10Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core.
An ice core drilled at Dome C, Antarctica, is the oldest ice core so far retrieved. On the basis of ice flow modelling and a comparison between the deuterium signal in the ice with climate records from marine sediment cores, the ice at a depth of 3,190 m in the Dome C core is believed to have been deposited around 800,000 years ago, offering a rare opportunity to study climatic and environmental conditions over this time period. However, an independent determination of this age is important because the deuterium profile below a depth of 3,190 m depth does not show the expected correlation with the marine record. Here we present evidence for enhanced 10Be deposition in the ice at 3,160-3,170 m, which we interpret as a result of the low dipole field strength during the Matuyama-Brunhes geomagnetic reversal, which occurred about 780,000 years ago. If correct, this provides a crucial tie point between ice cores, marine cores and a radiometric timescale.
Raisbeck
G M
GM
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, IN2P3-CNRS-Université de Paris-Sud, Bât. 108, 91405 Orsay, France. raisbeck@csnsm.in2p3.fr
Yiou
F
F
Cattani
O
O
Jouzel
J
J