Conversion of GISP2-based sediment core age models to the GICC05 extended chronology

•Portions of the NGRIP GICC05 and GISP2 M/S94 chronologies exhibit offsets exceeding 4000 years.•A Matlab/Octave or Python script converts M/S94-based sediment core age models to GICC05.•The script incorporates all available volcanic match points synchronizing GISP2 and NGRIP.•Modular design allows future inclusion of forthcoming, extensive volcanic synchronization.•Converted paleo proxy data exhibit improved temporal agreement to absolutely-dated speleothems.

Marine and lacustrine sediment-based paleoclimate records are often not comparable within the early to middle portion of the last glacial cycle. This is due in part to significant revisions over the past 15 years to the Greenland ice core chronologies commonly used to assign ages outside of the range of radiocarbon dating. Therefore, creation of a compatible chronology is required prior to analysis of the spatial and temporal nature of climate variability at multiple locations. Here we present an automated mathematical function that updates GISP2-based chronologies to the newer, NGRIP GICC05 age scale between 8.24 and 103.74 ka b2k. The script uses, to the extent currently available, climate-independent volcanic synchronization of these two ice cores, supplemented by oxygen isotope alignment. The modular design of the script allows substitution for a more comprehensive volcanic matching, once it becomes available. Usage of this function highlights on the GICC05 chronology, for the first time for the entire last glaciation, the proposed global climate relationships during the series of large and rapid millennial stadial-interstadial events.