巻号一覧
17 巻, 1 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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Genki Matsumoto, Tetsuya Torii, Takahisa Hanya1983 年 17 巻 1 号 p. 1-8
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリーPhytol and stenols were studied for lake sediments from Syowa and Vestfold Oases in the Antarctic. Phytol and 6 stenols (cholesta-5, 22-dien-3β-ol, cholest-5-en-3β-ol, 24-methylcholesta-5, 22-dien-3β-ol, 24-methylcholest-5-en-3β-ol, 24-ethylcholesta-5, 22-dien-3β-ol and 24-ethylcholest-5-en-3β-ol) were found, with concentrations ranging from 0.099 to 38 and 0.079 to 9.0μg g-1 dry sediment, respectively. The dominant stenols are cholest-5-en-3β-ol, 24-methylcholest-5-en-3β-ol and 24-ethylcholest-5-en-3β-ol. These compounds must be derived mainly from green and blue-green algae, diatoms and mosses. The relative abundances of these stenols should reflect the difference of source organisms in the lakes and the surroundings.抄録全体を表示PDF形式でダウンロード (2314K) -
Noriyuki Tanaka, Shizuo Tsunogai1983 年 17 巻 1 号 p. 9-17
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリー7Be in seawater and sediment trap samples in Funka Bay, Japan was determined together with 210Pb, 210Po and Th isotopes. The sampling was carried out in summer in 1977 and 1979, when the Bay constituted a closed system for mixing with water outside the Bay. The concentration of 7Be of atmospheric origin in seawater did not monotonously decrease with depth, but showed a weak maximum in the intermediate layer. The layer also contained larger amounts of 234Th, 210Po and 210Pb in summer, 1979. The results obtained from sediment trap samples suggest that significant portions of these nuclides and some other heavy metals are transported downward by particulate matter. The residence time of Be in Funka Bay (mean depth 60m) was calculated to be 90–160 days from the activity ratio of 7Be/234Th of the trapped material and the removal rate of 234Th from seawater obtained from the disequilibrium with 238U. These facts also support the TSUNOGAI and MINAGAWA's settling model for the removal of isoluble metals from seawater rather than the irreversible removal from seawater and the rapid transport of these metals in particles.抄録全体を表示PDF形式でダウンロード (2248K) -
Yoshimitsu Hirao, Eiji Matsumoto, Hiroaki Todoroki, Tetsunori Imamura, ...1983 年 17 巻 1 号 p. 19-27
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリーLead concentration and 210Pb activity profiles of 8 core samples from the inner Tokyo Bay were determined. The lead profiles showed a typical lead pollution pattern by human activities. Generally the lead concentration increased gradually from the background level of about 15 ppm before 1900 A.D. to the level in 1940's and then grew up rapidly until 1970. The pollution lead went up as high as about 7 times the natural value in around 1970 in some cores. Since 1970, lead concentration has been decreasing clearly up to date. The average lead accumulation rates in the bay were estimated to be 7.1μg/cm2/y in 1980 and 13μg/cm2/y in 1970. The value of 2.2μg/cm2/y in around 1880 seems close to the natural input rate. More than 75% of the accumulated lead during 1945–1980 was contributed by the pollution lead. Even before that time, 1900–1945, a half of the accumulated lead resulted from the human activities. The values indicate that the Tokyo Bay has been exposed to severe lead pollution for a long time.抄録全体を表示PDF形式でダウンロード (2248K) -
Masahiro Yamamoto, Katsuo Kase, Akira Ueda1983 年 17 巻 1 号 p. 29-39
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリーSulfur isotopes and selenium/sulfur ratios were determined for coexisting pyrite and chalcopyrite from the Kieslager-type deposits of the Hitachi mine, Ibaraki Prefecture, Japan. All pyrite-chalcopyrite pairs analyzed exhibit the normal isotope fractionation, i.e., 34S is more enriched in pyrite than in chalcopyrite. Selenium is more enriched conversely in chalcopyrite than in pyrite. The mean δ34S differences between pyrite and chalcopyrite are 0.84±0.44‰ (11) for the ore bodies of the epidote-amphibolite facies and 0.54±0.24‰ (12) for those of the amphibolite facies. It seems too optimistic, however, to regard the observed differences in the mean value between the two facies as indicating the difference in metamorphic temperature between the two facies, because the magnitude of isotope fractionation is rather variable even within the single ore bodies. Partition of selenium between pyrite and chalcopyrite was found to be virtually the same for both the facies. The mean distribution coefficients of selenium, Dcp-py, are 4.26±0.85 (12) for the epidote-amphibolite facies and 4.44±1.60 (13) for the amphibolite facies. Near-equilibrium trend in sulfur isotope fractionation and rather consistent partition of selenium between pyrite and chalcopyrite strongly suggest that selenium equilibrium is also approached between the two minerals in the Hitachi deposits.抄録全体を表示PDF形式でダウンロード (3310K) -
Kiyoshi Kaneshima, Hatsuo Taira1983 年 17 巻 1 号 p. 41-49
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリーPhysical studies such as differential thermal analysis, thermal gravity analysis, infrared absorption and thermal transformation of mineral phase have been carried out for terrestrial ferro-manganese nodules formed in limestone areas of the Ryukyu Islands. The differential thermal analysis data indicate that they are grouped into four different types regardless of indistinct patterns of X-ray diffractometry. The first group shows endothermic peaks at near 120, 320 and 560°C. The second goup is close to the first group except showing a quite enhanced endothermic peak at 320°C. The third type of nodules shows one more additional endothermic peak at near 800°C. The final fourth group shows only two endothermic peaks at near 120 and 560°C. The X-ray diffraction patterns for heated samples at various temperatures indicate that magnetite is formed at temperatures over 700°C. Braunite also seems to be formed at the same temperature range but it disappears at 1, 000°C. The mineral composition of the manganese nodules has been also discussed by the study of infrared absorption patterns with particular reference to quartz, goethite, amorphous state of ferrihydrite and artifitially formed silica gel.抄録全体を表示PDF形式でダウンロード (2314K) -
A. M. Kudo1983 年 17 巻 1 号 p. 51-62
発行日: 1983/02/20
公開日: 2008/04/08
ジャーナル フリーKUNO (1950, 1959) first identified the existence of two rock series in the Japanese volcanic arc and proposed the origin of one from the other by assimilation of granitic material. In the Nasu zone in northeastern Japan, both the tholeiitic suite with pigeonite in the groundmass and the calc-alkalic suite with hypersthene as the Ca-poor pyroxene in the groundmass have been shown to have erupted from one volcano and to have differences in major element chemistries (KAWANO and AOKI, 1960; KAWANO et al., 1961). MASUDA and AOKI (1979), using mainly trace elements, showed that the calc-alkalic suite has higher Mg, K, Co, Cr, Ni, Th, and U than the tholeiitic suite, and also that each suite had a separate fractional crystallization. A model is presented here which is intended to explain both the mineralogical and chemical differences. KUNO's idea of assimilation is considered from a different point of view; that is, calc-alkalic basaltic andesite is formed by the partial assimilation of mafic rather than granitic material by a silicic tholeiitic andesite. Changes in the chemistry, mainly in the Mg/Fe ratio in the contaminated magma, prevents the crystallization of pigeonite; a drop in temperature as KUNO suggested is not as important although lower temperatures will help. It is demonstrated how such elements as K, Th, and U, which tend to be concentrated in granitic material, can be increased in the calc-alkalic rocks by addition of mafic xenoliths. This process is offered as an alternative to magma mixing, since it is believed that the mineralogical features used to support magma mixing could be explained equally well by assimilation.抄録全体を表示PDF形式でダウンロード (3893K)
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