DOI: 10.1038/ngeo2808
论文题名: Core merging and stratification following giant impact
作者: Landeau M. ; Olson P. ; Deguen R. ; Hirsh B.H.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 10 起始页码: 786
结束页码: 789
语种: 英语
Scopus关键词: core-mantle boundary
; geomagnetism
; metal
; Moon
; pressure effect
; seismic data
; silicate
; stratification
; temperature effect
; turbulent mixing
英文摘要: A stratified layer below the core-mantle boundary has long been suspected on the basis of geomagnetic and seismic observations. It has been suggested that the outermost core has a stratified layer about 100 km thick that could be due to the diffusion of light elements. Recent seismological evidence, however, supports a layer exceeding 300 km in thickness of enigmatic origin. Here we show from turbulent mixing experiments that merging between projectile and planetary core following a giant impact can lead to a stratified layer at the top of the core. Scaling relationships between post-impact core structure and projectile properties suggest that merging between Earth's protocore and a projectile core that is enriched in light elements and 20 times less massive can produce the thick stratification inferred from seismic data. Our experiments favour Moon-forming impact scenarios involving a projectile smaller than the proto-Earth and suggest that entrainment of mantle silicates into the protocore led to metal-silicate equilibration under extreme pressure-temperature conditions. We conclude that the thick stratified layer detected at the top of Earth's core can be explained as a vestige of the Moon-forming giant impact during the late stages of planetary accretion. © 2016 Macmillan Publishers Limited, part of Springer Nature.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105910
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 Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, United States; Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
Recommended Citation:
Landeau M.,Olson P.,Deguen R.,et al. Core merging and stratification following giant impact[J]. Nature Geoscience,2016-01-01,9(10)