Duration of Greenland Stadial 22 and ice-gas Δage from counting of annual layers in Greenland NGRIP ice core ...

• Main Authors: Bigler, M., Blunier, T., Warming, E., Rasmussen, S. O., Popp, T. J., Kjær, H. A., Steffensen, J. P., Svensson, A. S., Stowasser, C., Kipfstuhl, S., Winstrup, M., Bertagna, G., Vallelonga, P.
• Format: Text
• Language: English
• Published: Copernicus Publications 2012
• Subjects: Antarc*; Antarctic; Greenland; Greenland ice core; ice core; NGRIP
• Online Access: https://dx.doi.org/10.7892/boris.18153; http://boris.unibe.ch/18153/

High-resolution measurements of chemical impurities and methane concentrations in Greenland ice core samples from the early glacial period allow the extension of annual-layer counted chronologies and the improvement of gas age-ice age difference (Δage) essential to the synchronization of ice core records. We report high-resolution measurements of a 50 m section of the NorthGRIP ice core and corresponding annual layer thicknesses in order to constrain the duration of the Greenland Stadial 22 (GS-22) between Greenland Interstadials (GIs) 21 and 22, for which inconsistent durations and ages have been reported from Greenland and Antarctic ice core records as well as European speleothems. Depending on the chronology used, GS-22 occurred between approximately 89 (end of GI-22) and 83 kyr b2k (onset of GI-21). From annual layer counting, we find that GS-22 lasted between 2696 and 3092 years and was followed by a GI-21 pre-cursor event lasting between 331 and 369 yr. Our layer-based counting agrees with the duration ...