Article Dans Une Revue Quaternary Science Reviews Année : 2025

Geomagnetic moment variation over the last 4.4 Million years through high resolution paleointensity and 10Be production records along ocean sediment sequences

Résumé

Beryllium-10 measurements along the northern Pacific sediment core collected from ODP site 1021 covering the interval 1.2–4.4 Millions of years (Ma) have been combined with previously published records of the last 1.2 Ma, in order to build the first 10Be/9Be (Be-ratio) record over the past 4.4 Ma. This new proxy-record of the dipole moment variation is compared with relative paleointensity (RPI) stacks. Together with the recent GTS timescale and δ18O composite curves, these records allow to compare and discuss the timings of field intensity and climatic changes over the last 5 Ma. We observe that in the last 3.2 Ma, i.e. the most precisely dated time interval, 8 over 9 reversals occurred near the culmination of interstadial or interglacial stages. The age models uncertainties as well as the eventual biases affecting the proxies series are analyzed, but their implication in this striking coincidence can reasonably be discarded. The possible influence of the obliquity on the geomagnetic field as well as the influence of the geomagnetic field on the climate are discussed in the light of former studies. Both hypotheses remain unanswered and controversial.

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Dates et versions

hal-05042214 , version 1 (22-04-2025)

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Citer

Jean-Pierre Valet, Tatiana Savranskaia, Quentin Simon, Ramon Egli, Franck Bassinot, et al.. Geomagnetic moment variation over the last 4.4 Million years through high resolution paleointensity and 10Be production records along ocean sediment sequences. Quaternary Science Reviews, 2025, 359, pp.109367. ⟨10.1016/j.quascirev.2025.109367⟩. ⟨hal-05042214⟩
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