DOI: 10.1016/j.epsl.2019.115999
论文题名: Deformation of polycrystalline D2O ice: Its sensitivity to temperature and strain-rate as an analogue for terrestrial ice
作者: Wilson C.J.L. ; Peternell M. ; Hunter N.J.R. ; Luzin V.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 532 语种: 英语
中文关键词: crystallographic preferred orientation
; deuterated ice
; grain-size evolution
; microstructure
; strain-rate
; texture
英文关键词: Deformation
; Deuterium
; Dynamic recrystallization
; Glaciers
; Grain boundaries
; Grain size and shape
; Ice
; Microstructure
; Neutron diffraction
; Structural geology
; Textures
; Continuous monitoring
; Crystallographic preferred orientations
; Deformation mechanism
; Grain boundary migrations
; Grain size
; In-situ neutron diffraction
; Sensitivity to temperatures
; Strain rate dependence
; Strain rate
; crystalline rock
; crystallography
; deformation mechanism
; displacement
; grain size
; microstructure
; preferred orientation
; sensitivity analysis
; strain rate
; temperature effect
英文摘要: Polycrystalline deuterated ice (D2O) was deformed over a range of high-temperatures (−20 to −1 °C; 0.92–0.99Tm) during in situ neutron diffraction texture and grain-size analysis. This allowed for a continuous monitoring of the evolution of rheology, texture, grain-numbers and the type of microstructures, which are compared to those encountered in basal sections of ice-sheets. We quantify the textural evolution with J-index changes as a function of strain-rate and temperature. Three sets of unconfined samples were deformed at displacement rates of 1×10−5 s−1 (fast) 2.5×10−6 s−1 (medium) and 6×10−7 s−1 (slow). Dislocation creep is proposed as the main deformation mechanism with sub-grain rotation more significant at lower temperatures (0.92Tm) and/or higher strain-rates. At higher-temperatures (0.99Tm) and/or lower strain-rates dynamic recrystallization is dominated by grain boundary migration, typified by grains with highly curved or lobate grain boundaries, and leading to rheological softening of the ice. From initially randomly oriented [c]-axes, a texture comprising 30–35° cones parallel to the compression axis develops, which is comparable to textures observed in the upper levels of polar ice-sheets. There is also a strain-rate dependence on the development of normalized [c]-axis intensities, which is in competition with strain magnitude and temperature. At lower temperatures (≤10 °C), small increments of strain or slower strain-rates, the cone-angle and textural strength decrease with a dominant textural component parallel to the compression axis. This may be an explanation for the vertical [c]-axis concentrations observed in polar ice cores. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165346
Appears in Collections: 气候变化与战略
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作者单位: School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia; Department of Earth Sciences, University of Gothenburg, SE-40 530, Sweden; Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
Recommended Citation:
Wilson C.J.L.,Peternell M.,Hunter N.J.R.,et al. Deformation of polycrystalline D2O ice: Its sensitivity to temperature and strain-rate as an analogue for terrestrial ice[J]. Earth and Planetary Science Letters,2020-01-01,532