Geology and integrated chronostratigraphy of the Miocene marine sequence in the Tomioka area, Gunma Prefecture, central Japan

DOI Web Site Web Site 15 Citations 51 References
  • Takahashi Masaki
    Integrated Bio- and Chronostratigraphy Group, Institute of Geoscience, Geological Survey of Japan/AIST
  • Hayashi Hiroki
    Solid Earth Research Group, National Research Institute for Earth Science and Disaster Prevention

Bibliographic Information

Other Title
  • 群馬県富岡地域に分布する中新統の地質と複合年代層序
  • グンマケン トミオカ チイキ ニ ブンプ スル チュウ シントウ ノ チシツ ト フクゴウ ネンダイソウ ジョ

Search this article

Abstract

Previously reported planktonic microfossils and radiometric ages of volcaniclastic layers of the Miocene marine sequence in the Tomioka area are reviewed. Based on the biostratigraphic and radiometric ages, sediment accumulation history and geologic structure, more than 3, 600m-thick marine sequence of the Tomioka area is divided into lower Tomioka Group (partly modified) and upper Annaka Group (newly difined). The Annaka Group covers the Tomioka Group, unconformably (Niwaya Unconformity). High sedimentation rate of 200 cm/1, 000yr. characterizes the Tomioka Group. In contrast, sandstone to sandy siltstone succession of the upper half of the sequence (Annaka Group) shows relatively slow sedimentation rate of less than 40 cm/1, 000yr. High sedimentation rate of the Itahana Formation is due to the development of submarine delta related to regression.

Journal

Citations (15)*help

See more

References(51)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top