巻号一覧
23 巻 (1989)
- 6 号 p. 269-
- 5 号 p. 215-
- 4 号 p. 149-
- 3 号 p. 91-
- 2 号 p. 45-
- 1 号 p. 1-
23 巻, 4 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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Mitsuru Ebihara, Tetsumaru Itaya, Satoshi Nomura1989 年 23 巻 4 号 p. 149-160
発行日: 1989年
公開日: 2008/04/08
ジャーナル フリーFrom the area along the Aimagawa river in western Gunma, central Japan, 12 samples were collected for the determination of K-Ar ages and chemical compositions. X-ray fluorescence and instrumental neutron activation analysis methods were applied to determine major and trace elements, respectively. Based on the K-Ar ages, the rock samples were divided into two groups having 4.5Ma and 2.0Ma. Although transformation of magnetite to maghemite, possibly due to high temperature oxidation, was observed among the samples, there is no apparent inconsistency between stratigraphic relation and the K-Ar ages, suggesting that such oxidation gave no effect on the K-Ar ages. No large variation is observed in chemical compositions for both major and trace elements. Among the trace elements, lithophile elements such as rare earth elements and Zn show small variations in their abundances. The samples with K-Ar ages of 4.5Ma yield La/Yb ratios larger than 2.5 as chondrite-normalized values, while the remaining samples (ca. 2.0Ma) give values smaller than 2.0, suggesting a difference in the degree of partial melting between the two stages of magmatism. In contrast to the lithophiles, Cr, Ni, and Co show relatively large variations. Chromium shows a positive correlation with 36Ar. Non-radiogenic Ar must have been trapped in some Cr-bearing mineral(s) (chromite and/or clinopyroxene?).抄録全体を表示PDF形式でダウンロード (3044K) -
Jian-Hua Yin, Yoshimichi Kajiwara, Takashi Fujii1989 年 23 巻 4 号 p. 161-180
発行日: 1989年
公開日: 2008/04/08
ジャーナル フリーTransition elements Mn, Fe, Cu, Ni, Co, Zn, V and Cr in the marine surface sediments of the southwestern margin of Japan Sea exhibit clear geographical distribution patterns. Their total contents generally increase with increasing water depth, showing maximum values in the brownish mud which is extensively developed at the depths deeper than about 1000 m. Manganese shows the highest enrichment in the brownish mud, and its distribution pattern in this region is apparently controlled by the redox potential of the sediments. Manganese in the brownish mud is almost entirely extractable with an acid-reducing agent and exists in the form of oxides and/or oxyhydroxides. The extractable Mn is essentially of “suboxic” diagenesis origin, being supplied mainly from the underlying sediments through interstitial water. In contrast, the extractable Fe, Ni, Zn and V in the brownish mud seem to be mainly of hydrogenous origin. In the underlying sediments, these metals are suggested to be incorporated into iron sulfides and hence to make no significant contribution to the upward-migrating components through the interstitial water. Similarly extractable transistion elements in the olive or gray mud from the depths shallower than 1000 m are of hydrogenous orgin.抄録全体を表示PDF形式でダウンロード (4267K) -
Akira Shimoyama, Hiroshi Naraoka, Masatoshi Komiya, Kaoru Harada1989 年 23 巻 4 号 p. 181-193
発行日: 1989年
公開日: 2008/04/08
ジャーナル フリーAnalyses of the Yamato-74662 carbonaceous chondrite (C2) showed the presence of carboxylic acids, and aliphatic and aromatic hydrocarbons with various structural isomers, while those of the Yamato-793321 chondrite (C2) did not. The amounts of these compounds in Yamato-74662 are similar to those reported in the Yamato-791198 chondrite (C2) but less than in the Murchison chondrite (C2). The presence of various structural isomers in carboxylic acids and aromatic hydrocarbons indicated an abiotic origin and therefore, that these compounds are indigenous to the chondrite. n-Alkanes and other homologs of aliphatic hydrocarbons were found. However, these aliphatics may not be indigenous, especially under the finding of pristane and phytane. A potential use of the relative amounts of 1-methylnaphthalene and 2-methylnaphthalene was proposed to deduce the extent of thermal alteration. The result was: Yamato-74662<Yamato-791198≤Murchison. Yamato-793321 probably received the alteration too intensely for these organic compounds to survive and is beyond estimation by this method.抄録全体を表示PDF形式でダウンロード (3337K) -
Eun Soo Kim, Hitoshi Sakai, Jun Hashimoto, Fumitaka Yanagisawa, Suguru ...1989 年 23 巻 4 号 p. 195-208
発行日: 1989年
公開日: 2008/04/08
ジャーナル フリーA mussel, clams, vestimentiferan tube worms and squat lobsters from vent-communities at three volcanically active sites, the Kaikata Caldera of Ogasawara Arc and the Minami-Ensei Knoll and the eastern Iheya Ridge of Okinawa Trough, were analyzed for the concentration and isotopic ratio of sulfur in their soft tissues. The results indicate that the mussel, clams and tube worms are nutritionally supported by endosymbiosis with chemolithotrophic sulfur-oxidizing bacteria which utilize hydrogen sulfide in venting fluid as energy source for organic carbon synthesis, while the squat lobsters live on the chemosynthetic food web. However, the sulfur isotopic ratios of these animals range from -10 to -26‰, much lower than the volcanic sulfur values of these areas (0∼+10‰). This implies that in all the three sites, hydrogen sulfide produced by sulfate-reducing bacteria is an important sulfur source for vent communities. The sulfur flux required for the biological communities is an order of magnitude or two greater than that encountered in normal organic-rich marine sediments. It is suggested that the high heat flow, porous volcanogenic sediments and organic materials accumulated by biological communities play important roles in maintaining high production rate of microbial hydrogen sulfide and its efficient transport to surface in volcanically active seafloor.抄録全体を表示PDF形式でダウンロード (4267K) -
Hiroo Kagami, Hisayoshi Yokose, Hiroji Honma1989 年 23 巻 4 号 p. 209-214
発行日: 1989年
公開日: 2008/04/08
ジャーナル フリーWe have measured 87Sr/86Sr and 143Nd/144Nd ratios for the GSJ rock reference samples JB-1a, JA-1 and JG-1a. The results are as follows; 87Sr/86Sr ratio, JB-1a, 0.704083±0.000016 (2σ, Number of runs is nine), JA-1, 0.703507±0.000016 (N=2), JG-1a, 0.710973±0.000014 (N=3); 143Nd/144Nd ratio, JB-1a, 0.512784±0.000011 (N=1), JA-1, 0.513065±0.000010 (N=1), JG-1a, 0.512377±0.000019 (N=1). According to the compilation by Ando and Shibata (1988), reported data for these reference samples do not concentrate within restricted ranges, and some of them are considerably different from our results. The inter-laboratory difference is partly due to the difference in type of mass spectrometer, but experimental procedures including chemical preparation should also be responsible.抄録全体を表示PDF形式でダウンロード (1337K)
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