Journal of Geography (Chigaku Zasshi)
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
Volume 64 , Issue 3
Showing 1-6 articles out of 6 articles from the selected issue
  • Kazue WATANABE
    1955 Volume 64 Issue 3 Pages 71-86
    Published: September 30, 1955
    Released: November 12, 2009
    1) All geological phenomena in research works reveal its substance according to the sharp conceptions concerning its stratigraphical position and structural aspect. Especially, younger sediments, Neogene Tertiary, have more intricated forming process and interbed highly evoluted flora & fauna, therefore its stratigraphical subdivision meets accelerated difficulties along with the advance of geologic times. On this account, the geochemical criteria, i. e. -pleochroic halos or radioactivity, and the keybed probation have considerably been available to explain the geologic system. Above all the age determination method of C14 ratio is the epoch-making discovery, in this century, but its applicable scope is about 30, 000 years. And its accuracy has often given rise to discussion from the stratigraphical view point. Recently Ernst Antevs discusses this problem in the report. (Jour. of Geology, Vol. 61, No. 3, 1953, p. 195-230) Another excellent works were published by W. D. Urry in 1949 by the tool of the “percentage of equilibrium method” for uranium, ionium, and radium. (ibid.p.252-262) But this method has its applicable scope of 300, 000 years. Setting aside this scope problem, these contributions have surely been valid to make the rigid progress of the earth science.
    2) The author has recently established the age determination method, that is, as stated above, “the percentage equilibrium method” for organic carbon. (K. Watanabe : The chronological significance of coal, Bull. Geol. Surv. Japan., Vol. 2, No. 8, 1951) In 1953, this device was reasonably appreciated by Dr. D. W. Van Krevelen, Director of the Central Research Laboratory in Holland. Thereafter this method has greatly been improved by making a comparative study with C14 method (three Japanese specimens, No. 629, 548, 603, determined by Libby were used.). These are considerably satisfactory results to the effect that they are not absolute but relative, Needless to say, this organic carbon method has a chronological index -θ (0°-180°), ranging from the present time to Carboniferous period or so on. Accordingly he applied this method to 76 specimens from Kuwana district. (Table 2, Fig. 3). These specimens have various indices ranging from 0.2° to 5.9° (3, 000 years-12, 600, 000 years; recent?upper Miocene). Synthesizing these data, he has drawn the new map, -Isogeochronological map of Kuwana. (Fig. 4) Of course these indices have performed a rôle of the correlative tool and manifested several new geologic phenomena which had not been found before. He can show them as follows ;
    (1) Synchronous bed with the Chigusa member (marine sediments) exclusively depositing on the side of the Suzuka mountains has been detected on the other side of the Yoro mountains as a member of the terrigenous deposits.
    (2) The tentative boundary between Tertiary and Quaternary has quantitatively been determined.
    (3) A presumptive fault or folding A-B has been found out by recognizing the uncontinuous zone of θ-Isohypsen.
    (4) Both structural basins (Machiya system and Asaka system) have contracted drainage areas downwards by upwarping movement at the coastal plain.
    (5) Collectively all geologic displacements and fluctuations can quantitatively be measured.
    3) Applied geology of this region.
    (1) Porcelain clay or other lower class clay.
    By organic carbon method of age determination, synchronous strata with ones interbedding good porcelain clay (kaolinite-rich) at Seto, Tajimi, have been detected in this region, -Minami-Nakatsuhara, Tado, Oharaisshiki etc, but its quality is not so good as those porcelain clay. On the contrary, the Chigusa marine bed is rich in montmorillonite or illite minerals. All other lower class clay can be traced their origins and occurrences by Fig. 4 chart from the environmental or genetic point of view. (cf. Fig. 5)
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    1955 Volume 64 Issue 3 Pages 87-95
    Published: September 30, 1955
    Released: November 12, 2009
    1. The Relation of the Type of Test-piece and its Bearing-power
    It is important problem that bearing-power of foundation rocks on civil engineering.
    The writer tried to make the test-piece of rocks and destroyed under compressive-testing-machine, for the measure sake of destroying point on the unit area, and found the standard type of the test-piece.
    These experimental samples are sandstone and quartz diorite.
    It was found the difference of bearing-power of the test-piece relate to the alteration of height each of circular-cylinder-type, and tetragonal-prism-type.
    Consequently, he think that it was right to determine the standard type that the circular-cylinder-types are L/D = 2 (L = length, D = diameter), the tetragonal-prism-types are H/D = 1 (H = Height, L = length of tetragonal).
    2. The Relation between Size of Cubic Test-piece and these Bearing-power
    The writer tested the influence of bearing-power by the variation of size of cubic test-piece.
    The experimental samples are three kinds of quartz diorite occurred in Mt. Mitoyama, Tokyo.
    The writer tried the bearing-power examination on the variation of size from these samples, and got the most reasonable size.
    Consequently, he found that the fittest size of cubic test-piece is 6 cm. cube.
    Besides, he found it was hardly different that the value of bearing-power on same load-surface both of cubic, and circular-cylinder-type.
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    1955 Volume 64 Issue 3 Pages 96-102
    Published: September 30, 1955
    Released: November 12, 2009
    As a member of the party investigating the head district of the Tone River, the writer surveyed the area between the Sudagai Dam to Mt. Otonedake along the valley of the mentioned river, as shown in the geological map. The geological formations developed along the valley are as follows in descending order :
    Mesozoic Okutone Group
    4. Higashimatazawa formation : chiefly of shale and sandstone, associated with thin limestone at places. Molluscan fossils occur.
    3. Kengakurasawa shale shale predominating.
    2. Idozawa sandstone : an alternation of sandstone and shale predominating.
    1. Minagasawa shale : shale predominating.
    From the Higashimatazawa formation the writer collected some molluscs, which H. Fujimoto and Y. Yabe determined as Entomonotis cf. ochotica (KEYSERLING), and its variety var. eurachis (Teller) from Loc. 17 T, and Entomonotis tenuicostata KOBAYASHI and ICHIKAWA and its variety var. mabara KOBAYASHI and ICHIKAWA from Loc. 192.
    The evidence afforded by the fossils indicates that the Higashimatazawa formation is upper Triassic in age.
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  • [in Japanese], [in Japanese]
    1955 Volume 64 Issue 3 Pages 103-104
    Published: September 30, 1955
    Released: November 12, 2009
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  • [in Japanese]
    1955 Volume 64 Issue 3 Pages 105-116
    Published: September 30, 1955
    Released: November 12, 2009
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  • [in Japanese]
    1955 Volume 64 Issue 3 Pages 117-119
    Published: September 30, 1955
    Released: November 12, 2009
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