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DOI	10.1016/j.epsl.2020.116547
	Cosmogenic 10Be production records reveal dynamics of geomagnetic dipole moment (GDM) over the Laschamp excursion (20–60 ka)
	Simon Q.; Thouveny N.; Bourlès D.L.; Valet J.-P.; Bassinot F.
发表日期	2020
ISSN	0012821X
卷号	550
英文摘要	Documenting accurately amplitude and rhythms of geomagnetic variations is a prerequisite to understand the mechanisms triggering geomagnetic excursions and reversals. We present new authigenic 10Be/9Be ratio (Be ratio) results covering the 60–20 ka time interval from equatorial core MD05-2920. The most significant Be ratio peak is located 18 cm above the main relative paleointensity (RPI) minimum recorded in this sequence. These are interpreted as two independent recordings of the geomagnetic dipole moment (GDM) decrease linked to the Laschamp excursion dated at ca 41 ka. The stratigraphic offset is assignable to post-depositional magnetization lock-in processes resulting in time delay of 1.6 ka. The Be ratio and RPI records show comparable asymmetric behavior before and after the dipole low. The Be ratio record is combined with three other series to construct a global record of 10Be paleoproduction variations. This compilation demonstrates the strong coherence of low and mid latitudes data sets and its comparison with 10Be-flux records from polar regions fully supports the hypothesis of a global atmospheric 10Be production doubling during the Laschamp. The Be ratio stack is converted in terms of GDM using both a theoretical model and a reconstruction of GDM values using absolute paleointensities measured on lava flows. Both methods provide similar results. The dipole moment record derived from this approach (BeDM20–60) shows the following characteristics: high field values (>11×1022 Am2) prior to a sharp two-steps dipole decrease until reaching minimum values (1.8±0.7×1022 Am2) between 41.6 and 40.9 ka at the time of the Laschamp excursion. The GDM partly recovers up to values of ∼6.3×1022 Am2, and oscillates in this range, without showing any sharp decreases that could be associated with excursions reported within the 38–20 ka time interval (e.g. the Mono Lake excursion). © 2020 The Authors
关键词	atmospheric 10Be production authigenic 10Be/9Be ratio (Be ratio)geomagnetic dipole moment (GDM)Laschamp excursion lock-in depth relative paleointensity (RPI)
英文关键词	Dipole moment; Stratigraphy; Asymmetric behaviors; Geomagnetic dipole moment; Geomagnetic excursions; Geomagnetic variation; Laschamp excursions; Mono lake excursions; Relative paleointensity; Theoretical modeling; Geomagnetism; accuracy assessment; beryllium isotope; geomagnetic field; magnetic reversal; magnetization; paleointensity; paleomagnetism; reconstruction; trigger mechanism
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202889
作者单位	CEREGE UM34, Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, Aix en Provence, 13545, France; Institut de Physique du Globe de Paris, Sorbonne Paris-Cité, Université Paris Diderot, UMR 7154 CNRS, Paris, France; LSCE, UMR8212, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-Sur-Yvette, France
推荐引用方式 GB/T 7714	Simon Q.,Thouveny N.,Bourlès D.L.,等. Cosmogenic 10Be production records reveal dynamics of geomagnetic dipole moment (GDM) over the Laschamp excursion (20–60 ka)[J],2020,550.
APA	Simon Q.,Thouveny N.,Bourlès D.L.,Valet J.-P.,&Bassinot F..(2020).Cosmogenic 10Be production records reveal dynamics of geomagnetic dipole moment (GDM) over the Laschamp excursion (20–60 ka).Earth and Planetary Science Letters,550.
MLA	Simon Q.,et al."Cosmogenic 10Be production records reveal dynamics of geomagnetic dipole moment (GDM) over the Laschamp excursion (20–60 ka)".Earth and Planetary Science Letters 550(2020).