Increased production of cosmogenic 10 Be recorded in oceanic sediment sequences: Information on the age, duration, and amplitude of the geomagnetic dipole moment minimum over the Matuyama–Brunhes transition

• Published in: Earth and Planetary Science Letters
• Main Authors: Simon, Quentin, Thouveny, Nicolas, Bourlès, Didier, Bassinot, Franck, Savranskaia, Tatiana, Valet, Jean-Pierre
• Other Authors: Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Paléocéanographie (PALEOCEAN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), INSU/CNRS; ANR through the EQUIPEX "ASTER-CEREGE" action; IRD; ERC advanced grant under the ERC's 7th Framework Program (FP7-IDEA-ERC), ANR-10-EQPX-0024,ASTER-CEREGE,PLATEFORME DE GEOCHIMIE ISOTOPIQUE ASTER/CEREGE(2010), European Project: 339899,EC:FP7:ERC,ERC-2013-ADG,EDIFICE(2014)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: authigenic Be-10/Be-9 ratio; geomagnetic dipole moment minimum; geomagnetic polarity reversal; marine isotope stage 19; atmospheric Be-10 production rates; Matuyama-Brunhes transition (MBT); [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Indian; Pacific; North Atlantic
• Online Access: https://hal.science/hal-01735837; https://hal.science/hal-01735837/document; https://hal.science/hal-01735837/file/1-s2.0-S0012821X18300980-main.pdf; https://doi.org/10.1016/j.epsl.2018.02.036

International audience New high-resolution authigenic Be-10/Be-9 ratio (Be-ratio) records covering the last geomagnetic reversal, i.e. the Matuyama-Brushes transition (MBT), have been obtained and set on a time scale using benthic delta O-18 (Cibicides wuellerstorfi) records. The geographic distribution of the four studied sites allows global comparison between the North Atlantic, Indian and Pacific Oceans. All Be-ratio records contain a twofold increase triggered by the geomagnetic dipole moment (GDM) collapse associated with the MBT. The stratigraphic position of the Be-ratio spike, relative to marine isotope stages, allows establishment of a robust astrochronological framework for the MBT, anchoring its age between 778 and 766 ka (average mid-peaks at 772 ka), which is consistent with all other available Be-10-proxy records from marine, ice and loess archives. The global Be-10 atmospheric production doubling represents an increase of more than 300 atoms m(-2) s(-1) that is compatible with the increased magnitude of atmospheric Be-10 production obtained by simulations between the present GDM and a null-GDM. The minimum Be-10-derived GDM average computed for the 776-771 ka interval is 1.7 +/- 0.4 x 10(22) Am-2, in agreement with model simulations and absolute paleointensities of transitional lava flows