The Journal of the Geological Society of Japan
Online ISSN : 1349-9963
Print ISSN : 0016-7630
ISSN-L : 0016-7630
Volume 56, Issue 659
Displaying 1-4 of 4 articles from this issue
  • Koiti Suzuki
    1950 Volume 56 Issue 659 Pages 383-397
    Published: October 15, 1950
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    In this paper, there is given a historical review of the recent stratigraphical classification that is standing on the dualismic conception as the lithological and chronological divisions are to be separated distinctly from each other., A short discussion is offered on the scientific and social backgrounds of this dualismic conception in the process of its birth and development., This dualismic conception has the intimate relation with the geometric conception or formalism which dominated from the time of Aristoteles, even in the world of sciene., This conception supports unconciously the principle of geometric extension, that is to say the distribution of the material observed in detail on the surface of the earth may suggest the undeerground extension of it., The practical experience, however, denies it., The distribution of materials on the earth, is subjected to the geological movement that concentrates, transports, deposits or decomposes all the materials of the earth., It is clear, then, that the observed distribution of the materials never warrants the underground extension of them, but only the geological movement of the earth, nallow or broad, traced and substituted from the relations among the materials distributed there, can show the underground distribution precisely., This is why the writer and Miss U., Kitazaki proposed lately the geohistorical classification of the strata, synthesizing the lithological and chronological classifications.,
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  • Tokio Shikama
    1950 Volume 56 Issue 659 Pages 399-406
    Published: October 15, 1950
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    As the time-stratigraphical units of the Japanese Quaternary, the writer here proposes 12 units in ascending order, namely, 1 (I 1) Akasian, 2 (I 2) Sanukian, 3 (J 1) Makutian, Sematian, Naritian, 4 (J 2) Manzakian, Nisiyagian, 5 (J 3) Iwazikuan, Tatikawian, Ekotian, 6 (K 1) Numian and 7 (K 2) Yurakutyoan., The last two belong to Holocene., The later half of the Akasian perhaps may be regarded to belong to Villafranchian or the Gunz ice age., The Akasi Group represented by Metasequoia and Parastegodon is probably Astian in age., J 3 corresponds generally to Wurm ice age and Iwazikuan carries lithic culture of Aurignacian type., Nisiyagian represented by the namadicus-occidentalis-Sinomegaceroides (Japanese Megacerid ) fauna and characterized by Palaeoloxodon aomoriensis has close relationship with the eminent terrace-making (Du 1-M) happened after the Manzakian cold age., In the South Kwanto, J 1 is the age of transgression, while in the large parts of Japan J 2 and J 3 is known as the land age., Noteworthy is the Ekotian, top of the Japanes Pleistocene, characterized by Larix flora which indicates the climatic condition same as those of the present median high mountainland of Japan about 10002000m high above sea level., Remains of some alpine flora are found from several localities, about 4580m high above sea level., Sanukian, represented by Stegodon orientalis, occupies the lowest part of the Japanese Pleistocene.,
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  • Yotaro Seki
    1950 Volume 56 Issue 659 Pages 407-412
    Published: October 15, 1950
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    Ultrabasic rocks exposed in Miyamori district, 16km E of Hanamaki-machi, Iwate Prefecture, is intruded by granodiorite on its western side., The metamophic effect of the acid intrusive is seen in a zone about 24km wide along the contact., In this zone, diopside-hornblende rock, a member of the ultrabasic complex, occurs as parallel dikes cutting serpentinized dunite., In the latter rock, porphyroblasts of tremoliteactinolite have been formed by the metamorphism, while the former rock has been converted to the following rock types : 1, Grossularite-basic plagioclase rock (sometimes with epidote and hedenbergite) 2, Bluish green amphibole-biotite rock 3, Biotite-bluish green amphibole-acidic plagioclase rock The first type is characterized by richness in Ca, the second by that in K, Mg and Fe, while the third by that in Na, Fe and Mg (see Fig 6)., It is concluded that these changes have been brought about by combined metasomatism and metamorphic differentiation ; Al, K, Na and Si having been introduced to the diopside-hornblende rock while Fe, Mg and Ca having migrated within the same rock mass.,
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  • [in Japanese]
    1950 Volume 56 Issue 659 Pages 413
    Published: October 15, 1950
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
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