Pile-nappe structure of the Ryokami-yama chert unit in the Chichibu composite terrane of the Kanto Mountains, central Japan

• Yoshida Kazuhiro

• Matsuoka Atsushi

Bibliographic Information

Other Title

• 関東山地秩父累帯両神山チャートユニットのパイルナップ構造
• カントウ サンチ チチブ ルイタイ リョウカミヤマ チャート ユニット ノ パイルナップ コウゾウ

Abstract

Detailed mapping of the Ryokami area in the Kanto Mountains, Saitama Prefecture, revealed that the Ryokami-yama chert unit is divided into three subunits (Subunit 1, 2 and 3 from bottom to top). Each subunit is composed mainly of chert beds and overlying clastic rocks. This unit is characterized by a pile-nappe structure of chert-elastics sequences. Middle Jurassic radiolarian fossils were found from the uppermost part of chert beds of Subunit 1 and Subunit 2 as well as from the siliceous mudstone of Subunit 1 and Subunit 2. The transitional horizon from chert to clastics in these subunits is of Bajocian to early Bathonian age. Judging from lithological features and geological age, the Kashiwagi Formation and the Hashidate Group in the Northern Chichibu terrane should not be the origin of the Ryokami-yama chert unit. This disagrees with the previous interpretation. The Ryokami-yama chert unit is better compared to the Unazawa Formation in the Southern Chichibu terrane or to the Kamiyoshida Formation in the Northern Chichibu terrane.

Journal

• The Journal of the Geological Society of Japan

  The Journal of the Geological Society of Japan 109 (6), 324-335, 2003

  The Geological Society of Japan

Keywords

• Saitama Prefecture

Details

• CRID: 1390282681213615744
• NII Article ID: 110003009802
• NII Book ID: AN00141768
• DOI: 10.5575/geosoc.109.324
• ISSN: 13499963
• ISSN: 00167630
• HANDLE: 10191/6269
• NDL BIB ID: 6629391
• Web Site: https://niigata-u.repo.nii.ac.jp/records/3211
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I6629391
• Text Lang: ja
• Data Source:
  • JaLC
  • IRDB
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed