| 项目编号: | 1654687
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| 项目名称: | CAREER: Deformation and Anisotropy Development in the Lower-most Mantle |
| 作者: | Lowell Miyagi
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| 承担单位: | University of Utah
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| 批准年: | 2017
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| 开始日期: | 2017-07-01
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| 结束日期: | 2022-06-30
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| 资助金额: | 310779
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| 资助来源: | US-NSF
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| 项目类别: | Continuing 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: | mantle convection
; mantle flow
; anisotropy
; project
; deformation
; d
; mantle
; seismic anisotropy
; mantle assemblage
; mantle mineral phase
; poly-phase deformation
; mantle phase
; core mantle boundary
; temperature deformation experiment
; texture development
; ductile deformation
; deformation structure
; mineral
|
| 英文摘要: | Mantle convection is the internal engine which drives dynamic processes such as earthquakes and volcanism. Since there is no direct way to image mantle flow, our knowledge about this process is limited. This project will improve our ability to link seismic observations to deformation structure and flow geometry in the deep Earth. In particular it will provide experimental data on the strength on rocks and minerals at the base of the mantle and will determine the microscopic mechanisms that lead to flow alignment of minerals in the deep earth. Understanding the dynamic processes at the base of the mantle will provide new insight into the mechanics and geometry of mantle convection. High pressure and temperature deformation experiments performed during this project will also advance our understanding of the mechanical behavior of composite materials subjected to extreme pressure and temperature conditions. In addition to basic science advances the outreach component of this project will improve undergraduate recruitment into geosciences through early exposure in secondary schools. It will directly benefit the quality of secondary school education in Utah by providing mentoring and authentic research experience to secondary school teachers through the Masters of Science for Secondary School Teachers (MSSST) Program at the University of Utah. In addition, through collaboration with MSSST teachers, the PI will develop geophysics teaching modules to be incorporated into secondary school earth science, physics, and chemistry courses. This project will also provide support and training for a graduate student and a postdoctoral researcher.
The D" region, which lies just above the core mantle boundary (~2700-2900 km), plays a critical role in mantle convection. Understanding the dynamic processes occurring in the D" will advance our understanding of mantle convection. Seismic anisotropy is observed in much of the D" and is widely attributed to crystal preferred orientation (texture) of minerals that results from ductile deformation during mantle convection. If the relationship between deformation, texture, and anisotropy are understood, anisotropy can be used to map mantle flow. Most interpretations of D" anisotropy in terms of mantle flow are based on texture studies related only to deformation and in the context of single phase experiments. However, high pressure diamond anvil cell experiments on lower mantle phases have documented a range textures that develop due to phase transformations. Additionally the few texture measurements that exist for deformation of multi-phase lower mantle assemblages (rocks) suggest complex interactions between the phases. This project will use the diamond anvil cell and synchrotron radial diffraction to study orientation relationships and texture inheritance during bridgmanite and post-perovskite phase transitions and will investigate the effects of poly-phase deformation on texture development in lower mantle mineral phases. By understanding these processes, this proposal will enhance our ability to interpret seismic anisotropy in terms of phase transformations and mantle flow. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/89784
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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: | |
Lowell Miyagi. CAREER: Deformation and Anisotropy Development in the Lower-most Mantle. 2017-01-01.
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