ID | 65479 |
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Sort Key | 3
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タイトル(別表記) | Geology of the Paleogene to Neogene successions and gentle upwarping of the Kibi Plateau Surface, surrounding area of Kibichuou Town, Okayama Prefecture, Southwest Japan
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フルテキストURL | |
著者 |
田中 元
西部技術コンサルタント株式会社
鈴木 茂之
岡山大学理学部地球科学科
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抄録 | The Paleogene to Neogene successions which are composed of the Paleogene Kayo Formation, the late Oligocene to earliest Miocene Yagane Formation and the middle Miocene Ukan Formation are sporadically distributed in the Kibi Plateau region, surrounding area of Kibichuou Town, Okayama Prefecture, Southwest Japan. The gravel of the Kayo Formation occupied paleo-valley of Pre-Paleogene basement. The Yagane and Ukan formations unconformably overlay Pre-Paleogene rocks and occupy the gentle valley on the Kibi Surface as valley fill deposits.
The fluvial of the Kayo Formation is mainly composed of conglomerate with minor amount of sandstone and mudstone. The fluvial Yagane Formation is mainly composed of conglomerate and associated with sandstone, mudstone and coal beds. The marine Ukan Formation is subdivided into 3 members, the Yamagata Muddy sandstone Member (YMM), the Shimoyokomi Sandstone Member (SSM) and the Tsuneyama Mudstone Member (TMM) in ascending order. The YMM is characterized by the bio-disturbed very poorly sorted muddy sandstone with frequent burrows, which indicate tidal flat deposits. The SSM is mainly composed of parallel bedded well-sorted sandstone with occasional burrows, which suggest near shore deposits. The TMM is composed of homogeneous clay rich mudstone, which implies off shore deposits. The boundary between the SSM and TMM (the contact of the sandstone and mudstone) is distinctive and correlative throughout the study area. The boundary is considered to be formed under similar water depth. The variations of the boundary height indicate a later ground movement. From the north to the south in about 25km distance, the height of the boundary changes 260m (in Ukan), 300m (in Takeshou), 360m (in Kibikogentoshi) and 260m (in Nichiouji). It indicates that a very gentle upwarping of the Kibi Plateau Surface was formed after the deposition of the Miocene. |
キーワード | Kibi Plateau Surface
Upwarping
Miocene
Ukan Formation
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出版物タイトル |
Okayama University Earth Science Report
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発行日 | 2023-03-31
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巻 | 29巻
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号 | 1号
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出版者 | 岡山大学理学部地球科学科
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出版者(別表記) | Department of Earth Sciences, Faculty of Science, Okayama University
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開始ページ | 1
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終了ページ | 27
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ISSN | 1340-7414
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NCID | AN10506284
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資料タイプ |
紀要論文
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OAI-PMH Set |
岡山大学
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言語 |
日本語
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著作権者 | © 2023 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
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論文のバージョン | publisher
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Eprints Journal Name | esr
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