第四紀研究
Online ISSN : 1881-8129
Print ISSN : 0418-2642
ISSN-L : 0418-2642
8 巻 , 4 号
選択された号の論文の6件中1~6を表示しています
  • 島田 安太郎
    1969 年 8 巻 4 号 p. 111-122
    発行日: 1969/12/31
    公開日: 2009/08/21
    ジャーナル フリー
    The high terraces along the middle course of the Kiso River were investigated with a view to clarify the Quaternary history of the area. It was also expected that the study would contribute towards the history of the Atera fault separating the northeastern mountainous area and the southwestern upland area. Among the terraces studied the following terraces, from the higher to the lower, i. e. the Jizomine, the Kawai, the Uyama and the Goshodaira terraces are described.
    The Jizomine terrace ranges from 900m to 1300m in altitude, and is about 500m high above the present river floor. It is associated with a gravel bed covered with a “loam” bed about 110cm thick. This gravel bed may be correlated with the Toki gravel bed in the lower course of the Kiso River.
    The Kawai terrace, ranging from 880m to 900m in altitude, is 170m to 190m higher than the present river bed. The gravel bed of this terrace contains pebbles of the Jizotoge volcanics which cover the Jizomine gravel bed.
    The Uyama terrace is 670m high, and is 140m higher than the present river bed. The gravel bed of this rerrace is overlain by a 30cm thick “loam”, which, in turn, is covered unconformably by the Wamura mud flow. This gravel bed is correlated with the middle bed of the Akatsuchidaira gravel.
    The Goshodaira terrace is 670m high above the sea level, and the relative height from the present river is 130m. The gravel bed of this terrace, about 30m thick, contains pebbles of the Jizotoge lava as well as those of the Kuragoehara lava, and is overlain ay a bed of the older “loam”. The Uyama and the Goshodaira terraces are considered to be roughly contemporaneous with the older Ontake volcanism.
    The Wamura mud flow covering the Uyama gravel bed is rather thin being three meters. It is easily distinguished from the Kisogawa mud flow in thickness and length of the flow.
    The difference in height of the higher terraces on both sides of the Atera fault suggests that the fault has been active since the earlier part of the Quaternary age.
  • 鈴木 正男
    1969 年 8 巻 4 号 p. 123-130
    発行日: 1969/12/31
    公開日: 2009/08/21
    ジャーナル フリー
    Obsidian is a volcanic glass which was widely used as an important material for making stone implements and found everywhere in archaeological sites all over Japan. As original sources of obsidian are limited to about twenty localities in number, it might be of use to trace the trading area in prehistoric Japan, if the original sources could be determined with regard to obsidian materials found from these archaeological sites.
    The fundamental experiments were carried out for determining original sources of archaeological obsidian materials by means of the age of rock formation and its uranium concentration of the materials. Present paper deals with the results of these experiments together with some results of assays obtained so far on obsidian from several original sources.
    Obsidian samples from four outcrops in Wada-pass in Central Honshu gave almost the same ages of formation (0.85×106yr.) in good accordance with the potassium-argon dates of the same samples. Uranium contents of these samples were also almost the same (6.8 ppm py weight). On the other hand, obsidian samples from Mt. Kirigamine near Wada-pass were clearly different from those of Wada-pass in fission track dates (1.30×106yr.) as well as uranium contents (3.2 ppm by weight)
  • 中西 昭弘, 中川 要之助, 横山 卓雄
    1969 年 8 巻 4 号 p. 131-137
    発行日: 1969/12/31
    公開日: 2009/08/21
    ジャーナル フリー
    In previous papers, it is already recognized that the eight transgressions took place at the Osaka Basin in early Pleistocene Age and that the remarkable continuous clay beds, given the following symbols; Ma 1, ……Ma 8, in ascending order, were deposited in internal bays (ITIHARA: 1960). Recently, TAKETSUJI and ITIHARA (1967) and NAKAGAWA (1967) discovered a marine-like clay bed about 20m. under Ma 1, at the Senriyama Hills and the western part of Nara City.
    The writers carried out the analysis of the diatom flora in order to know the environment in which the marine-like clay bed were deposited. We obtained the following results;
    Osaka Group{Ma 1 marine Ryugaike volcanic ash lacustrine? marine……Coscinodiscus cf. commutatus, Cos. rothii var. normanii, Cyclotella striata etc. Yellow volcanic ash lacustrine……Gommphonema augur, Stephanodiscus niagarae etc. Grey volcanic ash marine……Coscinodiscus cf. commutatus, Cos. rothii var. normanii, Cyclotella striata, Cyc. stylorum etc marine……Coscinodiscus rothii var. normanii, Cycltella striata etc.
  • 若生 達夫
    1969 年 8 巻 4 号 p. 139-141
    発行日: 1969/12/31
    公開日: 2009/08/21
    ジャーナル フリー
  • 1969 年 8 巻 4 号 p. 145a
    発行日: 1969年
    公開日: 2009/08/21
    ジャーナル フリー
  • 1969 年 8 巻 4 号 p. 145b
    発行日: 1969年
    公開日: 2009/08/21
    ジャーナル フリー
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