The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists
Online ISSN : 1883-0765
Print ISSN : 0021-4825
ISSN-L : 0021-4825
Volume 43, Issue 5
Displaying 1-6 of 6 articles from this issue
  • Kokichi Okada
    1959 Volume 43 Issue 5 Pages 229-238
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
    Manganese dioxide mineral from the Iwasaki mine was examined by means of X-ray powder method and D. T. A, and the following results were obtained.
    (1) The X-ray pattens are similar to Cole's γ-MnO2I. Accordingly, the manganese mineral from the Iwasaki mine is defined to γ type ramsdellite.
    (2) The D. T. A. curve of γ type ramsdellite consist of three peaks which are accompanied with exothermic peak at 370°C, and endothermic peaks at 600 and 980°C. The exothermic peak is phase change from γ-MnO2I to β-MnO2, two endothermic peak are reduction of β-Mn2→Mn2O3 and Mn2O3→Mn3O4.
    (3) A γ type ramsdellite is spreaded distribution in Japan, and some examples were given.
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  • Hirosi Abe
    1959 Volume 43 Issue 5 Pages 239-247
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
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  • Ken-ichiro Aoki, Hatao Matsumoto
    1959 Volume 43 Issue 5 Pages 248-253
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
    Kaersutite is often found in trachybasalts, trachyandesites, trachytes and alkali rhyolites in the Iki island. Large crystals attainning a length of 3cm. are included in scoria from Takenotsuji and in lava flow from Numazu. The chemical compositions and optical properties of phenocrysts in Numazu and Takenotsuji and of crystals in cognate inclusions in trachyte at the foot of Kakujo-san are given in Table 2. Total iron of these kaersutites is almost same but a remarkable difference is seen in the Fe2O3/FeO. Kaersutite from Takenotsuji is poor in FeO and rich in Fe2O3 and shows extremely high refractive indices and very strong pleochroism. These facts are considered to be due to remarkable oxidation of kaersutite in the scoria when they were erupted. So the authors intend to propose a name“oxykaersutite”which shows high Fe2O3/FeO ratio and refractive indices and strong pleochroism.
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  • Studies on the resource-rocks of petroleum (3rd report)
    Iwao Kato, Masahiro Abe
    1959 Volume 43 Issue 5 Pages 254-261
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
    The purpose of the present work is to make a mechanical purification of the cutting samples for detailed chemical and physical investigations of them. 289 cutting samples from Ôguchi exploratory well, R8, in the Nagaoka Basin, Niigata Prefecture were classified according to mechanical analysis, and considerations were made based on histograms, cumulative curves and triangular diagrams drawn on the basis of the size fractions, 8 mesh, 8-9 mesh, 9-16 mesh, and the remainders of the respective samples. The other hand, extractable organic constituents of the 36 specimens selected from these 289 samples were determined.
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  • Kiyoshi Miura
    1959 Volume 43 Issue 5 Pages 262-266
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
    Pisolites, the products of volcanic activities of Sanbe Volcano, are collected from small exposure near Kasubuchi town, Shimane Prefecture. They are composed chiefly of the fragments of quartz, biotite, feldspar, glassy materials and a few hornblende. Quartz and feldspar, occur as in angular granular form, but biotite as in prismatic one. They are found usually as in well-spherulitic form ranging from 1 to 10mm (the maximum attains 13mm) in diameter, but the diameter of 2.5 to 6.5mm is the most predominant, and the form appears as in more or less oblate spheroidal form. Under the microscope, concentric texture is easy to be found in the specimens, in decreasing the size of grains from the core to the margin; i. e. the core composed of coarse-grained fragments is surrounded densely by the margin layer that composed of fine powdered materials.
    Genetically, it is assumed that the pisolites have been formed by coagulation of volcanic ashes around a nucleus or centre of raindrop when it was falling in the air, and the concentric texture due to the change of grain size of ashes is attributed to the change of water content in a growing pisolite.
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  • Nobuhide Murakami
    1959 Volume 43 Issue 5 Pages 267-274
    Published: October 01, 1959
    Released on J-STAGE: August 07, 2008
    JOURNAL FREE ACCESS
    Several types of dike rock can be found in the Hiroshima granite as follows: dolerite, pyroxene-porphyrite and hornblende-porphyrite, lamprophyre, hornblende-quartz-porphyrite, hornblende-biotite-granite-porphyry, biotite-granite-porphyry, fluidal micro-aplitic rock, coarse-grained quartz-porphyry, granophyre, felsite and felsitic quartz-porphry, plagiophyre, and pitchstone.
    In the broadly-distributed normal Hiroshima granite these dike rocks have sharp contacts . In the Yashiro granite which is a coarse-grained biotite-granite bearing porphyritic potash-feldspars, the dikes of spessartite and granite-porphyry are often invaded by aplite and quartz veins, and slightly granitized.
    The genetical history of the Yashiro granite is divided into the stage of magmatic intrusion of main body and later metasomatic replacement. The above-mentioned dikes must have intruded in the later metasomatic stage. The origin of these dikes are quitely unknown, but their original magma would be unrelated with the granite magma.
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