| Project/Area Number |
18H01297
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | Tohoku University |
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Principal Investigator |
Muto Jun 東北大学, 理学研究科, 准教授 (40545787)
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| Co-Investigator(Kenkyū-buntansha) |
奥平 敬元 大阪市立大学, 大学院理学研究科, 教授 (20295679)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000)
Fiscal Year 2020: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2019: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2018: ¥13,000,000 (Direct Cost: ¥10,000,000、Indirect Cost: ¥3,000,000)
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| Keywords | 上部地殻 / 脆性塑性遷移 / レオロジー / 地殻応力 / 脆性－塑性 / 断層剪断帯 / 歪の局所化 / 花崗岩 / 脆性－塑性遷移 / 剪断帯 |
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| Outline of Final Research Achievements |
The strength of the continental crust has been investigated using the rheology of quartz, a principal constituent of the upper crust, and begins to flow at the lowest temperature. However, the granitic rocks consisting of the upper crust are composed of polymineralic, including feldspar, which is stronger than quartz, and biotite, which is significantly weaker than quartz. In this study, we created a rock deformation apparatus with solid-confining media targetting the highest pressure in Japan and conducted deformation experiments of the polymineralic rock samples, including quartz-feldspar-mica, to investigate the strength and deformation mechanism near the brittle-plastic transition. From these experiments, we succeeded in clarifying the deformation behavior of rocks near brittle-ductile transitions, comparable to the previously proposed rheological models of the upper crust based on quartz rheology.
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| Academic Significance and Societal Importance of the Research Achievements |
これまで地殻応力や地震発生分布などを議論するレオロジー断面では、上部地殻の強度を花崗岩中で最も低温で流動変形を始める石英の変形特性で代表してきた。一方で、多相系岩石においては、その強度が歪や組成に応じて変化することが知られているが、歪の効果を含んだ多相系岩石のレオロジーモデルは未だ提案されていない。本研究において、多相系岩石の強度と各鉱物の微細組織と変形機構を歪の関数として定量的に評価したことで、より実際の構成岩石の変形特性に基づく上部地殻の強度モデルの構築が可能になり、物質科学に基づく地震サイクルモデルの構築などにも貢献する。
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