EVIDENCE FOR ENHANCED BE-10 DEPOSITION IN MEDITERRANEAN SEDIMENTS 35-KYR BP

In this letter, we report the profiles (similar to 160 samples) of Be-10, Be-9, Zn in a Mediterranean sediment core spanning the last 60 kyr. We show the existence of a Be-10 peak, whose absolute age is estimated to be 34+/-3 kyr BP, based on its stratigraphic position between two tephra layers originating from two volcanic eruptions (Campanian Ignimbrite and Citara), dated by K-Ar, 40Ar-39Ar and C-14 methods. This peak is similar to the increase in the Be-10 concentration observed in Vostok and Dome C ice cores at the same age. The increase with approximately similar amplitude in both ice and sediment cores at different latitudes and hemispheres cannot be explained by changes in the archives. The present result supports the view of a well defined global enhancement of the Be-10 flux, related to an increase of the Be-10 production rate and not to a redistribution of the Be-10 fallout between different latitudes.