Toward a matle GCM ; the role of the lithosphere in mantle evolution
| Project/Area Number |
10640401
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OGAWA Masaki University of Tokyo at Komabe, Dept. Earth & Space Sciences, associate professor, 大学院・総合文化研究科, 助教授 (30194450)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | mantle convection / magmatism / numerical simulation / plate / mantle evolution / Venus / リソスフェア / 粘弾性 |
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| Research Abstract |
A numerical model is constructed for magmatism and mantle convection, which are the two major agents that transport heat and mass in the mantle of terrestrial planets. Special care is taken (1) to fully include the interaction between magmatism and mantle convection and (2) to realistically reproduce the lithosphere and its plate motion, the major features of mantle convection, in the numerical model. As the first step, the numerical model is constructed for Venus where the lithosphere behaves as a stagnant lid of the mantle and does not show a plate-like motion. The lithosphere is reproduced as the uppermost coldest part of the thermal boundary layer along the surface boundary, where the viscosity is much hither than the viscosity at depth in the mantle because of the strong temperature-dependence of viscosity of mantle materials assumed in the model. The numerically modeled coupled magmatism-mantle convection system episodically induces mantle overturn and the resulting extremely vigorous magmatism. The vigorous magmatism is compared to the volcanic plain formation that took place 500 to 1000 million years ago on Venus. Next, by a systematic search of parameter space for a numerical model of thermal convection with temperature-dependent viscosity, I found a convective regime where the lithosphere develops and slowly moves owing to its ductile deformation. I numerically modeled the coupled magmatism-mantle convection system on this regime, too. Now, I am improving the numerical model of plate-like motion by introducing rupture and the resulting formation of plate boundary in the lithosphere and am obtaining insights into the necessary condition for the occurrence of plate-motion on terrestrial planets. Also, I am including this improved model of plate motion in the model of coupled magmatism-mantle convection system to understand the nature of the coupled magmatism-mantle convection system in the early earth.
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Report
(4 results)
Research Products
(11 results)
