CAREER: Deformation and Anisotropy Development in the Lower-most Mantle

GSTDTAP

项目编号	1654687
	CAREER: Deformation and Anisotropy Development in the Lower-most Mantle
	Lowell Miyagi
主持机构	University of Utah
项目开始年	2017
	2017-07-01
项目结束日期	2022-06-30
资助机构	US-NSF
项目类别	Continuing grant
项目经费	310779(USD)
国家	美国
语种	英语
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.
来源学科分类	Geosciences - Earth Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71239
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Lowell Miyagi.CAREER: Deformation and Anisotropy Development in the Lower-most Mantle.2017.