ID | 66844 |
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Sort Key | 3
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タイトル(別表記) | Petrological characteristics of the stone chamber of Tobiotsuka Kofun, Okayama Prefecture
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フルテキストURL | |
著者 |
金子 峻大
岡山大学大学院自然科学研究科
清家 章
岡山大学学術研究院社会文化科学学域
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抄録 | Tobiotsuka Kofun, a tumulus built on the Misu Hills in the Kofun period, has a horizontal stone chamber made of huge stone blocks with a width up to 2 meters or more. To specify the source of the stone blocks, we carried out the measurement of magnetic susceptibility, petrographic observation, and chemical analysis of minerals. The stones are amphibole-biotite granite with phenocrystic large grains of K-feldspar. The back-wall stone of the chamber has higher magnetic susceptibility than ceiling and side-wall stones, which probably results from a higher amount of magnetite formed by the alteration of biotite in the back-wall stone. Furthermore, the back-wall stone is different from ceiling stone in that it has lower XMg [Mg/(Mg + Fe) mole ratio], lower Al, Ti, and Na + K contents and higher Si contents of amphibole, higher XMg of biotite, and shows a tendency to have higher Na (albite component) contents at rims of plagioclase crystals and lower Ti contents of zircon. These characteristics of the back-wall stone are similar to those of granite exposed in the Koshinzan area about 2 km northeast of Tobiotsuka Kofun, whereas the ceiling and side-wall stones are similar to granite outcrops in the vicinity of Tobiotsuka Kofun, e.g., in the Midoriyama area. It is concluded that the quarry for the back-wall was located at a different place from that for the ceiling and side-wall stones.
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キーワード | Tobiotsuka Kofun
stone chamber
granite
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出版物タイトル |
Okayama University Earth Science Report
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発行日 | 2024-03-31
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巻 | 30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 | 12
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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 | © 2024 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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助成機関名 |
文部科学省
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助成番号 | 20H05634
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