第四紀研究
Online ISSN : 1881-8129
Print ISSN : 0418-2642
ISSN-L : 0418-2642
25 巻 , 1 号
選択された号の論文の4件中1~4を表示しています
  • 讃岐田 訓, 松下 まり子
    1986 年 25 巻 1 号 p. 1-12
    発行日: 1986/05/31
    公開日: 2009/08/21
    ジャーナル フリー
    浜名湖の底質の物理化学的諸性質と湖水中の植物プランクトンの挙動ならびに堆積物中の花粉・胞子の分布について調べた.
    浜名湖は3湖域に区分できる。1) 2つの付属湖を含む主湖北部, 2) 主湖南部, および3) 庄内湖である. 主湖の2つの湖域は湖の中央部を横切る4~8mの等深線で区分される。この線は堆積物の中央粒径値 (Mdφ) 4~8ψ, 強熱減量分 (IL) 3~10%, 全炭素1.0~3.0%, 全窒素0.1~0.3%の等値線とほぼ一致する。それらはまた, 凍結乾燥泥1g当たりの花粉・胞子数104~5×104粒の等値線とも一致する。主湖北部と同程度の値が, 庄内湖奥部でもみられた. 最高値は主湖北西部および庄内湖奥部で得られた. これはわが国の水界においても最も高い水準に位置づけられる.
    ここでは, 集積が最も顕著である主湖北西部への諸物質の供給源およびその集積過程を植物プランクトンと花粉・胞子を追跡指標として調べた. 主な供給源は都田川流域であり, その豊富な流量の影響により有機物質およよび花粉・胞子は引佐細江湖を通って主湖北部へと運搬され, 集積する. これを惹起する主な要因としては, 成層形成による垂直混合の欠落, 底層での外洋水の流入および主湖中央部にみられる地形境界の存在が考えられた.
  • 佐々木 昌子
    1986 年 25 巻 1 号 p. 13-19
    発行日: 1986/05/31
    公開日: 2009/08/21
    ジャーナル フリー
    Pollen assemblages obtained from surface samples collected at the seven moors in the different areas of mountain vegetation of central and northern Honshu, Japan, are compared and discussed with reference to the vegetation surrounding the respective moors. The pollen represented within the assemblages consists of two major groups. The first group comprises pollen which may be carried a considerable distance from the source plant. This group appears to be mainly composed of the pollen from the tree layers in forests and to be partially composed of the pollen of herbaceous plants which form the major component of local flora. The second group represents pollen from plants growing locally in the herbaceous or the shrub layer surrounding the moor. These groups are further subdivided into six categories according to whether or not the occurrence is consistent with all the samples studied. It is suggested that these categories may interchange according to the numbers of the source plants, differences in pollen productivity, distance from the source plant, topography of the area, and wind directions.
  • 横山 卓雄, 檀原 徹, 山下 透
    1986 年 25 巻 1 号 p. 21-30
    発行日: 1986/05/31
    公開日: 2009/08/21
    ジャーナル フリー
    A new refractometer, Type Dokf-EK. 85, was made in 1985 by the united efforts of Doshisha University, Kyoto Fission-Track Ltd. and K. K. Eikodenki (see. Fig. 1). It can measure the refractive indices of individual glass flakes at intervals of 1×10-4 under a microscope.
    The index value of refraction follows the temperature change of immersion liquid, which is automatically controlled by the thermo module in this instrument. When the glass flakes in the immersion liquid disappear under the microscope, the operator sends a signal to the microcomputer. After the steps of procedure are repeated about 10 times on a glass flake, the microcomputer calculates its refractive index value as the mean of all measurements.
    The refractive indices of volcanic glass flakes in the widespread tephras which are famous as the makers of datum plane in the Japanese Quaternary such as Akahoya, Aira-Tn, Pink and Azuki Volcanic Ash Layers, were measured. The obtained values from each tepha were well concordant with those in the previous reports (Table. 3).
    This refractometer is useful for the identification of tephras, because it is very easy to measure the refractive indices of many glass flakes, and to discriminate none-essential glass under the microscope, even if they are of a very small amount and are mixed in other kinds of grains such as minerals and pumices.
  • 近藤 錬三, 佐瀬 隆
    1986 年 25 巻 1 号 p. 31-63
    発行日: 1986/05/31
    公開日: 2009/08/21
    ジャーナル フリー
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