Sound Velocities and Elastiicity of Deep-earth Materials at High Pressures and Temperature

GSTDTAP

项目编号	1620616
	Sound Velocities and Elastiicity of Deep-earth Materials at High Pressures and Temperature
	Jay Bass
主持机构	University of Illinois at Urbana-Champaign
项目开始年	2016
	2016-06-15
项目结束日期	2018-05-31
资助机构	US-NSF
项目类别	Continuing grant
项目经费	198000(USD)
国家	美国
语种	英语
英文摘要	The nature of Earth's interior is highly uncertain, despite its intimate relationship to processes on Earth's surface such as seismicity, volcanism, tectonic mountain-building processes, and re-cycling of water and carbon dioxide into Earth's interior. Earth's internal structure is also related to its thermal state, the convective flow of material, and its evolution through time. There are few direct samples of rocks from the Earth's mantle, and even these give a highly incomplete view of Earth's mantle, down to only several hundred kilometers depth. By far, the most complete information we have on Earth's interior mantle and core come from seismology in the form of 3-D tomographic images of velocity structure. Interpretations of this seismological information in terms of, for example, chemical composition and thermal state, require laboratory measurements of sound velocities on the materials that are likely present at depth. However, such measurements at the extreme pressure-temperature conditions of Earth's interior are quite challenging and until recently were in most cases not technically feasible. This project will use recently-developed experimental facilities and techniques to measure the velocities of candidate mantle minerals at the actual pressures and temperatures of the Earth's mantle, from 30-2900 km depth. This project builds upon over a decade of NSF-funded technology development in the PI's laboratory which makes such measurements possible. The results of this project should give far better and more accurate understanding of the state of the Earth's mantle, placing far tighter constraints on its 3-D chemical composition, the nature of lateral and radial heterogeneity, and thermal structure. Technical advances made in the course of this project should be of great interest in cognate condensed matter sciences, and in materials engineering. This project will provide advanced scientific training for graduate students and a post-doctoral researcher, and should better enable them to pursue their career goals. This project will involve the measurement of sound velocities of candidate materials of Earth's mantle at extreme pressure-temperature conditions matching or close to those present in the mantle. Experiments will be performed by the technique of Brillouin light scattering on samples that are compressed in a diamond anvil cell (DAC). Silicate and oxide samples will be heated using a CO2 infrared laser to produce extreme simultaneous pressure-temperature conditions closely approximating actual mantle conditions. Measurements will be carried out on single-crystal samples where possible, thus giving information on velocity anisotropy which can be used to constrain dynamic flow of material at depth. Measurements will be performed on isotropic polycrystalline samples as well. Emphasis will be put on the most likely candidate phases of the upper mantle, transition zone, and lower mantle. The results of this project should place much tighter constraints on the chemical composition, mineralogy, and thermal structure of the mantle, including any possible radial chemical stratification and lateral chemical heterogeneity.
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/69661
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Jay Bass.Sound Velocities and Elastiicity of Deep-earth Materials at High Pressures and Temperature.2016.