Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments
Authigenic 10Be/9Be ratios were measured along a sediment core collected in the west equatorial Pacific in order to reconstruct cosmogenic 10Be production variations near the equator, where the geomagnetic modulation is maximum. From 60 to 20 ka, the single significant 10Be production impulse record...
Published in: | Journal of Geophysical Research: Solid Earth |
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Online Access: | https://hal.archives-ouvertes.fr/hal-01238834 https://doi.org/10.1029/2012JB009256 |
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ftccsdartic:oai:HAL:hal-01238834v1 2023-05-15T16:30:12+02:00 Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments Menabreaz, Lucie BOURLES, Didier Thouveny, Nicolas Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA) 2012-11-08 https://hal.archives-ouvertes.fr/hal-01238834 https://doi.org/10.1029/2012JB009256 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JB009256 hal-01238834 https://hal.archives-ouvertes.fr/hal-01238834 doi:10.1029/2012JB009256 ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.archives-ouvertes.fr/hal-01238834 Journal of Geophysical Research, American Geophysical Union, 2012, 117, pp.B11101. ⟨10.1029/2012JB009256⟩ [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] info:eu-repo/semantics/article Journal articles 2012 ftccsdartic https://doi.org/10.1029/2012JB009256 2021-10-24T11:08:54Z Authigenic 10Be/9Be ratios were measured along a sediment core collected in the west equatorial Pacific in order to reconstruct cosmogenic 10Be production variations near the equator, where the geomagnetic modulation is maximum. From 60 to 20 ka, the single significant 10Be production impulse recorded at 41 ka results from the geomagnetic dipole low that triggered the Laschamp excursion. No significant 10Be overproduction signature is recorded at the age of the Mono Lake excursion (∼34 ka). A compilation of authigenic 10Be/9Be records obtained from sediments was averaged over a 1 kyr window and compared with the 1 kyr averaged 10Be flux record of Greenland ice cores. Their remarkable similarity demonstrates that 10Be production is globally modulated by geomagnetic dipole variations and redistributed by atmosphere dynamics. After calibration using absolute values of the virtual dipole moment drawn from paleomagnetic database, the authigenic 10Be/9Be stack allows reconstructing the geomagnetic dipole moment variations over the 20–50 ka time interval. Between 48 and 41 ka, the dipole moment collapsed at a rate of −1.5 × 1022 A m2 kyr−1, which will be an interesting criterion for the assessment of the loss rate of the historical field and the comparison of dipole moment loss prior to excursions and reversals. After a 2 kyr duration of the minimum dipole moment (∼1 × 1022 A m2), a slow increase started at 39 ka, progressively reaching 5 × 1022 A m2 at 20 ka. The absence of a significant dipole moment drop at 34 ka, the age of the Mono lake excursion, suggests that the duration and amplitude of the dipole weakening cannot be compared with that of the Laschamp. This study provides a reliable basis to model the production of radiocarbon and in situ cosmogenic nuclides and to improve the calibration of these dating methods Article in Journal/Newspaper Greenland Greenland ice cores Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Greenland Pacific Journal of Geophysical Research: Solid Earth 117 B11 n/a n/a |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
spellingShingle |
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] Menabreaz, Lucie BOURLES, Didier Thouveny, Nicolas Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
topic_facet |
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
description |
Authigenic 10Be/9Be ratios were measured along a sediment core collected in the west equatorial Pacific in order to reconstruct cosmogenic 10Be production variations near the equator, where the geomagnetic modulation is maximum. From 60 to 20 ka, the single significant 10Be production impulse recorded at 41 ka results from the geomagnetic dipole low that triggered the Laschamp excursion. No significant 10Be overproduction signature is recorded at the age of the Mono Lake excursion (∼34 ka). A compilation of authigenic 10Be/9Be records obtained from sediments was averaged over a 1 kyr window and compared with the 1 kyr averaged 10Be flux record of Greenland ice cores. Their remarkable similarity demonstrates that 10Be production is globally modulated by geomagnetic dipole variations and redistributed by atmosphere dynamics. After calibration using absolute values of the virtual dipole moment drawn from paleomagnetic database, the authigenic 10Be/9Be stack allows reconstructing the geomagnetic dipole moment variations over the 20–50 ka time interval. Between 48 and 41 ka, the dipole moment collapsed at a rate of −1.5 × 1022 A m2 kyr−1, which will be an interesting criterion for the assessment of the loss rate of the historical field and the comparison of dipole moment loss prior to excursions and reversals. After a 2 kyr duration of the minimum dipole moment (∼1 × 1022 A m2), a slow increase started at 39 ka, progressively reaching 5 × 1022 A m2 at 20 ka. The absence of a significant dipole moment drop at 34 ka, the age of the Mono lake excursion, suggests that the duration and amplitude of the dipole weakening cannot be compared with that of the Laschamp. This study provides a reliable basis to model the production of radiocarbon and in situ cosmogenic nuclides and to improve the calibration of these dating methods |
author2 |
Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA) |
format |
Article in Journal/Newspaper |
author |
Menabreaz, Lucie BOURLES, Didier Thouveny, Nicolas |
author_facet |
Menabreaz, Lucie BOURLES, Didier Thouveny, Nicolas |
author_sort |
Menabreaz, Lucie |
title |
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
title_short |
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
title_full |
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
title_fullStr |
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
title_full_unstemmed |
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric Be-10 overproduction: Contribution of authigenic Be-10/Be-9 ratios in west equatorial Pacific sediments |
title_sort |
amplitude and timing of the laschamp geomagnetic dipole low from the global atmospheric be-10 overproduction: contribution of authigenic be-10/be-9 ratios in west equatorial pacific sediments |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.archives-ouvertes.fr/hal-01238834 https://doi.org/10.1029/2012JB009256 |
geographic |
Greenland Pacific |
geographic_facet |
Greenland Pacific |
genre |
Greenland Greenland ice cores |
genre_facet |
Greenland Greenland ice cores |
op_source |
ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.archives-ouvertes.fr/hal-01238834 Journal of Geophysical Research, American Geophysical Union, 2012, 117, pp.B11101. ⟨10.1029/2012JB009256⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JB009256 hal-01238834 https://hal.archives-ouvertes.fr/hal-01238834 doi:10.1029/2012JB009256 |
op_doi |
https://doi.org/10.1029/2012JB009256 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
117 |
container_issue |
B11 |
container_start_page |
n/a |
op_container_end_page |
n/a |
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1766019919195930624 |