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マグマ上昇過程における発泡と結晶作用のタイミング : 有珠山2000年噴火,マグマ水蒸気爆発の例
https://doi.org/10.15083/0000032621
https://doi.org/10.15083/0000032621fcb221a2-adc3-48ac-99a1-980053bcbfa8
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
ji0762008.pdf (2.5 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2008-05-30 | |||||
| タイトル | ||||||
| タイトル | マグマ上昇過程における発泡と結晶作用のタイミング : 有珠山2000年噴火,マグマ水蒸気爆発の例 | |||||
| 言語 | ja | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | magma ascent | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | phreatomagmatic eruption | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | vesiculation | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | microlite | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | volatile exsolution | |||||
| 資源タイプ | ||||||
| 資源 | http://purl.org/coar/resource_type/c_6501 | |||||
| タイプ | departmental bulletin paper | |||||
| ID登録 | ||||||
| ID登録 | 10.15083/0000032621 | |||||
| ID登録タイプ | JaLC | |||||
| その他のタイトル | ||||||
| その他のタイトル | Timing of vesiculation and crystallization during magma ascent : Example of the phreatomagmatic phase in Usu 2000 eruption | |||||
| 著者 |
鈴木, 由希
× 鈴木, 由希× 中田, 節也 |
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| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 126317 | |||||
| 姓名 | Suzuki, Yuki | |||||
| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 126318 | |||||
| 姓名 | Nakada, Setsuya | |||||
| 著者所属 | ||||||
| 著者所属 | 東京大学地震研究所 | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | A phreatomagmatic phase at Usu volcano, Hokkaido, on 31 March, 2000, issued essential dacite pumice and micropumice in ash. The magma ascent process of the eruption was investigated using these pumiceous samples. Compositions of individual phenocryst (magnetite, plagioclase, orthopyroxene) rims and groundmass (microlite plus glass, 75.0 wt.% SiO2) are uniform among the pumiceous fragments, showing chemically homogeneous melt before eruption. The water content in the melt before eruption is estimated to be around 5 wt.%, based on both indirectly estimated water content of glass inclusions in phenocrysts and the phase relationship. This means that the magma had been saturated with water at around 2kbar. The essential fragments vary in vesicularity (15-80 vol.%). The H2O content in groundmass glass decreases with increasing vesicularity. These facts suggest that variable vesicularity resulted from different quenching depths of the dacite magma in the aquifer, heterogeneity of H2O exsolution in dacite magma, or different response of H2O exsolution due to a changing ascent rate. The water content of groundmass glass corresponds to the solubility at lower than 0.3 kbar. However, the latter pressure is higher than the pressure under which the most plausible aquifer lies. Fragmentation of pumices into small pieces may have been caused by water quenching, however, highly vesiculated pumice of larger dimensions may have been formed without any interaction with water. Microlites in groundmass have a higher number density than phenocrysts, indicating that the former nucleated under high degree of supercooling during eruption. Chemical compositions of individual microlite species are homogeneous among essential fragments. This indicates that microlites had been crystallized under a similar physical condition and independently from quenching in the aquifer. Low water content in groundmass glass suggests the possibility of enough decompression-induced undercooling for the crystallization until quenching. However, constant microlite crystallinity among essential materials with various vesicularity can be explained by the completion of crystallization before the final decompression. | |||||
| 書誌情報 |
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo 巻 76, 号 2, p. 253-268, 発行日 2001-09-25 |
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| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 00408972 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00162258 | |||||
| フォーマット | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | application/pdf | |||||
| 日本十進分類法 | ||||||
| 主題Scheme | NDC | |||||
| 主題 | 453 | |||||
| 出版者 | ||||||
| 出版者 | 東京大学地震研究所 | |||||
| 出版者別名 | ||||||
| Earthquake Research Institute, University of Tokyo | ||||||
