气候变化领域集成服务门户(CCPortal): Evolution of Microstructural Properties in Sheared Iron-Rich Olivine

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DOI	10.1029/2020JB019629
	Evolution of Microstructural Properties in Sheared Iron-Rich Olivine
	Qi C.; Zhao Y.-H.; Zimmerman M.E.; Kim D.; Kohlstedt D.L.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	Iron-rich olivine is mechanically weaker than olivine of mantle composition, ca. Fo90, and thus is more amenable to study under a wide range of laboratory conditions. To investigate the effects of iron content on deformation-produced crystallographic preferred orientation (CPO) and grain size, we analyzed the microstructures of olivine samples with compositions of Fo70, Fo50, and Fo0 that were deformed in torsion under either anhydrous or hydrous conditions at 300 MPa. Electron backscatter diffraction (EBSD) observations reveal a transition in CPO from D-type fabric, induced by dislocation glide on both the (010)[100] and the (001)[100] slip systems, at low strains, to A-type fabric, caused by dislocation glide on the (010)[100] slip system, at high strains for all of our samples, independent of iron content and hydrous/anhydrous conditions. A similar evolution of fabric with increasing strain is also reported to occur for Fo90. Radial seismic anisotropy increases with increasing strain, reaching a maximum value of ∼1.15 at a shear strain of ∼3.5 for each sample, demonstrating that the seismic anisotropy of naturally deformed olivine-rich rocks can be well approximated by that of iron-rich olivine. Based on EBSD observations, we derived a piezometer for which recrystallized grain size decreases inversely with stress to the ∼1.2 power. Also, recrystallized grain size increases with increasing iron content. Our experimental results contribute to understanding the microstructural evolution in the mantle of not only Earth but also Mars, where the iron content in olivine is higher. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	crystallographic preferred orientation; grain size; olivine; piezometer
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187308
作者单位	Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; Department of Geophysics, Peking University, Beijing, China; Department of Earth & Environmental Sciences, University of Minnesota, Minneapolis, MN, United States; Division of Polar Earth-System Sciences, Korea Polar Research Institute, Incheon, South Korea
推荐引用方式 GB/T 7714	Qi C.,Zhao Y.-H.,Zimmerman M.E.,et al. Evolution of Microstructural Properties in Sheared Iron-Rich Olivine[J],2021,126(3).
APA	Qi C.,Zhao Y.-H.,Zimmerman M.E.,Kim D.,&Kohlstedt D.L..(2021).Evolution of Microstructural Properties in Sheared Iron-Rich Olivine.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Qi C.,et al."Evolution of Microstructural Properties in Sheared Iron-Rich Olivine".Journal of Geophysical Research: Solid Earth 126.3(2021).