All issues
Volume 19 (1985 - 198･･･
- Issue 6 Pages 289-
- Issue 5 Pages 251-
- Issue 4 Pages 181-
- Issue 3 Pages 113-
- Issue 2 Pages 59-
- Issue 1 Pages 1-
Volume 19, Issue 2
Displaying 1-8 of 8 articles from this issue
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Kiyoshi Kaneshima, Hatsuo Taira, Yasushi Kitano, Akira Takaesu, Seizen ...1985 Volume 19 Issue 2 Pages 59-67
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSRainbow stone, or colored limestone consists of four portions which differ in its color and chemical composition. They are black colored portion due to manganese dioxide (micro-manganese nodules), reddish brown portion due to iron oxides, pale yellowish pink portion due to aluminosilicate and some other compounds, and white portion due to calcite and/or proto-dolomite. The color of Rainbow stone is controlled mainly by Fe2O3 and MnO2 contents. Electron probe micro analyses (EPMA) clarify the existence of micro-manganese nodules in the black portion with iron oxides in its nucleus. Rhombohedral crystals of dolomite are observed with calcite. NaCl crystals, which are confirmed by X-ray diffraction analysis and EPMA, are incorporated into proto-dolomite almost regardless of its color. This shows that proto-dolomite on Daito Islands could have been formed through the evaporation of concentrated sea water.View full abstractDownload PDF (3063K) -
Hatsuo Taira, Yasushi Kitano, Kiyoshi Kaneshima1985 Volume 19 Issue 2 Pages 69-76
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSSelective chemical leaching technique has been applied to the study on the partitioning of major and minor constituents into individual mineral species in ferro-manganese nodules formed in limestone areas of the Ryukyu Islands. The technique includes the use of 25% CH3COOH, 1 M NH2OH·HCl-25% CH3COOH and 30% H2O2 solutions. Treatment with 25% CH3COOH solution led to the leaching of 51% of Ca, 0.6% of Fe and 1.5% of Mn. Successive leaching with 1 M NH2OH·HCl-25% CH3COOH solution led to the leaching of 32% of Fe and almost 100% of Mn. The rate of leaching is largely dependent on the mineral components in the nodules. Minor elements are concentrated in the ferro-manganese fraction which is leached with 1 M NH2OH·HCl-25% CH3COOH solution. The rate of leaching is 100% for Co, 93% for Cu, 87% for Pb, 82% for Cd, 76% for Ni and 45% for Zn. Some parts of the elements remained insoluble in the above solutions. The remained fraction may have been associated with either stable clay lattice structure or stable oxide forms of lithogenous origins.View full abstractDownload PDF (2380K) -
Shizuo Tsunogai, Takayoshi Shinagawa, Takayoshi Kurata1985 Volume 19 Issue 2 Pages 77-90
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSThe monthly deposition rates of sodium, calcium, chloride, sulfate and Pb-210 from the atmosphere were measured at 12 stations in various parts of the Japanese Islands for two years. The deposition rates of sea salt particles were higher in the coastal region near the Sea of Japan in winter, demonstrating the fact that the strong winter monsoon produces many sea salt particles. Amounts of chloride, sulfate and calcium in excess of the sea salt component were always observed. The rather uniform annual deposition rates of excess sulfate (3–10g/m2/y) suggest that a large part of this excess sulfate originates in global air pollution. Pb-210, much of which is of upper atmospheric origin, is also deposited in significant amounts in winter. This seasonal change may be due to the replacement of lower air masses over the continental margin area, which yields a two-layer model for the atmospheric transport of chemical constituents. The geographical variation of Pb-210 deposition can be explained using the two-layer model and by assuming a 12 day residence time for the tropospheric aerosols. The deposition rates for sulfate over the ocean area decrease more rapidly with distance from the continental coast than those for Pb-210. This result may show that the atmospheric residence time of sulfate is shorter than that of Pb-210.View full abstractDownload PDF (2944K) -
Genki I. Matsumoto, Tetsuya Torii, Takahisa Hanya1985 Volume 19 Issue 2 Pages 91-96
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSSterols and fatty acids were studied for foam samples from lakes of Wright Valley in the Dry Valleys of south Victoria Land, Antarctica. Sterols, 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-ethylchlesta-5, 22-dien-3β-ol, 24-ethylcholest-5-en-3β-ol and 5α-cholestan-3β-ol, and fatty acids ranging from C10 to C28, including n-alkanoic, branched (iso and anteiso) and unsaturated acids were found in the foam samples. The dominant sterol was cholest5-en-3β-ol or 24-ethylcholest-5-en-3β-ol. The sterol and fatty acid compositions of the foam samples are similar to those of epibenthic organisms (mainly cyanobacteria). The sources of the sterols and fatty acids are most likely cyanobacteria. In addition, these lipid components were concentrated considerably in the foams.View full abstractDownload PDF (1468K) -
Ken'ichi Nogami, Kazuo Yamakoshi1985 Volume 19 Issue 2 Pages 97-99
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSFor the purpose of estimating the degree of evaporation loss of cosmogenic nuclides in the ablation products of materials by atmospheric heatings, a few laboratory ablation experiments were performed. Small Fe and Ni metal chips in which radioactive 54Mn, 51Cr and 58Co were induced by fast neutron irradiation, were heated to 10–20°C above the melting point under 40mtorr air pressure. Gamma ray activities of the radionuclides measured before and after the heating show that 54Mn evaporates much faster than Fe, 51Cr and 58Co evaporate much slower than 54Mn, but faster than the major elements, Fe and Ni.View full abstractDownload PDF (785K) -
Ken'ichi Nogami1985 Volume 19 Issue 2 Pages 101-105
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSA melting experiment was performed to simulate the ablation process of the meteoroids. Small pieces of the Henbury iron meteorite and two kinds of alloys were melted in electric crucibles placed in a low air pressure chamber. The temperature was kept 20°C above the melting point of each sample for 1 to 30min. The residues of the Henbury meteorite were analyzed by instrumental neutron activation analysis (INAA) for Fe, Co, Ni, Ga, As, Ir and Au, and those of Ni and Fe alloys were analyzed by electron probe micro analyzer (EPMA) for Si, Cr and Fe, and Si, respectively.View full abstractDownload PDF (1332K) -
P. K. Kuroda1985 Volume 19 Issue 2 Pages 107-112
Published: 1985
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSIsotopically anomalous nitrogen and carbon found in the carbonaceous chondrites Allende and Murchison can be attributed to the x-process nucleosynthesis, which produced, aside from the light elements D, Li, Be and B, appreciable quantities of 12C, 13C, 14N, 15N, 16O, 17O, 18O and so on during an intermediate stage in the early history of the solar system.View full abstractDownload PDF (1866K) -
1985 Volume 19 Issue 2 Pages e1
Published: 1985
Released on J-STAGE: February 06, 2009
JOURNAL FREE ACCESSDownload PDF (319K)
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