Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric 10 Be overproduction: Contribution of authigenic 10 Be/ 9 Be ratios in west equatorial Pacific sediments

摘要: [1] Authigenic 10Be/9Be ratios were measured along a sediment core collected in the west equatorial Pacific order to reconstruct cosmogenic 10Be production variations near equator, where geomagnetic modulation is maximum. From 60 20 ka, single significant impulse recorded at 41 ka results from dipole low that triggered Laschamp excursion. No overproduction signature age of Mono Lake excursion (∼34 ka). A compilation authigenic records obtained sediments was averaged over 1 kyr window and compared with flux record Greenland ice cores. Their remarkable similarity demonstrates globally modulated by redistributed atmosphere dynamics. After calibration using absolute values virtual moment drawn paleomagnetic database, stack allows reconstructing 20–50 time interval. Between 48 collapsed rate −1.5 × 1022 m2 kyr−1, which will be an interesting criterion for assessment loss historical field comparison prior excursions reversals. 2 duration minimum (∼1 m2), slow increase started 39 progressively reaching 5 ka. The absence drop 34 lake excursion, suggests amplitude weakening cannot Laschamp. This study provides reliable basis model radiocarbon situ nuclides improve these dating methods.