2019 Fiscal Year Final Research Report
Subduction mechanism of nitrogen to deep Earth by organic component in sediments
| Project/Area Number |
16K17839
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geochemistry/Cosmochemistry
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Keywords | 沈み込み帯 / 窒素 / 芳香族化合物 / 高温高圧実験 / ダイヤモンドアンビル / ピストンシリンダー / GC/MS |
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| Outline of Final Research Achievements |
In this study, subduction mechanism of nitrogen into the Earth interior by organic component in sediment was investigated. Pyrolysis of aromatic compounds, which is a major component of organic component in sediment was investigated using high-pressure high-temperature experiments. GC/MS analysis of the recovered samples revealed that position of nitrogen atoms in the aromatic rings strongly cause to mechanism of the decomposition and oligomerization/polymerization of aromatic rings. The N-N covalent bond in the heterocyclic aromatic compound is easily dissociated and the aromatic ring consisting of both nitrogen and carbon opens at lower temperatures than that of aromatic hydrocarbons. Nitrogen atoms might be released from organic sediments around 70-80 km in cold subducting slab.
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| Free Research Field |
高圧地球化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では全地球規模での窒素の循環を明らかにするため、地上から地球の内部にどのような形で窒素が運搬されるかを解明することを目的として沈み込み帯の温度圧力条件を再現した実験を行った。窒素を運搬するリザ―バーとして堆積物中の有機物に着目し芳香族化合物をモデル物質とした実験を進めた、窒素が芳香環に単独で取り込まれている場合には、温度、圧力の上昇に伴って高分子化が起きるが窒素の含有率はほとんど変わらなかったことから
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