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Volume 7 (1973)
- Issue 4 Pages 191-
- Issue 3 Pages 123-
- Issue 2 Pages 55-
- Issue 1 Pages 1-
Volume 7, Issue 4
Displaying 1-5 of 5 articles from this issue
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Yasuhiro Kiyosu1973 Volume 7 Issue 4 Pages 191-199
Published: December 20, 1973
Released on J-STAGE: September 26, 2008
JOURNAL FREE ACCESSSulfur isotope fractionation in ZnS-HS- and PbS-HS- systems has been studied experimentally in the temperature range from 50 to 340°C. Sulfur isotopic exchange between sulfide minerals and HS- ions was found to be unexpectedly fast. In the ZnS-HS- system several ten hours are enough to attain isotopic equilibrium in the temperature range from 50 to 200°C. Temperature dependence of equilibrium fractionation was estimated as follows: In αsphalerite-HS-= 111T-2 + 0.00136 In αgalena-HS-=-782 T-2 + 0.00170 From these equations the temperature dependence of sphalerite-galena fractionation is In αsphalerite-galena=891 T-2-0.00057.View full abstractDownload PDF (3879K) -
Yukihiro Matsuhisa, Yoshiaki Tainosho, Osamu Matsubaya1973 Volume 7 Issue 4 Pages 201-213
Published: 1973
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESS18O/16O ratios were analyzed for 14 granitic rocks and their constituent minerals of the Ibaragi granitic complex near Osaka which is composed of the Nosé pluton and the Myoken pluton. The whole-rock δ18O values of the Nosé pluton are in the range from +8.1 to +9.7‰ relative to SMOW. The data for the coexisting minerals suggest that an oxygen isotope equilibrium has been attained among the minerals. The δ18O values of the Myoken pluton are remarkably lower than those of the Nosé pluton. This indicates that the magmas of the two plutons are different in their origins and/or differentiation processes. In the Nosé pluton, the 18O-enrichment of about 1.5‰ is recognized in the differentiation sequence from quartz diorite to adamellite. This isotope variation can be explained as the results of equilibrium fractionation in a crystallizing magma. The δ18O value of the initial magma of the Nosé pluton is estimated to be around +7.5 ‰. Somewhat 18O-enriched materials such as metamorphic basic rocks, rather than the fresh upper mantle materials, are likely to be the source of the 18O-rich dioritic magma. In the Ibaragi granitic complex, no appreciable change in oxygen isotopes is observed in the contact zone as compared to the values of main intrusive body, possibly because the country rocks have isotope ratios similar to those of the granitic rocks. An exception is found in the marginal zone of the Myoken pluton and the dike rocks, where K-feldspar may have exchanged its oxygen with the circulating low-18O meteoric ground water.View full abstractDownload PDF (6471K) -
Nobuhiko Handa, Keisuke Mizuno1973 Volume 7 Issue 4 Pages 215-230
Published: 1973
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSCarbohydrate analysis of the sedimentary samples from Lake Suwa was conducted to ascertain the total amounts of carbohydrates present and their chemical nature, and to discuss the behavior of carbohydrates during the course of sedimentation. Total carbohydrate was determined in the range from 5.92 to 8.32mg/g dry sediment in the samples from the surface to 24cm depth of lake sediments. These values tended to decrease with depth. Lake sediments gave rhamnose, fucose, ribose, arabinose, xylose, mannose, galactose and glucose as the monosaccharide components when the sedimentary samples were treated with sulfuric acid. These monosaccharides were identified as benzoylhydrazones or acetyl derivatives. When alkali extracts of lake sediments were treated by gel filtration using sephadex G-25, low molecular weight carbohydrates and polysaccharide were separated. The polysaccharide, being major component of alkali extractable carbohydrate of lake sediment, was characterized by analyzing monosaccharide composition, degree of polymerization and type of glycosidic linkage between monosaccharide components. Results indicate that this polysaccharide of lake sediment is originated from diatoms living in this lake rather than from land vegetation. Monosaccharide composition of sedimentary samples from various depths was determined. Its vertical profile indicates that stabilities of monosaccharide components of sedimentary carbohydrate to microbiological attack increase in following order; glucose, galactose, fucose > mannose > ribose, rhamnose, arabinose. Vertical profile of low molecular weight carbohydrates indicates that the carbohydrates are intermediates during the decompositive processes of the polysaccharide in the sediment.View full abstractDownload PDF (8217K) -
Akira Miyazaki, Kazuo Sato, Nobufusa Saito1973 Volume 7 Issue 4 Pages 231-244
Published: 1973
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSLead isotope ratios have been measured for early Mesozoic granitic rocks from the Hida metamorphic belt, central Japan. A comparison of the data with those of the Hida metamorphic rocks given in a previous work indicates that the lead in some less abundant granitic rocks may have been contaminated with radiogenic leads from the metamorphic rocks, whereas the lead in the predominant intrusives may not have been subjected to such contamination. The lead isotope ratios of the latter group are further compared with the available data for late Mesozoic granitic rocks and Cenozoic volcanic rocks in Japan. The lead in the granitic rocks from the Hida area is similar to that in the basaltic rocks from the Oki Islands in the Japan Sea and is distinctly less radiogenic than the lead in the granitic rocks occurring in central Japan closer to the Pacific coast, suggesting the presence of a lateral isotopic variation analogous to the general trend found in the Cenozoic volcanic rocks. The applicability of the existing models for lead isotopes in island arcs is discussed.View full abstractDownload PDF (6735K) -
Takeo Sato1973 Volume 7 Issue 4 Pages 245-270
Published: 1973
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSA chloride complex model for Kuroko mineralization at the Uchinotai-nishi deposit of the Kosaka mine is constructed. Possible chemical composition of the ore solution and possible physicochemical properties of the ore-forming environments calculated on the basis of the thermochemical data of HELGESON (1969) can be limited to narrow ranges, if more than 1 ppm Cu is assumed to be dissolved in the ascending Kuroko-forming solution. The model ore-forming environments derived here are consistent with the data of temperature and sulfur fugacity estimated from studies of fluid inclusions, mineral equilibria and sulfur isotopes of the Kuroko deposits. The characteristic mineral zoning of the deposits are explicable by differential precipitation of ore-constituent minerals from the model solutions moving along the gradients of the model ore-forming environments. In order to explain the distribution of sulfate minerals in the deposits, it is necessary to assume mixing of the ascending solution and the coeval seawater. In comparison with the chemistry of the natural metal-rich brines, the model solutions are low in Na/K ratio, while high in Na/Ca and reduced sulfur to metal ratios. It is suggested that these features might be characteristic of volcanogenic ore-forming solutions, which are likely to retain equilibrium conditions at higher temperatures as a result of their rapid ascent from the source reservoir.View full abstractDownload PDF (12722K)
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