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Volume 11 (1977)
- Issue 4 Pages 183-
- Issue 3 Pages 111-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 11, Issue 4
Displaying 1-11 of 11 articles from this issue
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Hideki Wada1977 Volume 11 Issue 4 Pages 183-197
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSCarbon and oxygen isotopic compositions of graphite and coexisting carbonate were determined for the regional metamorphic areas of Kurobegawa, Toyama Pref. and Kamioka, Gifu Pref. as well as the contact metamorphic aureoles of Kasuga, Gifu Pref., Ikeno, Aichi Pref., Ikenojizo, Kyoto Pref., and Ugakei, Mie Pref. in central Japan. In graphite bearing crystalline limestones, carbonate-graphite pairs are considered to have been in carbon isotopic equilibrium during various metamorphisms. In the contact metamorphic aureoles of the Kasuga area, the carbon isotopic geothermometry gives a temperature similar to that estimated from the mineral assemblages. There is a local variation of carbon isotopic temperatures from 470 to 740°C within one hundred meters from the igneous contact in the Kasuga area. This would be attributed to the heterogeneity of the metamorphic temperatures near the igneous contact. On the other hand, in the regional metamorphic terrane of the Kurobegawa area, the carbon isotopic fractionation between graphite and coexisting carbonate is almost constant for gray limestone. This would show that the metamorphic temperature is constant during metamorphism within an area of at least a few square kilometers. In the polymetamorphic terrane of a part of the Kurobegawa area, the carbon isotopic temperature represents the maximum temperature of the late stage of a progressive metamorphism. In the Kamioka area, the isotopic geothermometry gives a temperature higher than 810°C, which is far above the metamorphic temperature expected from mineral assemblages. This high grade metamorphism would have occurred at an early stage of the Hida polymetamorphism.View full abstractDownload PDF (4482K) -
Motomu Nikaido1977 Volume 11 Issue 4 Pages 199-206
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSThe processes of methane production in bottom muds containing sea water sulfate were investigated in relation to both sulfate reduction and organic acid fermentation. The methane production in bottom muds was dependent on the degree of sulfate reduction, and did not occur until about 80% of sea water sulfate was removed by sulfate reduction. The activity of methane production in bottom muds was not inhibited even under the sulfide-S concentration of 160mg per 100g wet mud, and was directly dependent on the amount of organic acids. When the bottom mud added with phyto-plankton was incubated at 20°C for 20 days, sulfate decreased with consumption of lactic acid, and acetic and propionic acids were formed as the successive metabolites of lactic acid. Of the three organic acids added individually to bottom muds, lactic acid was utilized as hydrogen donor for the sulfate reduction, and acetic and propionic acids were produced with the passage of sulfate reduction. Acetic and propionic acids were not utilized for the sulfate reduction, but they were converted into methane, when the degree of sulfate reduction attained more than 80%.View full abstractDownload PDF (2384K) -
A. Kracher, G. Kurat, V. F. Buchwald1977 Volume 11 Issue 4 Pages 207-217
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSA study of accessory minerals in the Cape York iron meteorite has been carried out with the electron microprobe. Phases analyzed include chromite, sphalerite, two closely related potassium-bearing sulfides, silica, and native copper. In addition, four phosphate minerals were found: One chemically similar to buchwaldite, but rather rich in iron, one corresponding to terrestrial maricite, and two more, which seem to be new minerals on the basis of microprobe analysis. Evidence from the composition of accessory minerals as well as texture elucidates some details of the fractional crystallization of the group III AB parent melt. A modification of the fractional crystallization model is therefore proposed. We suggest that sulfide nodules have originated as droplets of an immiscible sulfur-rich liquid that continuously segregated from the parent melt during crystallization of the metal. The modified model also explains the Ni/Cr anticorrelation and the high abundance of sulfur in group III AB irons which could not be satisfactorily explained by previous models.View full abstractDownload PDF (3974K) -
R. G. Downing, E. W. Hennecke, O. K. Manuel1977 Volume 11 Issue 4 Pages 219-229
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSAnalyses of noble gases released by stepwise heating of Josephinite reveal two radiogenic components, radiogenic 129Xe≈ 1 × 10-12ccSTP/g and radiogenic 40Ar≈1×10-6ccSTP/g, and the following components of trapped noble gases: He with 3He/4He≈4×10-5, Ne with 20Ne/22Ne = 10.5, Ar with 40Ar/36Ar = 3×102, and Kr and Xe with isotopic compositions similar to those observed in iron meteorites. The excess of 40Ar and literature values of K in bulk Josephinite yield an apparent K-Ar age of ≈4.6×109 years.View full abstractDownload PDF (3227K) -
R. J. Drozd, F. A. Podosek1977 Volume 11 Issue 4 Pages 231-237
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSThis paper describes the methodology of iodine-xenon dating of meteorites, the assumptions involved in this methodology, and possible failures of these assumptions. Particular attention is given to the case of the Arapahoe meteorite, in which DROZD and PODOSEK (1976) have reported the existence of trapped xenon with 129Xe/132Xe = 0.56, an interpretation disputed by KURODA (1976). We conclude that the conventional interpretations of iodine-xenon dating are valid, although objections to these interpretations cannot be rigorously dismissed.View full abstractDownload PDF (2621K) -
Brian L. Gulson1977 Volume 11 Issue 4 Pages 239-245
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSIn the volcanogenic Woodlawn Cu-Pb-Zn deposit, where pyrite is the dominant sulphide phase in the ore and a ubiquitous mineral in the host volcanics and shales, leaching experiments using HNO3-HCl to overcome the ore/rock lead dominance, resulted in highly complex lead isotopic data, dependent mainly on the original lead concentration in the rock. For samples with higher (> 5 ppm) lead concentrations, the acid leaches are less radiogenic than the rocks or residues whereas for samples with < 5ppm lead, the acid leaches are more radiogenic than the rocks or residues. In those samples with > 15 ppm lead, the data arrays are those expected for a dominance of ore/rock lead. In all except the very high lead samples (> 100ppm), lead is derived from sources other than sulphides. Furthermore, in only the highest lead sample is the acid leach isotopic value compatible with that of the ore lead. As found in previous leaching investigations, the dominant component of lead and uranium is extracted in the acid leach. Acid-leaching experiments of this type may have possible applications in prospecting for basemetal sulphides.View full abstractDownload PDF (1882K) -
Seiji Yuasa, Masahiro Ishigami1977 Volume 11 Issue 4 Pages 247-252
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSPolycondensation of HCN was investigated using divalent metal compounds such as MgO and MgCO3 which are available in the earth and in extraterrestrial bodies, e.g. chondrites. It was known that the above compounds were effective for the condensation of HCN and played the same catalytic function as ammonia. In the present system, the reaction product mixture gave diaminomaleonitrile and heterocyclic compounds in addition to amino acids. This paper is intended to propound a possible geochemical aspect of such catalytic compounds in an abiotic synthesis of organic compounds.View full abstractDownload PDF (1497K) -
Rodney H. Grapes1977 Volume 11 Issue 4 Pages 253-255
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSRoutine EPMA analyses of homogeneous amphiboles in amphibolites indicate significant compositional variation between sections with two cleavages and those with a single cleavage parallel to the c axis. Sections with two cleavages are enriched in SiO2, MgO, MnO and CaO relative to sections with a single cleavage which are enriched in Al2O3, FeO(total), TiO2, Na2O, and K2O (i.e. ∑ of tschermakiteedenite substitutions). The degree of compositional variation between the different amphibole sections may, in part, be related to the extent of equilibrium attained in the rocks during recrystallization.View full abstractDownload PDF (823K) -
M. B. Gavini, P. K. Kuroda1977 Volume 11 Issue 4 Pages 257-260
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSThe concentrations of 238Pu and 239, 240Pu were measured in surface air and rain samples collected at Fayetteville (36°N, 94°W), Arkansas, during the period between October 1971 and November 1973. The 238PU/239, 240Pu ratios in many of the samples were found to be in the range between 0.1 and 0.3. These results indicate that appreciable amounts of 238Pu are being injected into the atmosphere by the recent nuclear weapons tests.View full abstractDownload PDF (972K) -
Jun Sato, Kazuo Sato1977 Volume 11 Issue 4 Pages 261-266
Published: December 20, 1977
Released on J-STAGE: September 26, 2008
JOURNAL FREE ACCESSSeveral suites of volcanic rock samples from Japan are investigated by non-destructive gamma-ray spectrometry. Each suite consists of a variety of rock types from a single volcano. The individual volcanoes show a variation in both Th and U series specific activities which parallels the change in K content. Strong coherence between Th and U series activities is also present. A detailed examination of three types of plot, Th series vs. U series, Th series vs. K and U series vs. K, reveals that each volcano has a characteristic pattern. It appears that gamma-ray spectrometric data can be used to distinguish between products from different families of magma.View full abstractDownload PDF (1566K) -
Yoshito Matsui1977 Volume 11 Issue 4 Pages 267-268
Published: December 20, 1977
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSDownload PDF (640K)
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