埼玉県日高市に分布する矢おろし凝灰岩層および飯能れき層の堆積環境

DOI Web Site 被引用文献4件 参考文献17件

書誌事項

タイトル別名
  • Sedimentary Environments of Yaoroshi Tuff and Hanno Gravel Distributed in Hidaka City, Saitama Prefecture.
  • サイタマケン ヒダカシ ニ ブンプスル ヤオロシ ギョウカイガンソウ オヨビ

この論文をさがす

説明

Plio-Pleistocene fluvial sediments are distributed in the hills along the western margin of the Kanto Plain. In this paper, the author reports its sedimentary environments at Hidaka City, Saitama Prefecture, namely, those of Yaoroshi tuff, Hanno gravel and their correlatives.<BR>The basement in this area (Chichibu Paleozoic and Mesozoic formations and Takaoka formation) is divided into three zones structurally by Koma-Hongo and Komagawa fault systems. And terrace deformation dipping toward the Kanto Plain is recognized on its surface.<BR>Yaoroshi tuff is in fault or unconformity contact with the basement in part of Koma-Hongo fault system. The vertical displacement of each fault system is over 50 m. Yaoroshi tuff is not distributed in west of Koma-Hongo fault system.<BR>Hanno gravel, conformably overlying Yaoroshi tuff, is in fault or unconformity contact with the basement. Hanno gravel and its correlatives were formed by old long rivers, of and the valley bottoms were at least 140 m above sea level in Koma River system area and at least 150 m above sea level in Shukuya River system area.<BR>Boulders of granite and diorite characterizing Hanno gravel in the south of Tenran-zan (Mt. Tenran) are not found in the investigated area. This fact suggests that the area was in different conditions of sedimentation from the southern area. The ridge directions of Koma Hills and Moroyama Hills had already settled before dissection proceeded.<BR>The gravel from Moroyama Hills and the adjacent areas is divided into the lower and the upper layers. The former is correlated with Yaoroshi tuff, while the latter with Hanno gravel.<BR>When Yaoroshi tuff deposited, forested stable land had extended widely. And short rivers flowing out from near mountains sometimes flooded and destroyed forests. After Yaoroshi tuff was formed, long rivers transported boulders with sands in large quantities from distant western mountains. These old long rivers kept their main courses to the present as Koma River system and Shukuya River system, and they mixed gravels by gathering currents and forming talus deposits.

収録刊行物

  • 地学雑誌

    地学雑誌 104 (2), 267-283, 1995

    公益社団法人 東京地学協会

被引用文献 (4)*注記

もっと見る

参考文献 (17)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ