| 项目编号: | 1522012
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| 项目名称: | Collaborative Research: The Asthenosphere and Mantle Dynamics |
| 作者: | Adrian Lenardic
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| 承担单位: | William Marsh Rice University
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| 批准年: | 2016
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| 开始日期: | 2016-02-15
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| 结束日期: | 2017-06-30
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| 资助金额: | 88327
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | plate tectonic
; earth
; asthenosphere
; bulk mantle
; dynamics
; low viscosity asthenosphere
; motion
; low-viscosity asthenosphere
; upper mantle
; mantle dynamics
; asthenosphere structure
; numerical mantle convection experiment
; plate motion
; mantle convection
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| 英文摘要: | The majority of changes that occur on our planet can be tracked back to one of two energy sources: 1) Energy from the sun and 2) Energy from the Earth's interior. How interior energy shapes the Earth's surface links directly to understanding the dynamics of plate tectonics. Plate tectonics stands as one of the three major scientific revolutions of the 20th century, along with quantum mechanics and relativity. As a theory it remains a kinematic one in that it describes the motion of plates at the Earth's surface but does not connect the motions directly to the forces that drive the motion. Extending plate tectonics theory from a kinematic one to a dynamic one has been a something of a grand challenge in the geological and geophysical communities. From the inception of plate tectonics as a kinematic theory, it has been suspected that the dynamics of plate tectonics is connected to the existence of a low viscosity zone below plates - the asthenosphere. Mapping, quantifying, and seeking to bring conceptual understanding to several of the factors that tie into this long suspected connection is the theme of this work. More specifically, over the next one year cycle, the team will: A) Test the hypothesis that changes in asthenosphere structure can drive rapid changes in plate motion of the type recently identified to have occurred on the Earth 50-100 Million years ago and B) Explore the interaction between plate tectonics and the cycling of volatiles between surface reservoirs and the Earth's deep interior (e.g., deep water cycling can effect the nature of the asthenosphere through its role on rock melting).
The investigators will explore the effects of a low viscosity asthenosphere on mantle dynamics. Numerical mantle convection experiments will be used to map the combined effects of a low-viscosity asthenosphere and plate boundary failure on maintaining a plate-tectonic mode of mantle convection. A specific goal will be to identify conditions that allow for rapid changes in plate motions, as have recently been inferred for the Earth's Cretaceous. Numerical work will be augmented with theoretical scaling analysis. The analysis will provide insight into energetic balances between the resistance to plate motion associated with dissipation at plate margins, within the asthenosphere, and in the bulk mantle. This will allow the PIs to link dynamic modeling to instantaneous flow studies that isolate the balance of dissipation between plate processes and the bulk mantle. That link will bring added observational constraints to bear on their results and predictions. The analysis will also be extended to model deep volatile cycling (water and carbon) within the Earth and volatile exchange from the surface to the interior of our planet over geologic time. The key feedback this introduces, relative to the role of the asthenosphere on maintaining plate tectonics, comes from the ability of volatiles to effect melting in the upper mantle, which can significantly alter the structure of the asthenosphere. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92861
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Adrian Lenardic. Collaborative Research: The Asthenosphere and Mantle Dynamics. 2016-01-01.
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