HR: 1340h
AN: PP33C-1606    [Abstracts]
TI: Annual Layering at 78 kyr BP in the NorthGRIP Ice Core
AU: * Svensson, A
EM: as@gfy.ku.dk
AF: University of Copenhagen, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen, 2100 Denmark
AU: Johnsen, S J
EM: sigfus@gfy.ku.dk
AF: University of Copenhagen, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen, 2100 Denmark
AU: Bigler, M
EM: bigler@gfy.ku.dk
AF: University of Copenhagen, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen, 2100 Denmark
AU: R�thlisberger, R
EM: rro@bas.ac.uk
AF: British Antarctic Survey, High Cross Madingley Road, Cambridge, CB3 OET United Kingdom
AU: Ruth, U
EM: uruth@awi-bremerhaven.de
AF: Alfred-Wegener-Institut f�r Polar und Meeresforschung, Columbusstra�e, Bremerhaven, 27568 Germany
AU: Bizet, B
EM: intiwasi@gfy.ku.dk
AF: University of Copenhagen, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen, 2100 Denmark
AU: Iversen, P
EM: pi@gfy.ku.dk
AF: University of Copenhagen, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen, 2100 Denmark
AB: Pronounced laminated layering is observed in the Visual Stratigraphy (VS) of the NorthGRIP ice core (75.1N; 42.3W) throughout the last glacial period. In the cold Greenland Isotopic Stadial 21 at around 2580 m depth, where the ice has an age of approximately 78 kyr, the layer thickness is estimated to be just below 1 cm. In order to verify that the observed layers are annual, we have carried out measurements of electrolytical conductivity and dust concentration at mm resolution in 2 meters of that ice. Together with the VS profile we apply those data to perform a dating, that results in a mean annual layer thickness of 0.8 cm, which is in good accordance with the modelled NorthGRIP time scale 'ss09sea'. This result makes us confident that the stratigraphic dating of the NorthGRIP ice core can be extended back to at least 80 kyr BP.
DE: 0724 Ice cores (4932)
DE: 1165 Sedimentary geochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005