沈み込み帯火山の長期進化過程 : 千島弧南部, 利尻火山の地質学・岩石学・地球化学

• Material Type: 博士論文
• Title: 沈み込み帯火山の長期進化過程 : 千島弧南部, 利尻火山の地質学・岩石学・地球化学
• Author/Editor: 谷内, 元
• Author Heading: 谷内, 元
• Publication, Distribution, etc.: Hokkaido University
• Publication Date: 2021-03-25
• Publication Date (W3CDTF): 2021-03-25
• Alternative Title: Long-term evolution of a subduction zone volcano : Geology, petrology, and geochemistry of Rishiri Volcano, southern Kuril Arc
• Contributor: 栗谷, 豪; 中川, 光弘; 永井, 隆哉; 吉村, 俊平
• Degree Grantor: 北海道大学
• Date Granted: 2021-03-25
• Date Granted (W3CDTF): 2021-03-25
• Dissertation Number: 甲第14364号
• Degree Type: 博士(理学)
• Conferring No. (Dissertation): 甲第14364号
• Text Language Code: eng
• NDC: 400
• Target Audience: 一般
• Note (General): (主査) 准教授 栗谷 豪, 教授 中川 光弘, 教授 永井 隆哉, 助教 吉村 俊平; 理学院（自然史科学専攻）
• DOI: 10.14943/doctoral.k14364; https://doi.org/10.14943/doctoral.k14364
• Persistent ID (NDL): info:ndljp/pid/11864290; https://dl.ndl.go.jp/pid/11864290
• Collection: 障害者向け資料
• Collection (Materials For Handicapped People:1): テキストデータ
• Collection (particular): 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文; https://dl.ndl.go.jp/collections/A00014
• Acquisition Basis: 博士論文（自動収集）
• Date Accepted (W3CDTF): 2021-11-08T14:10:24+09:00
• Format (IMT): PDF
• Access Restrictions: 国立国会図書館内限定公開
• Service for the Digitized Contents Transmission Service: 図書館・個人送信対象外
• Availability of remote photoduplication service: 可
• Periodical Title (URI): https://doi.org/10.14943/doctoral.k14364; http://hdl.handle.net/2115/82852
• Is Referenced By (URI): http://hdl.handle.net/2115/81952
• Data Provider (Database): 国立国会図書館 : 国立国会図書館デジタルコレクション; https://dl.ndl.go.jp

• Summary, etc.: Subduction zone is one of the most active areas of magmatism on the Earth, and many geophysical and petrological studies have been carried out. However, the debates on the longterm evolutionary processes and their controlling factors of subduction zone volcanoes have not been put to rest. In this study, I carried out geological, geochronological, petrological, and geochemical studies at the Rishiri Volcano, southern Kuril Arc, to understand the long-term evolution of a subduction zone volcano. In Chapter 2, I obtained new K-Ar, Ar/Ar, and 14C ages to create the time–cumulative volume step diagram and show that the eruption rate was high in the Early- 1 and Middle stages, intermediate in the Early-2 and Late-1 stages, and low in the Late-2 stage. Besides, it was indicated that there was a clear relationship between the eruption rate and the chemical composition of volcanic products. In Chapter 3, I showed that the calc-alkaline andesites that erupted during the Middle stage were essentially formed through the magma mixing between the mantle-derived magma and crust-derived magma. The water content of the primitive end-member magma of the calc-alkaline andesite was obtained to be ~5 wt.%, which is predominantly higher than other primitive magmas that produced basalts and tholeiitic andesites to dacites. It was suggested that the water content of primary magma control the differentiation process in the crust. In Chapter 4, I carried out a geochemical study of the adakitic dacites in the Middle stage to clarify the nature and behavior of slab-derived fluids. The results showed that the adakitic dacites were not produced by partial melting of crustal rocks and fractional differentiation from mantle-derived magma, but rather by the involvement of slab-derived materials. It was indicated that the slab-derived supercritical liquid separated into aqueous fluid and hydrous melt and the former erupted as dacitic magma. In Chapter 5, it was clarified that the elemental partitioning induced by the separation of slab-derived supercritical liquid into aqueous fluid and hydrous melt would play an important role in causing the Na/K variation of primary basaltic magma. In Chapter 6, I summarized the results in Chapters 2 to 5 and discuss the controlling factors in the long-term evolution of the Rishiri Volcano. This study finally proposed that whether or not the slab-derived supercritical liquid separated into aqueous fluid and hydrous melt would determine the chemical composition of primary magma, differentiation processes in the crust, and the eruption rate at the surface and play an important role in the long-term evolution of subduction zone volcanoes.
• DOI: 10.14943/doctoral.k14364; https://doi.org/10.14943/doctoral.k14364
• Format (IMT): application/pdf
• Source: Hajime_Taniuchi.pdf （fulltext）; https://eprints.lib.hokudai.ac.jp/repo/huscap/all/82852/Hajime_Taniuchi.pdf
• Access Restrictions: インターネット公開
• Is Referenced By (URI): HDL; https://hdl.handle.net/2115/81952
• Data Provider (Database): 国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）; https://irdb.nii.ac.jp
• Original Data Provider (Database): 北海道大学 : 北海道大学学術成果コレクション