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| Carcaillet, Jt; Bourles, Dl; Thouveny, N. |
| A synthesis of authigenic Be-10/Be-9 ratio records constructed from sedimentary sequences deposited over the last 300 ka in the North East Atlantic and over the 500 - 1300 ka BP interval in the West Equatorial Pacific Ocean is compared with proxies of the geomagnetic moment variations over the same time intervals. These proxies consist in (1) relative paleointensity records obtained from the same sediments, (2) a seafloor magnetization record derived form magnetic anomalies, and (3) an absolute Virtual Dipole Moment (VDM) record constructed from an updated database of absolute paleointensities. The authigenic Be-10/Be-9 ratio records document the occurrence of the paleomagnetic events (excursions and reversals) reported for these time intervals by... |
| Tipo: Text |
Palavras-chave: Cosmogenic nuclide production rate; Beryllium; Paleointensity; Geomagnetic moment. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00229/34014/32371.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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