The curve of 10Be flux versus age in the Vostok ice core largely covaries with a synthetic curve calculated assuming that a large fraction of 10Be production rate is modulated by changes in the geomagnetic field intensity. With this assumption, it is also possible to derive a precise chronology for the Vostok core. This chronology is in good agreement 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 sediments. Therefore, the idea that changes in the 10Be flux at Vostok may arise from variations in Earth's geomagnetic dipole field has to be seriously considered. This would imply that a large portion of the 10Be deposited there is derived from lower latitudes.