Dynamism of fluid pressure in subduction zones revealed by tracer-diffusion experiments on reaction zones
| Project/Area Number |
18K13628
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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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 |
Uno Masaoki 東北大学, 環境科学研究科, 助教 (50748150)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 沈み込み帯 / 地殻流体 / 岩石ー流体反応 / 流体圧 / 浸透率 / 反応輸送モデル / 地殻浸透率 / 地殻流体圧 / 岩石ー水反応 / 変成作用 / 中部下部地殻 / 流体圧分布 / 流体活動タイムスケール / 反応輸送モデリング / 亀裂閉塞タイムスケール / 流体圧変動 / 拡散 / 透水係数 |
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| Outline of Final Research Achievements |
To understand the fluid activities in the deep crust, we have developed a novel method that reveals fluid pressure and permeability of the crustal material from metamorphic reaction zones. Application of reactive-transport model to crustal fluid-rock reaction zone was verified by hydrothermal experiments replacing marble by apatite. Analyses of natural metamorphic reaction zone revealed that the time-scales of fluid activities in the fractures ranged from hours to years. Permeability (in log10 [m2] unit) significantly change from -22~-20 in intact crust to -15~-10 in fractures. It is suggested that the widely accepted crustal permeability (-18) is a ~Myr-scale temporal average, and crustal permeability fluctuates for more than 5 orders in the time-scales of hours to years.
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| Academic Significance and Societal Importance of the Research Achievements |
地震波観測などで間接的に推測されていた，地殻流体圧と浸透率の変動を，岩石ー流体反応帯から定量的に示した．従来，示されていた地殻浸透率の値は，百万年スケールの時空間平均であり，年ー時間スケールでは，ダイナミックに変動していることを明らかにした．
本研究では，地震波から観測される地殻流体活動と，地質学的に観察される岩石ー流体反応帯を，具体的な時間スケールや流体圧，浸透率をとおして定量的な比較を可能とした．
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Report
(3 results)
Research Products
(77 results)
