A GEOMAGNETIC CHRONOLOGY FOR ANTARCTIC ICE ACCUMULATION

The curve of Be-10 flux versus age in the Vostok ice core largely cova ries with a synthetic curve calculated assuming that a large fraction of Be-10 production rate is modulated by changes in the geomagnetic fi eld intensity. With this assumption, it is also possible to derive a. precise chronology for the Vostok core. This chronology is in good agr eement with a very recent glaciological chronology obtained for Vostok ice core, and improves the correspondence of climate events recorded in Antarctic ice with correlative events recorded in deep sea sediment s. Therefore, the idea that changes in the Be-10 flux at Vostok may ar ise from variations in Earth's geomagnetic dipole field has to be seri ously considered. This would imply that a large portion of the Be-10 d eposited there is derived from lower latitudes.