Chronology for the East GReenland Ice-core Project (EGRIP)

This paper provides the first chronology for the deep ice core from the East GReenland Ice-core Project (EGRIP) over the Holocene and late last glacial period. We rely mainly on volcanic events and common patterns of peaks in dielectric profiling (DEP), electrical conductivity measurements (ECM) and tephra records for the synchronization between the EGRIP, NEEM and NGRIP ice cores in Greenland. We transfer the annual-layer-counted Greenland Ice Core Chronology 2005 (GICC05) timescale from the NGRIP core to the EGRIP ice core by means of 373 match points. The NEEM ice core is only used for supporting match-point identification. We name our EGRIP time scale GICC05-EGRIP-1. Over the uppermost 1383.84 m, we establish a depth–age relationship dating back to 14,965 a b2k (years before the year 2000 CE). Tephra horizons provide an independent validation of our match points. In addition, we compare the ratio of annual layer thicknesses between ice cores in-between the match points to assess our results in view of the different ice-flow patterns and accumulation regimes of the different periods and geographical regions. This initial timescale is the basis of interpretation and refinement of the presently derived EGRIP high-resolution data sets of chemical impurities.