The Greenland Ice Core Chronology 2005, 15-42 ka. Part 2: comparison to other records

Quaternary Science Reviews, Vol. 25, 23-24, doi:10.1016/j.quascirev.2006.08.003, 2006

A. Svensson, K.K. Andersen, M. Bigler, H.B. Clausen, D. Dahl-Jensen, S.J. Johnsen, S.O. Rasmussen, J.P. Steffensen and B.M. Vinther
Ice and Climate, The Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
S.M. Davies
Department of Geography, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UK.
R. Muscheler
NASA/Goddard Space Flight Center, Climate & Radiation Branch, Mail Code 613.2, Greenbelt, MD 20771, NASA/Goddard, USA.
R. Röthlisberger
British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK.

ABSTRACT.
A new Greenland Ice Core Chronology (GICC05) based on multi-parameter counting of annual layers has been obtained for the last 42 ka. Here we compare the glacial part of the new time scale, which is based entirely on records from the NorthGRIP ice core, to existing time scales and reference horizons covering the same period. These include the GRIP and NorthGRIP modelled time scales, the Meese- Sowers GISP2 counted time scale, the Shackleton-Fairbanks GRIP time scale (SFCP04) based on ¹⁴C calibration of a marine core, the Hulu Cave record, three volcanic reference horizons, and the Laschamp geomagnetic excursion event occurring around Greenland Interstadial 10. GICC05 is generally in good long-term agreement with the existing Greenland ice core chronologies and with the Hulu Cave record, but on shorter time scales there are significant discrepancies. Around the Last Glacial Maximum there is a more than 1 ka age difference between GICC05 and SFCP04 and a more than 0.5 ka discrepancy in the same direction between GICC05 and the age of a recently identified tephra layer in the NorthGRIP ice core. Both SFCP04 and the tephra age are based on ¹⁴C-dated marine cores and fixed marine reservoir ages. For the Laschamp event, GICC05 agrees with a recent independent dating within the uncertainties.