Earth Science (Chikyu Kagaku)
Online ISSN : 2189-7212
Print ISSN : 0366-6611
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Volume 21, Issue 3
Displaying 1-8 of 8 articles from this issue
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  • А.Т.Бетехтин
    Fumio KISHIMOTO
    Article type: Article
    1967 Volume 21 Issue 3 Pages ii-iii
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_ii
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  • Kurofuji Volcano and its Volcano-Stratigraphy, Central Japan
    Koji MIMURA
    Article type: Article
    1967 Volume 21 Issue 3 Pages 1-10a
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_1
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    Kurofuji volcano of the Lower Pleistocene in age stands at the northern margin of the Kofu basin, Central Japan. The products of that volcano cover an extensive area more than 217 km2, and are characterized by the presence of ash-flow fields of large scale and radial dikes. The products of that volcano consist of the Kurofuji pyroclastic flows, the Kurofuji Dikes and the Kayagatake lavas in order of eruptive activity. The first, the Kurofuji pyroclastic flows of dacite which occupied more than 32.5 km3 in total volume had been brought by fissure eruption(F). They are divided into five units by litho-facies, each of which consists of multiple-flow compound cooling units. Therefore, the activity of the pyroclastic flows is classified into five stages and is characterized by less pyroclastic falls and no lava flow. Succeeding to that activity, the Kurofuji dikes had built up many domes of dacite at the central area of the preceding pyroclastic flows effusion. Nowadays, the dikes display a typical radial pattern due to the severe dissection. The last, the Kayagatake lavas which form a small strato-volcano on the western slope of Kurofuji volcano had been derived mainly from the central eruption of two-pyroxene andesite.
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  • Discussion on the Two-dimensional Morphometry of Fault Scarps
    Masashige HIRANO
    Article type: Article
    1967 Volume 21 Issue 3 Pages 11-21
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_11
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    Two-dimensional morphometry of fault scarps is attempted and the results are compared with the solutions derived from the mathematical model of slope development. For this purpose, average height of the slope in the sections parallel to the fault is calculated from the elevations read at the points settled with a constant interval in each section. Though the average height obtained by this method is regarded to be a function of the distances measured from the fault, its fluctuation can be compared with that of the theoretical values derived from the model. In addition, it may be concluded that standard deviation of the elevations in each section can be an estimate of the velocity of height decrease of the slope there. It is also considered to be possible to investigate the recent movement of the fault from data by the morphometry.
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  • The Absolute Age of the Oshio Pyroclastic Flow, Yatsugatake
    14C-Age of the Quaternary Deposits in Japan XXXII
    Shimpei KAWACHI, Kazuo KITAZAWA
    Article type: Article
    1967 Volume 21 Issue 3 Pages 21-22
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_21
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  • Some Characters of Pyrite Crystals from Kitami Mine, Hokkaido
    Keiichi YAMADA
    Article type: Article
    1967 Volume 21 Issue 3 Pages 23-33
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_23
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    In this paper, we have described on some characteristic features of pyrite crystals from the main ore veins of Kitami mine, especially on the variations of grain size, crystal form and etch figures. The pyrite crystals show the various mode of occurrences in this mine, as single crystal in the druse or as massive aggregate in the main parts of ore vein associate with other sulfide minerals and as a simple ore vein which consists of pyrite only. According to those occurrences and to the stages of metallization processes, the pyrite show the regular variations of its grain size, crystal form and etch figures. Generally, the ore veins in this mine are composed of some unit vein which shows the characteristic mineral assemblages of early to later stages of metallization processes. Early stage : Chlorite-quartz vein with no othei sulfide minerals. Pyrite ocurres as single crystal fine grain and cube in form, rarely octahedral and etch figure of tetra gonal without any other special figures. Middle stage (a): Pyrite-chalcopyrite vein or pyrite-pyrrhotite-sphalerite vein with small amounts of bismuthinite, cubanite etc., Pyrite: Loose aggregate and shows rough crystal form, mainly cubic. Grain size are more or less coarser than ealier one. Etch figures are mainly tetragonal same as early, but the two or three figures in one crystal. (b): Buartz-sulfide vein, carbonatesulfide vein with many exsolutioc textures. Pyrite: Massive and no definite crystal form. Grain size are coarser. Etch figures are complicate, tetragonal, trigonal and pentagonal form are common. Sometimes those figures presents in one crystal. (c): Quartz-pyrite vein or pyrite vein with very small amount of other sulfides. Pyrite: Massive with no grain boundary and crystal form, coarse gain. Etch figures are granular, tetragonal, pentagonal etc., Later stage : Carbonate-sphalerite-sphal erite-pyrite in druse. Pyrite : Mainly single with beautiful faces, rarely natural etch figures on the surface. No react to etching or very difficult.
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  • Influence of the “Sangun-metamorphism” on the Maizuru Structural Belt, Japan
    Sachio IGI
    Article type: Article
    1967 Volume 21 Issue 3 Pages 34-38
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_34
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    The Permian “Schalstein” in the Maizuru structural belt, as well as the mafic pyroclastic rocks in the Sangun metamorphic belt, at Kami-ishii, Sayo-cho, Hyogo Prefecture, has suffered the low grade regional metamorphism. That is, the basic pyroclastic rocks of both belts were altered into the metamorphic rocks with the mineral assemblages of the prehnite-pumpellyite metagraywacke facies. This fact suggests that the so-called “Sangun metamorphism” has affected not only the Sangun metamorphic belt, but also the Maizuru structural belt.
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  • The Pre-Cambrian Age
    Hideo KOBAYASHI
    Article type: Article
    1967 Volume 21 Issue 3 Pages 39-46
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_39
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  • The Absolute Age of the Eruption of the Maebashi Mud Flow and the Iwajuku 1-st Stage
    14C-Age of the Quaternary Deposits in Japan XXXIII
    Fusao ARAI
    Article type: Article
    1967 Volume 21 Issue 3 Pages 46-iii
    Published: May 25, 1967
    Released on J-STAGE: July 26, 2017
    DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.3_46
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