| Project/Area Number |
16K05605
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Economic geology
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| Research Institution | Shizuoka University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
奥村 聡 東北大学, 理学研究科, 准教授 (40532213)
三井 雄太 静岡大学, 理学部, 講師 (80717950)
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| Research Collaborator |
Yasuda Atsushi
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 爆発的噴火 / マイクロライト / マグマ / 減圧結晶作用 / レオロジー / 粘性-脆性遷移 / 苦鉄質 / 斜長石 / テクスチャー / 玄武岩 / 富士火山 / 噴火様式 / 玄武岩質マグマ / 破砕 |
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| Outline of Final Research Achievements |
We performed thermodynamic simulation of degassing-driven crystallization of mafic melts. The results suggest that the behaviors of crystallization are primarily controlled by the temperature of melt and the temperature-dependent change of crystallization behavior is responsible for the variation of eruption style of mafic magmas. In addition, we analyzed run samples of cooling-driven crystallization experiments of a high-Al basaltic melt from Hawaii. The results suggest that kinetic delay of crystallization induces the change of liquid line of descent and overestimation of melt-plagioclase geothermometers against quenched temperatures whereas melt-plagioclase partition coefficient of anorthite component does not depend on substantial cooling rate. Therefore, plagioclase-melt thermmeters can be applied to estimate temperature of natural mafic magmas if kinetic delay is minimum due to the effects of shear flow and/or H2O in melt.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，苦鉄質マグマの噴火ダイナミクスの多様性の原因とされるマイクロライト減圧結晶作用が，マグマの温度によって本質的にコントロールされることを明らかにした．この成果は，苦鉄質マグマの噴火ダイナミクスを理論モデル化するうえで温度が極めて本質的な要素であることを示唆する．また，マグマ温度の本質的重要性を明らかにしたことから，今後，火山噴出物の物質科学的研究を進めるうえでの指針を示したと言える．加えて，火山防災的な観点では，初期に噴出したマグマの温度を調べることで，同じ条件のマグマが噴出した時におこる現象を推測できる可能性を示した．
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