气候变化领域集成服务门户(CCPortal): Grain-Boundary Diffusion Creep of Olivine: 2. Solidus Effects and Consequences for the Viscosity of the Oceanic Upper Mantle

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DOI	10.1029/2020JB019416
	Grain-Boundary Diffusion Creep of Olivine: 2. Solidus Effects and Consequences for the Viscosity of the Oceanic Upper Mantle
	Yabe K.; Hiraga T.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	In Part 1 of this study (Yabe et al., 2020, https://doi.org/10.1029/2020JB019415), we established an olivine grain-boundary diffusion creep law that incorporates the chemically induced enhancement of creep rates, which becomes significant with increasing temperature. The effect was attributed to grain-boundary disordering that starts at ~0.92 × solidus (bulk eutectic temperature). In this study, we estimated solidus temperatures of the samples used in the previous diffusion creep experiments. These temperatures were used to compare previously reported diffusion creep rates for olivine with our established diffusion creep law. We found that the law explains a difference of up to 2 orders of magnitude in olivine creep rates at the same temperatures, stresses, grain sizes, and water contents in the previous studies. The geotherm normalized by the mantle solidus was calculated for the upper mantle with water contents ranging from 0 to 300 μg/g, which predicts depths where grain-boundary diffusion creep is enhanced due to grain-boundary disordering. Constructed viscosity-depth profiles reveal a very thin mantle lithosphere beneath mid-ocean ridges, with development of the lithosphere away from the ridge, leaving a low-viscosity region below. Given a grain size of 1 mm and depending on the water content, a viscosity of 2–5 × 1019 Pa·s is predicted for the low-viscosity mantle beneath 50-million-year-old seafloor. © 2020. American Geophysical Union. All Rights Reserved.
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/187708
作者单位	Earthquake Research Institute, The University of Tokyo, Tokyo, Japan
推荐引用方式 GB/T 7714	Yabe K.,Hiraga T.. Grain-Boundary Diffusion Creep of Olivine: 2. Solidus Effects and Consequences for the Viscosity of the Oceanic Upper Mantle[J],2020,125(8).
APA	Yabe K.,&Hiraga T..(2020).Grain-Boundary Diffusion Creep of Olivine: 2. Solidus Effects and Consequences for the Viscosity of the Oceanic Upper Mantle.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Yabe K.,et al."Grain-Boundary Diffusion Creep of Olivine: 2. Solidus Effects and Consequences for the Viscosity of the Oceanic Upper Mantle".Journal of Geophysical Research: Solid Earth 125.8(2020).