瀬田・石部地域の古琵琶湖層群

DOI Web Site 被引用文献13件

書誌事項

タイトル別名
  • The Kobiwako Group in the Seta-Ishibe area, southern part of Shiga Prefecture, Japan
  • セデン セキブ チイキ ノ コ ビワコソウグン

この論文をさがす

抄録

The Kobiwako Research Group has made a stratigraphic investigation of the PlioPleistocene Kobiwako Group distributed in the Konan Hills, lying in the southward of Lake Biwa, for the purpose of clarifying the stratigraphic relationships between Minakuchi Hills (Kobiwako Research Group, 1977) and Katata Hills (HAYASHI, 1974). The results of the investigation as to the SetaIshibe area, the eastern part of Konan Hills, are firstly reported in this papar. They are summarized as follows: 1. The Kobiwako Group in this area, having thickness of more than 180 meters, is divided into three Members, namely the Arahari alternations, Asagarano sands and Seta gravels, in the ascending order. Among more than 18 volcanic ash layers found in these members, 13 are available as key beds. They are named Sato, Naritani I and II, Arahari I, II and III, Kiryu I and II, Asagarano, Minogo, Gokenjaya, Shimotoyama I and II, Maruoshinden, Kasayama and Sakuragaoka volcanic ash layers, in the ascending order. 2. Mineralogical analyses and paleomagnetic measurements of the volcanic ash layers found in this area are shown in Table 1, 2 and Fig. 5-a, b. It is remarkable that the normal polarity interval, which is correlative to the Olduvai Event, is found in the horizon between Kiryu I anp Minogo volcanic ash layers. 3. Some plant megafossils collected from the lower and middle horizons of this area are the elements of the Metasequoia flora. On the other hand, the elements of flora showing the Quaternary cold climate are found in the upper horizons of the Kobiwako Group in this area. The floral change can be found in the horizons near Maruoshinden volcanic ash layer. 4. The Kobiwako Group in this area generally abuts to the basements and dips to the north or northwest gently. There are found no remarkable geologic structures except few places; in the east of Ono and near Mikumo are found flexures and faults. 5. Gokenjaya volcanic ash layer is lithologically similar to Gamodo volcanic ash layer found in Minakuchi Hills. Horizons directing to the Quaternary cold climate can coincide with the uppermost horizons of the Minakuchi Hills. Based on these and other studies, the lower half of the Kobiwako Group distributed in this area can be correlated to the upper half of the Group in Minakuchi Hills.

収録刊行物

  • 地球科学

    地球科学 35 (1), 26-40, 1981

    地学団体研究会

被引用文献 (13)*注記

もっと見る

詳細情報 詳細情報について

問題の指摘

ページトップへ