Scopus记录号: 2-s2.0-85060910727
论文题名: Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity
作者: Bono R.K. ; Tarduno J.A. ; Nimmo F. ; Cottrell R.D.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2019
卷: 12, 期: 2 起始页码: 143
结束页码: 147
语种: 英语
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 × 1022 A m2, 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. 资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122603
Appears in Collections: 气候变化事实与影响
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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
Recommended Citation:
Bono R.K.,Tarduno J.A.,Nimmo F.,et al. Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity[J]. Nature Geoscience,2019-01-01,12(2)