DOI: 10.1038/ngeo1808
论文题名: Strength of iron at core pressures and evidence for a weak Earth's inner core
作者: Gleason A.E. ; Mao W.L.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2013
卷: 6, 期: 7 起始页码: 571
结束页码: 574
语种: 英语
Scopus关键词: deformation mechanism
; dislocation
; experimental study
; geophysical survey
; inner core
; iron
; pressure gradient
; rheology
; shear strength
; temperature effect
; X-ray diffraction
; X-ray spectroscopy
英文摘要: The strength of iron at extreme conditions is crucial information for interpreting geophysical observations of the Earth's core and understanding how the solid inner core deforms. However, the strength of iron, on which deformation depends, is challenging to measure and accurately predict at high pressure. Here we present shear strength measurements of iron up to pressures experienced in the Earth's core. Hydrostatic X-ray spectroscopy and non-hydrostatic radial X-ray diffraction measurements of the deviatoric strain in hexagonally close-packed iron uniquely determine its shear strength to pressures above 200 GPa at room temperature. Applying numerical modelling of the rheologic behaviour of iron under pressure, we extrapolate our experimental results to inner-core pressures and temperatures, and find that the bulk shear strength of hexagonally close-packed iron is only ∼ 1 GPa at the conditions of the Earth's centre, 364 GPa and 5,500 K. This suggests that the inner core is rheologically weak, which supports dislocation creep as the dominant creep mechanism influencing deformation. © 2013 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106742
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States; Photon Science, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States
Recommended Citation:
Gleason A.E.,Mao W.L.. Strength of iron at core pressures and evidence for a weak Earth's inner core[J]. Nature Geoscience,2013-01-01,6(7)