Atmospheric ¹⁰Be from Talos Dome (East Antarctic) ice core records geomagnetic dipole intensity from 170 to 270 ka BP

Abstract. We present high-resolution ¹⁰Be concentration and flux records from the Talos Dome ice core (East Antarctica), covering the period from 170 to 270 ka BP, to assess the capacity of Antarctic ice cores to capture the dipole moment reductions triggered by geomagnetic excursions of different amplitudes. Three distinct geomagnetic events are identified in the ¹⁰Be flux. The dipole collapse linked to the Iceland Basin Excursion (IBE) is clearly recorded as a ¹⁰Be peak flux 1.59 to 2.08 times above background between (192.0 ± 1.4) ka BP and (185.6 ± 1.4) ka BP. A clear asymmetric structure is observed, with a rapid decline of the geomagnetic dipole, followed by a three-step recovery. Two dipole decreases of lower amplitude are also resolved in relation with the Pringle Falls Excursion (PFE), lasting from (218.5 ± 1.90) to (206.0 ± 0.8) ka BP, and the Mamaku Excursion (ME), identified at (242.0 ± 0.3) ka BP, both showing an increase of the ¹⁰Be flux by a factor of 1.24 to 1.63. A total of 52 short-term ¹⁰Be concentration minima were also identified and are consistently associated with peaks in major ion concentrations, indicating post-depositional effects that affect concentration but not the longer-term flux signal. Comparison with Dome Fuji ice core and oceanic authigenic ¹⁰Be/⁹Be records reveals strong agreement in the timing and structure of the dipole moment collapses linked with these excursions. These results further support the use of ¹⁰Be for synchronizing ice and marine archives as well as to reconstruct past geomagnetic dipole moment variations and refining age models over the Pleistocene.