地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
84 巻 , 5 号
選択された号の論文の7件中1~7を表示しています
  • 井関 弘太郎
    1975 年 84 巻 5 号 p. 247-264
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    Alluvial plains in the coastal regions of Japan are considered to have developed according to the following processes : during the last glacial stage when the sea level was lowered, rivers dissected their valleys downward to that level. After then, in consequence of the postglacial rise of the sea level, these valleys were drowned and were filled up with Flandrian deposits.
    The bottom floors of such buried valleys are mostly found at 30-80 meters below the present sea level. These bottom floors in many cases are covered with fluvial gravel beds about 10-20 meters thick. Such gravel beds are mostly overlaid with sediments of finer materials which deposited in the shallow sea during the late and post glacial transgression. They are called “Basal Gravel Beds” of the Recent deposits by the present author. They have probably been formed when the lowering of the sea level reached the limit during the last glacial stage. The huge accumulation of gravels as the Basal Gravel Beds might have been brought on by the overloaded streams which carried much detritus as the production of the strong physical weathering under glacial or periglacial conditions during the Ice Age. The author found that some of the Japanese alluvial fans of a large scale are formed by Recent Basal Gravel Beds.
    The maximum accumulation of the ice during the last glacial stage should be enough to cause a lowering of the sea level of about 80-15 meters below that of the present. In order to get a acceptable figure regarding the lowering of the sea level or the lowest sea level during the last glacial stage, the author, presuming the figures-100 and-140 meters as the postulated low sea level stand, examined the depth of these floors of buried valleys, respectively.
    Based on the results of borings which were carried out with 21 major buried valleys in Japan, the depth from the surface of present-day alluvial plain to the upper face of Basal Gravel Bed which covered bottom floor of buried valley was measured in each alluvial plain and then the relation between the depth of the deepest bore hole and the distance from the mouth of the old valley to that bore hole site was investigated (Fig. 3 and 4). The correlation coefficient between the depth and distance was also calculated.
    Fig. 3 indicates the case in which the sea level was presumed to be 100 meters below that of the present and Fig. 4 in the cases of-140 meters, respectively. Is is obvious from these two charts that the depth of the deepest bore hole negatively correlates with the distance from the mouth of buried valley to that bore hole site. So far as the correlation coefficients are concerned, being-0.870 and-0.890, respectively, the presumed figure of the latter seems to be more acceptable than that of the former. Therefore, judging from the depth of buried valley floors, the author is of the opinion that the figure-140 meters as the lowest sea level during the last glacial stage should be more acceptable than that of-100 meters.
  • 鈴木 秀夫
    1975 年 84 巻 5 号 p. 265-276
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    A small group of Kirisitan (Christian) has miraculously survived in Japan despite the severe oppression in Tokugawa Period. While the majority of Japanese used a lunar calendar, only these Kirisitan fishers knew Gregorian Calendar introduced by Portugese missionaries. During the oppression time their christianity has transformed into a polytheistic religion. Even so they have kept and used their calendar until today for their services with a day's delay from the Gregorian Calendar.
    Through this solar calendar, they have experienced that on their Christmas Eve, 23 rd of December, heavy storms often began, followed by calm days on 26th and 27th. These storms are confirmed by Fig. 1 to be the winter monsoon from Siberia and the calm days to be the result of the weakening of the Siberian High (Fig. 2).
    A problem arises whether these Kirisitans have discovered this “Christmas Storm” by themselves or they have learnt it from Portugese missionaries four hundred years ago. For it is possible that the Portugese missionaries knew something about the Portugese weather on these days of which equivalent is known in Germany as Wheinachtstauwetter (Christmas Bad Weather).
    Such a oversea spread of weather knowledge seems to be possible through a case study on the west coat of South America, where fishers know Viento de San Juan (Wind of St. John) etc which are not supported by the local meteorogical observations. In this case a spread from Spain seems to be probable.
    On the other hand, some of Japanese fishers have used a lunar calendar even until today with several knowledges on lunar singularities such as “8 th's Storm” etc. Against my working hypothesis that such knowledges reflect local weather differences, the distributions of lunar weather knowledges are almost uniform throughout Japan except “Daishiko Storm” and “Daishiko Calm” on 23rd of XI Month (Fig. 3 and 4).
    This uniformity may indicate that a spreading played more important role in the aquirment of weather knowledges than discovery. Since some similarities in lunar weather knowledges are found in Korea and Taiwan a spread from the mainland of China is possible.
    By such considerations a spread of “Christmas Storm” from Portugal still remains a possible guess. Informations from Portugal are most welcomed.
  • 土井 重彦
    1975 年 84 巻 5 号 p. 277-285
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    最近の交通地理学の研究は地域の空間的組織, つまり空間的構造と空間的過程を解明する一側面として進められている。その多くは交通網に関するものであり, とりわけその連結性と結節点の相対的近接性を測定し, 評価するといつた網全体および結節点の諸性質の分析に焦点をあてている。しかし, 交通網の一方の構成要素である連鎖線の性質に関する分析は上記の2分析と同様に重要であるにもかかわらず, ほとんどなされていない。この分析に基礎を与えるのは, 交通網内での連鎖線の相対的重要性を測定, あるいはそれを階層的に分類することであると考える。それによつて連鎖線に関連した一連の分析が計量的に処理可能となろう。
    このような階層的分類のシステム化はいくつか試みられている。たとえば, WALLACE (1958), KISSLING (1969), アメリカ合衆国交通局 (1969), 建設省 (1972) 等がある。それらはいずれも複雑な交通流のデータと計算を要求しており, 実際には非常に困難な問題をともなつているのが常である。ところで, 地形学, 水文学で用いられている水流次数化システム (榧根, 1973) を直接的に応用することによつて, 比較的単純に交通網の連鎖線を階層的に分類することが可能となることを示したのがHAGGETT (1967) とRIDDELL (1973) である。それらはいずれも強力な単一の結節点に着目しての分類システムである。しかし, 実際の交通網は水系網に比べて, いつそう複雑であり, 複数の結節点を持つている。
    そこで, 本論では水流次数化システムをさらに拡大することによつて, 複数の結節点を含んだ地域的道路網の連鎖線を階層的に分類するシステムを提示する。また, このシステムを実証する意味で, 階層化された連鎖線と交通流の関係を, 静岡西部地域の道路網を例に述べることにする。
  • 前田 四郎, 山際 延夫, 北村 健次, Leonardo BRANISA, Mario URDININEA
    1975 年 84 巻 5 号 p. 286-293
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    The Copacabana group distributed between the two ranges of the Andes Oriental and the Andes Occidental in the central part of Bolivia represents one of the standard stratigraphic sequences of the upper Palaeozoic sediments in Central Andes. In 1973 the writers carried out the geological reconnaissance at the Colquencha area, Altiplano, paying special attention to that group. The Palaeozoic formations in this area consist of Silurian, Devonian, Carboniferous and Permian systems, the last of which is called as the Copacabana group. The group estimated about 300 m in thickness is well exposed at the northeastern foot of mountainland near Colquencha. It lies conformably on the Carboniferous system consisting of the alternation of sandstone and shale. The group is mainly composed of fine-to coarsegrained reddish sandstone, black or dark grey shale and dark or reddish limestone. Its lower part is dominated by massive sandstone, and the upper part by the alternation of sandstone, shale and limestone. The limestone contains such fossils as Brachiopods, Gastropods, Fusulinids, Corals, Crinoids, Bryozoans and so forth with calcareous or siliceous angulated nodules.
    The writers found Pseudoschwarina, Schwagerina, “Rugosofusulina” and other fusulinaceans from the upper-most horizon of the group in this area. Judging from these fossil evidences, it is thought that the upper-most horizon of the group assigns to the Lower Permian. The geological structure of the Palaeozoic strata is characterized by a syncline with axis running NNE-SSW and by the faults of NW-SE. The deformation of the Palaeozoic strata might had been completed before the Tertiary sediments were deposited.
  • 岡野 武雄
    1975 年 84 巻 5 号 p. 294-301
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 河村 武
    1975 年 84 巻 5 号 p. 302-303
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小泉 武栄
    1975 年 84 巻 5 号 p. Plate1-Plate2
    発行日: 1975/10/25
    公開日: 2009/11/12
    ジャーナル フリー
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