JaLCDOI 10.18926/ESR/13885
Title Alternative Miocene Ukan Formation, Ukan Area, Okayama Prefecture, Southwest Japan
FullText URL ESR_8_1_1.pdf
Author Fujiwara, Takao| Taguchi, Eiji| Suzuki, shigeyuki|
Abstract In this paper, we deal with the Miocene Ukan Formation, sporadically distributed in Ukan-cho, Okayama prefecture, from a viewpoint of analysis of lithology and molluscan assemblages. The Ukan Formation is lithostratigraphically divided into the Suzuoka Conglomerate, Yamagata Muddy Sandstone, Shimoyokomi Sandstone and Conglomerate, Azechi Sandstone and Conglomerate, Tsuneyama Siltstone Members in ascending order. The following 6 molluscan assemblages are recognized. The lower four members and the last member is correlative to the Lower Sandstone and Upper Shale Formation of the Bihoku Group, respectively judging from lithology and fauna. The temporal chages of the above mentioned molluscan assemblages represents that gradual deeping of sea during the depositional period from the Suzuoka Conglomerate and Yamagata Muddy Sandstone Members to the Azechi Sandstone and Conglomerate Member via the Shimoyokomi Sandstone and Conglomerate Member, and abrupt deeping of sea seems to have happened between the Azechi Sandstone and Conglomerate Member and the Tsuneyame Siltstone Member.
Keywords Lithology Molluscan assemblage Paleoenvironmental change Ukan Miocene
Publication Title Okayama University Earth Science Report
Published Date 2001-09-20
Volume volume8
Issue issue1
Start Page 1
End Page 12
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310604