气候变化领域集成服务门户(CCPortal): Iron isotope fractionation at the core

CCPortal

DOI	10.1038/s41561-020-0560-y
	Iron isotope fractionation at the core–mantle boundary by thermodiffusion
	Lesher C.E.; Dannberg J.; Barfod G.H.; Bennett N.R.; Glessner J.J.G.; Lacks D.J.; Brenan J.M.
发表日期	2020
ISSN	17520894
起始页码	382
结束页码	386
卷号	13 期号:5
英文摘要	The D” layer at the base of the Earth’s mantle exhibits anomalous seismic properties, which are attributed to heat loss from and chemical interaction with the underlying molten Fe-rich outer core. Here we show that mass transfer due to temperature variations within the D” layer could lead to resolvable fractionation of iron isotopes. We constrain the degree of isotope fractionation by experiments on core-forming Fe alloy liquids at 2100–2300 K and 2 GPa, which demonstrate that heavy Fe isotopes preferentially migrate towards lower temperature and vice versa. We find that this isotope fractionation occurs rapidly due to the high mobility of iron, which reaches 0.013 ± 0.002‰ (2σ) per degree per amu at steady state. Numerical simulations of mantle convection capturing the evolution of a basal thermal boundary layer show that iron isotope fractionation immediately above the core–mantle boundary can reach measurable levels on geologic timescales and that plumes can entrain this fractionated material into the convecting mantle. We suggest that such a process may contribute to the heavy Fe isotope composition of the upper mantle inferred from mantle melts (basalts) and residues (peridotites) relative to chondrites. That being the case, non-traditional stable isotope systems such as Fe may constrain the interactions between the core and mantle. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.
英文关键词	boundary layer; core-mantle boundary; iron; isotopic composition; isotopic fractionation; mantle; mantle convection
语种	英语
来源期刊	Nature Geoscience
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/206803
作者单位	Department of Geoscience, Aarhus University, Aarhus, Denmark; Department of Earth and Planetary Sciences, University of California, Davis, CA, United States; Interdisciplinary Center for Plasma Mass Spectrometry, University of California, Davis, CA, United States; Department of Geological Sciences, University of Florida, Gainesville, FL, United States; Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, OH, United States; Department of Earth and Environmental Sciences, Dalhousie University, Halifax, NS, Canada
推荐引用方式 GB/T 7714	Lesher C.E.,Dannberg J.,Barfod G.H.,等. Iron isotope fractionation at the core–mantle boundary by thermodiffusion[J],2020,13(5).
APA	Lesher C.E..,Dannberg J..,Barfod G.H..,Bennett N.R..,Glessner J.J.G..,...&Brenan J.M..(2020).Iron isotope fractionation at the core–mantle boundary by thermodiffusion.Nature Geoscience,13(5).
MLA	Lesher C.E.,et al."Iron isotope fractionation at the core–mantle boundary by thermodiffusion".Nature Geoscience 13.5(2020).