Early Holocene climate oscillations recorded in three Greenland ice cores

Quaternary Science Reviews, in press, 2007
S.O. Rasmussen, B.M. Vinther, H.B. Clausen and K.K. Andersen
Ice and Climate, The Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark

A new ice core chronology for the Greenland DYE-3, GRIP, and NGRIP ice cores has been constructed, making it possible to compare the δ18O and accumulation signals recorded in the three cores on an almost annual scale throughout the Holocene. We here introduce the new time scale and investigate δ18O and accumulation anoma- lies that are common to the three cores in the Early Holocene (7.9-11.7 ka before present). Three time periods with significant and synchronous anomalies in the δ18O and accumulation signals stand out: the well known 8.2 ka event, an event of shorter duration but of almost similar amplitude around 9.3 ka before present, and the Preboreal Oscillation in the first centuries of the Holocene. For each of these sections, we present a δ18O anomaly curve and a common accumulation signal that represents regional changes in the accumulation rate over the Greenland ice cap.