2013 Fiscal Year Final Research Report
Experimental research on rheology and seismic wave velocity properties of partially molten lower crustal rocks
| Project/Area Number |
22740328
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Geology
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| Research Institution | Tohoku University |
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Principal Investigator |
MUTO Jun 東北大学, 理学(系)研究科(研究院), 助教 (40545787)
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| Project Period (FY) |
2010-04-01 – 2014-03-31
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| Keywords | 下部地殻 / レオロジー / 部分溶融 / 岩石変形 / 地震波速度 |
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| Research Abstract |
In order to estimate the effect of melt and water on the rheological behavior of the lower crust, high pressure and temperature deformation experiments were conducted using Griggs type solid medium apparatus. Increases in the melt content decreases flow strengths under the presence of water. The flow stress decreases with increasing the water content added to the sample and decreasing strain rate. This indicates that the flow strength of anorthite aggregates is determined by the amount of water contents introduced into the aggregate. The water content required to cause weakening was consistent with the lower bound of water contents in the lower crust estimated by geophysical observations. The water contents left in the weakened samples measured after deformation experiments are consistent with naturally deformed feldspars. This indicates that the amount of water in the lower crust controls the rheological behavior of lower crustal rocks.
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