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DOI	10.1029/2020JB021261
	Coupled Brittle and Viscous Micromechanisms Produce Semibrittle Flow, Grain-Boundary Sliding, and Anelasticity in Salt-Rock
	Ding J.; Chester F.M.; Chester J.S.; Shen X.; Arson C.
发表日期	2021
ISSN	21699313
卷号	126 期号:2
英文摘要	The operation of fracture, diffusion, and intracrystalline-plastic micromechanisms during semibrittle deformation of rock is directly relevant to understanding mechanical behavior across the brittle-plastic transition in the crust. An outstanding question is whether (1) the micromechanisms of semibrittle flow can be considered to operate independently, as represented in typical crustal strength profiles across the brittle to plastic transition, or (2) the micromechanisms are coupled such that the transition is represented by a distinct rheology with dependency on effective pressure, temperature, and strain rate. We employ triaxial stress-cycling experiments to investigate elastic-plastic and viscoelastic behaviors during semibrittle flow in two distinctly different monomineralic, polycrystalline, synthetic salt-rocks. During semibrittle flow at high differential stress, granular, low-porosity, work-hardened salt-rocks deform predominantly by grain-boundary sliding and wing-crack opening accompanied by minor intragranular dislocation glide. In contrast, fully annealed, near-zero porosity salt-rocks flow at lower differential stress by intragranular dislocation glide accompanied by grain-boundary sliding and opening. Grain-boundary sliding is frictional during semibrittle flow at higher strain rates, but the associated dispersal of water from fluid inclusions along boundaries can activate fluid-assisted diffusional sliding at lower strain rates. Changes in elastic properties with semibrittle flow largely reflect activation of sliding along closed grain boundaries. Observed microstructures, pronounced hysteresis and anelasticity during cyclic stressing after semibrittle flow, and stress relaxation behaviors indicate coupled operation of micromechanisms leading to a distinct rheology (hypothesis 2 above). © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	anelasticity; brittle-plastic transition; grain boundary processes; rock rheology; salt-rock; semibrittle deformation
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/187386
作者单位	Center for Tectonophysics, Department of Geology & Geophysics, Texas A&M University, College Station, TX, United States; Current address: Department of Geophysics, Stanford University, Stanford, CA, United States; School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, United States; Current address: Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, United States
推荐引用方式 GB/T 7714	Ding J.,Chester F.M.,Chester J.S.,et al. Coupled Brittle and Viscous Micromechanisms Produce Semibrittle Flow, Grain-Boundary Sliding, and Anelasticity in Salt-Rock[J],2021,126(2).
APA	Ding J.,Chester F.M.,Chester J.S.,Shen X.,&Arson C..(2021).Coupled Brittle and Viscous Micromechanisms Produce Semibrittle Flow, Grain-Boundary Sliding, and Anelasticity in Salt-Rock.Journal of Geophysical Research: Solid Earth,126(2).
MLA	Ding J.,et al."Coupled Brittle and Viscous Micromechanisms Produce Semibrittle Flow, Grain-Boundary Sliding, and Anelasticity in Salt-Rock".Journal of Geophysical Research: Solid Earth 126.2(2021).