DOI: 10.1038/s41561-021-00761-w
论文题名: Dynamic history of the inner core constrained by seismic anisotropy
作者: Frost D.A. ; Lasbleis M. ; Chandler B. ; Romanowicz B.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2021
卷: 14, 期: 7 起始页码: 531
结束页码: 535
语种: 英语
英文关键词: alloy
; body wave
; brittle deformation
; crystallization
; Earth rotation
; geodynamics
; inner core
; iron
; nickel
; seismic anisotropy
; travel time
英文摘要: Progressive crystallization of Earth’s inner core drives convection in the outer core and magnetic field generation. Determining the rate and pattern of inner-core growth is thus crucial to understanding the evolution of the geodynamo. The growth history of the inner core is probably recorded in the distribution and strength of its seismic anisotropy, which arises from deformation texturing constrained by conditions at the inner-core solid–fluid boundary. Here we show from analysis of seismic body wave travel times that the strength of seismic anisotropy increases with depth within the inner core, and the strongest anisotropy is offset from Earth’s rotation axis. Then, using geodynamic growth models and mineral physics calculations, we simulate the development of inner-core anisotropy in a self-consistent manner. From this we find that an inner core composed of hexagonally close-packed iron–nickel alloy, deformed by a combination of preferential equatorial growth and slow translation, can match the seismic observations without requiring hemispheres with sharp boundaries. Our model of inner-core growth history is compatible with external constraints from outer-core dynamics, and supports arguments for a relatively young inner core (~0.5–1.5 Ga) and a viscosity >1018 Pa s. © 2021, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169747
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth & Planetary Science, University of California, Berkeley, CA, United States; Laboratoire de Planétologie et Géodynamique, Université de Nantes, CNRS, Nantes, France; Earth–Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan; Collège de France, Paris, France; Université de Paris, Institut de Physique du Globe de Paris, Paris, France
Recommended Citation:
Frost D.A.,Lasbleis M.,Chandler B.,et al. Dynamic history of the inner core constrained by seismic anisotropy[J]. Nature Geoscience,2021-01-01,14(7)