2018 Fiscal Year Final Research Report
Study on long-term geomagnetic field variations during the last 10 million years
| Project/Area Number |
16H02233
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
堀内 一穂 弘前大学, 理工学研究科, 助教 (00344614)
山本 裕二 高知大学, 教育研究部総合科学系複合領域科学部門, 教授 (00452699)
中村 教博 東北大学, 高度教養教育・学生支援機構, 教授 (80302248)
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| Research Collaborator |
Kumagai Yuho
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 古地磁気 / 古地磁気強度 / 伏角異常 / IODP / ベリリウム同位体 |
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| Outline of Final Research Achievements |
A continuous geomagnetic paleointensity record during the last 8 million years was obtained uising marine sediment cores. Influence of sediment lithology variations on relative paleointensity estimations was evaluated and corrected. No discernible relation was found among mean paleointensity, polarity length, and polarity for this time interval. From inclination anomaly averaged over each polarity chron, the presence of a small polarity bias was confirmed for the last 5 million years. A shift of the sign of the inclination anomaly may have occurred before about 6 million years.
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| Free Research Field |
古地磁気学
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| Academic Significance and Societal Importance of the Research Achievements |
過去約800万年間の古地磁気強度変動及び伏角異常の連続的な記録を得たのは世界で初めてであり、学術的意義が大きい。また、現在当該分野で大きな問題となっている、相対古地磁気強度推定への堆積物岩相変化の影響について、それを見積もり補正する道をひらいたことで、今後、相対古地磁気強度記録の統計解析に基づいた、古地磁気強度と地球軌道要素の関係、逆転間隔との関係などの理解が進むと期待される。
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