2002 Fiscal Year Final Research Report Summary
Large sulfur supply from arc volcanoes : Sulfur concentrations of melt in clusions in olivine phenocryst
| Project/Area Number |
13640456
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Shinshu University |
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Principal Investigator |
YAHAGUCHI Yoshiaki Shinshu University, faculty of Science, prof., 理学部, 教授 (50144689)
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| Co-Investigator(Kenkyū-buntansha) |
MAKINO Kuniaki Shinshu University, faculty of Science, ass. prof., 理学部, 助教授 (30242712)
HARAYAMA Satoru Shinshu University, faculty of Science, prof., 理学部, 教授 (60293536)
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| Project Period (FY) |
2001 – 2002
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| Keywords | sulfur / melt inclusion / olivine / mafic gagma / island arc / magma mixing |
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| Research Abstract |
Oliven phenocrysts in eruptive products were collected from active volcanoes in the northeast Honshu arc from southern Hokkaido through northeast Honshu to central (Kanto-tyubu district) Japan. Along the volcanic fronts, there are many sulfur fumaroles, and native sulfur ore had been mined from ancient time. Petrographic and mineralogical observations of these eruptive products reveal that olivine phenocrysts were derived from mafic magma, while ortho- and clinopyroxenes, plagioclases and Fe-Ti oxides consisted of felsic crystal mush of the felsic reservoirs in the mixed magma systems.
Olivine generally trapped sulfur-rich mafic silicate melt inclusions with basaltic-basaltic andesite compositions, and include immiscible sufide phases. Measured peak shift of the S-K_<alpha> for the melt inclusions determined sulfur species and estimate the oxidation state of magma. The subduction-related magmas are expected to supply large amounts of sulfur to the volcanic magma system under a hydrous, oxidized conditions, and largr amounts of sulfur were released during eruptions.
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