气候变化领域集成服务门户(CCPortal): Seismic Visibility of Eclogite in the Earth’s Upper Mantle—Implications From High Pressure-Temperature Single-Crystal Elastic Properties of Omphacite

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DOI	10.1029/2021JB021683
	Seismic Visibility of Eclogite in the Earth’s Upper Mantle—Implications From High Pressure-Temperature Single-Crystal Elastic Properties of Omphacite
	Hao M.; Zhang J.S.; Zhou W.-Y.; Wang Q.
发表日期	2021
ISSN	21699313
卷号	126 期号:5
英文摘要	Identifying and locating the geochemical and geophysical heterogeneities in the Earth’s interior is one of the most important and challenging tasks for the deep Earth scientists. Subducted oceanic crust metamorphizes into the dense eclogite in the upper mantle and is considered as a major cause of geochemical and geophysical heterogeneities in the deep Earth. In order to detect eclogitic materials inside the Earth, precise measurements of the high pressure-temperature single-crystal elasticity of major minerals in eclogite are thus exceedingly important. Omphacite, a Na,Al-bearing clinopyroxene, constitutes up to 75 vol% of eclogite. In the present study, we performed the first high pressure-temperature single-crystal elasticity measurements of omphacite using Brillouin spectroscopy. Utilizing the finite-strain approach, we obtained the following thermoelastic parameters for omphacite: KS0’ = 4.5(1), G0’ = 1.53(5), ∂KS0/∂T = −0.029(5) GPa/K, ∂G0/∂T = −0.013(5) GPa/K, with KS0 = 123(3) GPa, G0 = 74(2) GPa, and ρ0 = 3.34(1) g/cm3. We found that the seismic velocities of undeformed eclogite are similar to pyrolite at the depths of 200–300 and 410–500 km, thus eclogite is seismically invisible at these depths. Combined with the lattice-preferred orientations of the omphacite in naturally deformed eclogites, we also modeled seismic anisotropy of eclogite at various pressure-temperature conditions. A 10 km thick subducted eclogitic crust can result in ∼0.2 s shear wave splitting in the Earth’s upper mantle. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	anisotropy; eclogite; elasticity; omphacite
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/187169
作者单位	Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, United States; Institute of Meteoritics, University of New Mexico, Albuquerque, NM, United States; School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
推荐引用方式 GB/T 7714	Hao M.,Zhang J.S.,Zhou W.-Y.,等. Seismic Visibility of Eclogite in the Earth’s Upper Mantle—Implications From High Pressure-Temperature Single-Crystal Elastic Properties of Omphacite[J],2021,126(5).
APA	Hao M.,Zhang J.S.,Zhou W.-Y.,&Wang Q..(2021).Seismic Visibility of Eclogite in the Earth’s Upper Mantle—Implications From High Pressure-Temperature Single-Crystal Elastic Properties of Omphacite.Journal of Geophysical Research: Solid Earth,126(5).
MLA	Hao M.,et al."Seismic Visibility of Eclogite in the Earth’s Upper Mantle—Implications From High Pressure-Temperature Single-Crystal Elastic Properties of Omphacite".Journal of Geophysical Research: Solid Earth 126.5(2021).