气候变化领域集成服务门户(CCPortal): Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity

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DOI	10.1038/s41561-018-0288-0
	Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity
	Bono R.K.; Tarduno J.A.; Nimmo F.; Cottrell R.D.
发表日期	2019
ISSN	17520894
卷号	12 期号:2
英文摘要	An enduring mystery about Earth has been the age of its solid inner core. Plausible yet contrasting core thermal conductivity values lead to inner core growth initiation ages that span 2 billion years, from ~0.5 to >2.5 billion years ago. Palaeomagnetic data provide a direct probe of past core conditions, but heretofore field strength data were lacking for the youngest predicted inner core onset ages. Here we present palaeointensity data from the Ediacaran (~565 million years old) Sept-Îles intrusive suite measured on single plagioclase and clinopyroxene crystals that hosted single-domain magnetic inclusions. These data indicate a time-averaged dipole moment of ~0.7 × 10 22 A m 2 , the lowest value yet reported for the geodynamo from extant rocks and more than ten times smaller than the strength of the present-day field. Palaeomagnetic directional studies of these crystals define two polarities with an unusually high angular dispersion (S = ~26°) at a low latitude. Together with 14 other directional data sets that suggest a hyper-reversal frequency, these extraordinary low field strengths suggest an anomalous field behaviour, consistent with predictions of geodynamo simulations, high thermal conductivities and an Ediacaran onset age of inner core growth. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
语种	英语
scopus关键词	clinopyroxene; Ediacaran; geodynamo; geomagnetic field; inner core; paleointensity; paleomagnetism; plagioclase; simulation; thermal conductivity
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/124714
作者单位	Department of Earth & Environmental Sciences, University of Rochester, Rochester, NY, United States; Department of Physics & Astronomy, University of Rochester, Rochester, NY, United States; Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA, United States; Geomagnetism Laboratory, University of Liverpool, Liverpool, United Kingdom
推荐引用方式 GB/T 7714	Bono R.K.,Tarduno J.A.,Nimmo F.,et al. Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity[J],2019,12(2).
APA	Bono R.K.,Tarduno J.A.,Nimmo F.,&Cottrell R.D..(2019).Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity.Nature Geoscience,12(2).
MLA	Bono R.K.,et al."Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity".Nature Geoscience 12.2(2019).