Data/hora: 12/06/2024 10:33:57

Provedor de dados: | 5
País: | France
Título: | Cosmogenic signature of geomagnetic reversals and excursions from the Réunion event to the Matuyama–Brunhes transition (0.7–2.14 Ma interval)
Autores: | Simon, Quentin; Bourles, Didier L.; Thouveny, Nicolas; Horng, Chorng-shern; Valet, Jean-pierre; Bassinot, Franck; Choy, Sandrine.
Data: | 2018-01
Ano: | 2018
Palavras-chave: | Authigenic Be-10/Be-9 ratios; Matuyama-Brunhes transition; Jaramillo and Olduvai subchrons; Cobb Mountain and Reunion events; Matuyama geomagnetic excursions; Lock-in depth.
Resumo: | Long-term variations of the geomagnetic dipole moment (GDM) during periods of stable polarity and in transitional states (reversals and excursions) provide key information for understanding the geodynamo regime. Following several studies dealing with the Brunhes chron and the Matuyama–Brunhes transition, this study presents a new authigenic 10Be/9Be ratio (Be-ratio) record obtained from the MD97-2143 core (western Pacific Ocean). This new Be-ratio series yields a record of GDM variations covering the early Brunhes and mid to late Matuyama time period (i.e. 700–2140ka), independently from the relative paleointensity (RPI) record obtained from the same core, that can be compared with available RPI records and stacks. Stratigraphic offsets measured between the Be-ratio peaks and the corresponding RPI minima reach 2 to 14cm. They can be assigned to (post-) detrital remanent magnetization (pDRM) effects leading to magnetization locking-in delays varying from 2 to 12ka in the studied core. 10Be overproduction episodes triggered by geomagnetic dipole moment lows (GDL) linked to polarity reversals and excursions confirm the global control exerted by the GDM on cosmogenic radionuclides production. A dipole moment reconstruction derived from the Beryllium-10 (BeDiMo) was compiled and calibrated using absolute paleointensity data. This independent record complements the available paleomagnetic RPI records, permitting 1) to overcome the pDRM lock-in offsets induced below the mixing layer, 2) to confront and increase the robustness and precision of GDM reconstructions and, 3) to better constrain the chronology of geomagnetic field instabilities during the mid to late Matuyama chron. Our new 10Be derived inventory is fully compatible with the GDL series linked to geomagnetic polarity reversals and events (Matuyama–Brunhes transition, Jaramillo and Olduvai subchron boundaries, Cobb Mountain, Réunion) and it strengthens the occurrence of several excursions (Kamikatsura, Santa Rosa, Punaruu, Bjorn, Gilsa, Gardar) that were until now reported from only sparse locations.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00414/52553/53381.pdf

https://archimer.ifremer.fr/doc/00414/52553/53382.xlsx

https://archimer.ifremer.fr/doc/00414/52553/53383.xlsx

https://archimer.ifremer.fr/doc/00414/52553/53384.xlsx

https://archimer.ifremer.fr/doc/00414/52553/53385.xlsx

https://archimer.ifremer.fr/doc/00414/52553/53386.pdf

https://archimer.ifremer.fr/doc/00414/52553/53387.pdf

https://archimer.ifremer.fr/doc/00414/52553/53388.pdf

https://archimer.ifremer.fr/doc/00414/52553/53389.pdf

DOI:10.1016/j.epsl.2017.11.021

https://archimer.ifremer.fr/doc/00414/52553/

Editor: | Elsevier Science Bv
Relação: | info:eu-repo/grantAgreement/EC/FP7/339899/EU//EDIFICE
Formato: | application/pdf
Fonte: | Earth And Planetary Science Letters (0012-821X) (Elsevier Science Bv), 2018-01 , Vol. 482 , P. 510-524

Fonte:

2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

info:eu-repo/semantics/openAccess

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