Increased production of cosmogenic 10Be 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, Bourles, Didier L., Bassinot, Franck, Savranskaia, Tatiana, Valet, Jean-pierre
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2018
• Subjects: authigenic Be-10/Be-9 ratio; geomagnetic dipole moment minimum; Matuyama-Brunhes transition (MBT); geomagnetic polarity reversal; marine isotope stage 19; atmospheric Be-10 production rates; Indian; Pacific; North Atlantic
• Online Access: https://archimer.ifremer.fr/doc/00430/54150/55510.pdf; https://archimer.ifremer.fr/doc/00430/54150/55511.xlsx; https://archimer.ifremer.fr/doc/00430/54150/55512.xlsx; https://archimer.ifremer.fr/doc/00430/54150/55513.xlsx; https://archimer.ifremer.fr/doc/00430/54150/55514.xlsx; https://archimer.ifremer.fr/doc/00430/54150/55515.xlsx; https://doi.org/10.1016/j.epsl.2018.02.036; https://archimer.ifremer.fr/doc/00430/54150/

New high-resolution authigenic 10Be/9Be ratio (Be-ratio) records covering the last geomagnetic reversal, i.e. the Matuyama–Brunhes transition (MBT), have been obtained and set on a time scale using benthic δ18 O (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 two-fold 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 10Be-proxy records from marine, ice and loess archives. The global 10Be atmospheric production doubling represents an increase of more than 300 atoms m−2 s−1 that is compatible with the increased magnitude of atmospheric 10Be production obtained by simulations between the present GDM and a null-GDM. The minimum 10Be-derived GDM average computed for the 776–771 ka interval is 1.7±0.4×10 22 Am2, in agreement with model simulations and absolute paleointensities of transitional lava flows.