中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Magnesium partitioning between silicate melt and liquid iron using first-principles molecular dynamics: Implications for the early thermal history of the Earth's core

文献类型:期刊论文

作者Liu, Weiyi1,4; Zhang, Yigang1,3; Yin, Qing-Zhu2; Zhao, Yong1,4,5; Zhang, Zhigang1,4,5
刊名EARTH AND PLANETARY SCIENCE LETTERS
出版日期2020-02-01
卷号531页码:12
ISSN号0012-821X
关键词geodynamo Mg core ab initio paleomagnetism giant impact
DOI10.1016/j.epsl.2019.115934
英文摘要The high conductivity of the Earth's core discovered through first-principles and experimental studies requires that the core must start very hot and cool down slowly to generate the Earth's magnetic field by thermal buoyancy. The requirement is difficult to satisfy due to the fast cooling of the overlying magma ocean and consequently of the underlying core. This is in direct conflict with the early appearance of the Earth's paleomagnetic field. Recently, it was proposed that significant amount of magnesium (Mg) can be partitioned into the core through the high temperature created by the Moon-forming Giant Impact. Due to its intrinsic low solubility, subsequent cooling would cause Mg precipitation to generate compositional buoyancy to power the geodynamo in the early history of the Earth. Here we show using first-principles molecular dynamics simulations that the equilibrium constant of magnesium dissolution in molten iron depends on temperature, entirely consistent with recent experimental data. We further show that Mg partitioned into the core during giant impacts and reaching a concentration of about 2 wt% can precipitate out at around 3.5 Ga, much earlier than the onset of inner core nucleation. During the subsequent evolution of the Earth, silicon (Si) concentration of the Earth's core will remain constant while Mg and oxygen (O) concentrations decrease significantly. Consequently, the current Si concentration in the core reflects the accretion processes of the Earth while O and Mg concentrations in the core is the combined result of both accretion and the subsequent evolution of the Earth core. Forward modeling shows that for MgO precipitation to provide enough power to generate the magnetic field in the early history of the Earth, initially high silicon content of the core is preferred, which is accommodated readily in the Grand Tack accretion scenario. The geodynamo driven by MgO precipitation explains the secular decline of palaeomagnetic field intensity in the early history of the Earth. (C) 2019 Elsevier B.V. All rights reserved.
WOS关键词HIGH-PRESSURE ; ELECTRICAL-RESISTIVITY ; MOLTEN IRON ; OXYGEN ; CONSTRAINTS ; EVOLUTION ; POTASSIUM ; NI ; DIFFERENTIATION ; PRECIPITATION
资助项目Strategic Priority Research Program (B) of the Chinese Academy of Sciences[XDB18000000] ; National Science Foundation of China[41273078]
WOS研究方向Geochemistry & Geophysics
语种英语
出版者ELSEVIER
WOS记录号WOS:000510947100008
资助机构Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China ; National Science Foundation of China
源URL[http://ir.iggcas.ac.cn/handle/132A11/95676]  
专题地质与地球物理研究所_中国科学院地球与行星物理重点实验室
通讯作者Yin, Qing-Zhu
作者单位1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing 100029, Peoples R China
2.Univ Calif Davis, Dept Earth & Planetary Sci, Davis, CA 95616 USA
3.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Key Lab Computat Geodynam, Beijing 100049, Peoples R China
4.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing 100029, Peoples R China
5.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
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GB/T 7714
Liu, Weiyi,Zhang, Yigang,Yin, Qing-Zhu,et al. Magnesium partitioning between silicate melt and liquid iron using first-principles molecular dynamics: Implications for the early thermal history of the Earth's core[J]. EARTH AND PLANETARY SCIENCE LETTERS,2020,531:12.
APA Liu, Weiyi,Zhang, Yigang,Yin, Qing-Zhu,Zhao, Yong,&Zhang, Zhigang.(2020).Magnesium partitioning between silicate melt and liquid iron using first-principles molecular dynamics: Implications for the early thermal history of the Earth's core.EARTH AND PLANETARY SCIENCE LETTERS,531,12.
MLA Liu, Weiyi,et al."Magnesium partitioning between silicate melt and liquid iron using first-principles molecular dynamics: Implications for the early thermal history of the Earth's core".EARTH AND PLANETARY SCIENCE LETTERS 531(2020):12.

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来源:地质与地球物理研究所

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