inhomogeneous supply from the ocean bottom to the overlying water. The input of 226Ra from Northwest Pacific sediments appears to be small compared to the radioactive decay of 226Ra in the overlying water column. This requires net lateral transport of 226Ra from other regions to the western North Pacific.抄録全体を表示PDF形式でダウンロード (3249K) -
G. Sarazin, G. Michard, Rakotonindrainy, L. Pastor1986 年 20 巻 1 号 p. 41-50
発行日: 1986/02/20
公開日: 2008/04/08
ジャーナル フリーThe geothermal CO2-rich waters of the Antsirabé area result from mixing of hot deep water with superficial groundwaters. The temperature of the deep water was estimated by assuming equilibrium of the hot water with a mineral association characterized by chalcedony as solid silica mineral. The temperature and the CO2 partial pressure at deep levels were estimated to be 150°C and 9-13 atm., respectively.抄録全体を表示PDF形式でダウンロード (2663K) -
Kimitaka Kawamura, Eli Tannenbaum, Bradley J. Huizinga, Isaac R. Kapla ...1986 年 20 巻 1 号 p. 51-59
発行日: 1986/02/20
公開日: 2008/04/08
ジャーナル フリーLow molecular weight organic acids were studied in the course of pyrolysis experiments (200-400°C, 2-1, 000h) of kerogen (Green River Formation and Monterey Formation) with and without the presence of water and minerals (montmorillonite, illite and calcite). C1-C10 aliphatic acids and benzoic acid were identified in the pyrolysis products of kerogen. Their distribution. is characterized by a dominance of acetic acid followed by formic and propionic acids with an even/odd preference in the range of C4-C10. Total concentrations of these acids amounted to 0.3% of initial kerogen, indicating that kerogen has a good potential for producing organic acids. Geochemical implications of these organic acids are; (1) they are possible intermediates from kerogen to natural gas (CO2, H2, CH4, C2H6, etc.) by decarboxylation, and (2) they may be important and potential contributors to the generation of secondary porosity by dissolving minerals.抄録全体を表示PDF形式でダウンロード (2666K)
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