過去7千年間の南極におけるベリリウム10

Since the first measurements of beryllium 10 (¹⁰Be) in ice, in the seventies, numerous profiles of this cosmogenic isotope have been obtained both in Antarctica and Greenland. In this article, we focus on Antarctic data, available at nine different sites, covering a significant part of the Holocene, from 237 to 7101 yr BP. We show that correlating their ¹⁰Be profiles allows to synchronize these ice cores with an excellent accuracy and to document the spatial variability of ¹⁰Be concentration and flux. We then examine how this variability is taken into account by a simulation of ¹⁰Be fallout recently performed with the ECHAM6.3-HAM2.3 model. Except for a systematic underestimation of ¹⁰Be fluxes at high accumulation sites, these simulations are overall very satisfying. Finally the excellent accuracy of synchronisation based on ¹⁰Be profiles allows us to derive an Antarctic stack record over the last seven millennia. The reliability of the new ¹⁰Be stack is demonstrated by its superior correspondence with the accurately dated IntCal20 record based on ¹⁴C in tree rings.