¹⁰Be in ice at Vostok Antarctica during the last climatic cycle

Abstract

We have previously reported accelerator mass spectrometer measurements of the cosmogenic isotope ¹⁰Be (half life 1.5 Myr) in an 906-m ice core recovered at Dome C, Antarctica¹. In addition to an enhanced concentration during a period of reduced solar activity (Maunder minimum, AD 1645–1715)², we found substantially increased concentrations during that part of the core corresponding to the last ice age. Both effects have been confirmed and extended in Greenland ice cores^3,4. The recovery of a 2,083-m ice core at Vostok, Antarctica⁵, together with an extended oxygen isotope chronology reported elsewhere in this issue⁶, permits an extension of ¹⁰Be studies over the whole of the last climatic cycle (∼ 125 kyr). We report here such measurements, which show an excellent correlation with the oxygen isotope and thus, presumably, climate record over the whole of this period. The results imply that precipitation rates in the Antarctic during the last interglacial were similar to those of the Holocene, but were roughly halved during the last glaciation.