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Petrography of the Cretaceous Sandstones in the Monobegawa Valley, Shikoku
https://doi.org/10.15027/53053
https://doi.org/10.15027/53053618d081e-7d60-45fb-bf63-caea0faca39c
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
JSHUC_7-2_69.pdf (4.6 MB)
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| Item type | デフォルトアイテムタイプ_（フル）(1) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 公開日 | 2023-03-18 | |||||||||
| タイトル | ||||||||||
| タイトル | Petrography of the Cretaceous Sandstones in the Monobegawa Valley, Shikoku | |||||||||
| 言語 | en | |||||||||
| 作成者 |
MIYAMOTO, Takami
× MIYAMOTO, Takami
× NAKAI, Isao
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| アクセス権 | ||||||||||
| アクセス権 | open access | |||||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||||
| 内容記述 | ||||||||||
| 内容記述 | The Cretaceous System of the Monobegawa valley, Kochi Prefecture, Shikoku, is distributed in a narrow belt within the Paleozoic Chichibu terrain, forming a synclinorium. On the basis of a major cycle of sedimentation, it is divided into the Ryoseki (Kochian), Yunoki (Aritan), Hibihara-Hagino (Mi-yakoan), Nagase (Gyliakian) and Kajisako (Urakawan) Formations in ascending order. The stratigraphy is described in this paper in some detail, and besides the sandstone petrography is carried out to comprehend the mode of the Cretaceous sedimentation definitely. The Cretaceous sandstones mostly show a moderately sorted, normally to positively skewed and meso-to lepto-kurtic type in textural pattern. Besides, most of them are characterized by the feldspathic and lithic wackes and several specimens belong to the feldspathic arenite, based on OKADA's (1971) classification scheme. Judging from the gross lithological features, the Cretaceous sandstones of this basin are referred to a variety of the arenite-wacke associations defined by KRUMBEIN and SLOSS (1963), although resembling the greywackes texturally. The contents in the major and accessory minerals of sandstones and the pebbles of conglomerates suggest that the provenance was composed mainly of older sedimentary, basic volcanic, granitic and metamorphic rocks and they functionated throughout the Cretaceous Period. However, based on the stratigraphical changes of mineralogical composition, which are confirmed by the statistical test, it is concluded that some transition of the provenance took place through the five cycles of sedimentation; the role of the granitic rocks as the source became increased gradually from the Ryoseki through the Yunoki to the Hibihara Formation in the Lower Cretaceous, and then decreased again in the Nagase and Kajisako Formations in the Upper Cretaceous. The mode of this vicissitude seems to be well reflected on the volumetrical change of the feldspar content. From the comparison between the Monobegawa basin and other basins in the Chichibu terrain such as Katsuuragawa and Yatsushiro, it is clarified that there is a close similarity in characteristics of the sandstones and modes of the sedimentation as well as in gross litho- and bio-facies, if excepting minor differences. | |||||||||
| 言語 | en | |||||||||
| 出版者 | ||||||||||
| 出版者 | HIROSHIMA UNIVERSITY | |||||||||
| 言語 | ||||||||||
| 言語 | eng | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||||||
| 資源タイプ | departmental bulletin paper | |||||||||
| 出版タイプ | ||||||||||
| 出版タイプ | VoR | |||||||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||||
| ID登録 | ||||||||||
| ID登録 | 10.15027/53053 | |||||||||
| ID登録タイプ | JaLC | |||||||||
| 収録物識別子 | ||||||||||
| 収録物識別子タイプ | ISSN | |||||||||
| 収録物識別子 | 0075-4374 | |||||||||
| 収録物識別子 | ||||||||||
| 収録物識別子タイプ | NCID | |||||||||
| 収録物識別子 | AA00706718 | |||||||||
| 開始ページ | ||||||||||
| 開始ページ | 69 | |||||||||
| 書誌情報 |
Journal of science of the Hiroshima University. Series C, Geology and mineralogy Journal of science of the Hiroshima University. Series C, Geology and mineralogy 巻 7, 号 2, p. 69-100, 発行日 1974-06-25 |
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| 旧ID | 53053 | |||||||||
