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| Simon, Quentin; Thouveny, Nicolas; Bourles, Didier L.; Bassinot, Franck; Savranskaia, Tatiana; Valet, Jean-pierre. |
| 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... |
| Tipo: Text |
Palavras-chave: 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. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00430/54150/55510.pdf |
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| Savranskaia, Tatiana; Egli, Ramon; Valet, Jean-pierre; Bassinot, Franck; Meynadier, Laure; Bourlès, Didier L.; Simon, Quentin; Thouveny, Nicolas. |
| Reconstructions of the global production rate of the cosmogenic isotope 10Be from sedimentary records of authigenic 10Be/9Be ratios have been successfully used to obtain independent estimates of geomagnetic dipole moment variations caused by field excursions or reversals. In this study, we assess the reliability of 10Be/9Be as a proxy for the cosmogenic 10Be production rate by evaluating two potential biasing sources represented by sediment composition and climatic modulation. For this purpose, we compare five high-resolution 10Be/9Be records of the Matuyama-Brunhes (M-B) field reversal from sediment cores of the Indian, West Pacific, and North Atlantic oceans. Significant increase of 10Be/9Be ratios at 774 ka is explained in terms of the dominant control... |
| Tipo: Text |
Palavras-chave: Cosmogenic nuclides; Beryllium; Authigenic; 10Be/9Be ratio; Geomagnetic field intensity; Matuyama-brunhes reversal. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79399/81939.pdf |
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