HR: 10:20h
AN: PP31D-01 INVITED     [PDF]
TI: The Eem Interglacial Strata in the Deep Greenland ice Cores. New Compelling Evidence From the NorthGRIP ice Core for the 5e/5d Transition.
AU: * Johnsen, S J
EM: sigfus@gfy.ku.dk
AF: Niels Bohr Institute, Department of Geophysics, Juliane Maries Vej 30, Copenhagen, DK-2100 Denmark
AU: Dahl-Jensen, D
AF: Niels Bohr Institute, Department of Geophysics, Juliane Maries Vej 30, Copenhagen, DK-2100 Denmark
AU: Steffensen, J P
AF: Niels Bohr Institute, Department of Geophysics, Juliane Maries Vej 30, Copenhagen, DK-2100 Denmark
AU: Clausen, H B
AF: Niels Bohr Institute, Department of Geophysics, Juliane Maries Vej 30, Copenhagen, DK-2100 Denmark
AU: Jouzel, J
AF: LSCE UMR CEA/CNRS 1572 Bat 709, L'Orme des Merisiers CEA Saclay, Gif s/ Yvette, F-91191 France
AU: White, J
AF: Institute of Arctic and Alpine Research, University of Colorado, Boulder 1560 30th St., Boulder, Co 80309-0450 United States
AU: Sveinbjornsdottir, A E
AF: Science Institute, University of Iceland, Dunhaga 3, Reykjavik, IS-107 Iceland
AU: Masson-Delmotte, V
AF: LSCE UMR CEA/CNRS 1572 Bat 709, L'Orme des Merisiers CEA Saclay, Gif s/ Yvette, F-91191 France
AU: Miller, H
AF: Alfred Wegener Institute, Columbusstrasse, Bremerhaven, D-27515 Germany
AU: Fujii, Y
AF: National Institute of Polar Research, 9-10, Kaga 1-Chome Itabashi-ku, Tokyo, 173 Japan
AB: While most Antarctic deep ice cores have Eem strata with high stratification integrity, Eem strata found in most Greenland deep ice cores show disrupted layering. In contrast, the order of magnitude higher accumulation rates in Greenland move these layers close to bedrock where they can be badly disrupted by ice flow over bedrock undulations. A perfect example is found in the GRIP and GISP2 ice cores. The isotope profiles are almost identical back to MIS 5c and uncorrelated below the onset of 5c. In this near bottom ice several layers with 3 per mille higher oxygen isotope ratios are found in both cores pointing to ice of warm Eem origin. In other deep cores like Camp Century, Renland and Dye-3, Eemian like ice is found in the very lowest strata boosting 4 to 5 per mille higher oxygen isotope ratios than the corresponding present day values. This implies that there was ample ice in NW Greenland and on South Dome during the Eem interglacial. The NorthGRIP core has suffered strong bottom melting due to high geothermal heat fluxes south of the drill site. This has, combined with the flat bedrock, helped to preserve the stratification all the way to bedrock while estimated 7 ka of the early Eem strata together with all older ice has been melted away. The warmest and deepest ice from the NorthGRIP Eem has the same isotopic values as the GRIP and GISP2 layers that we have assigned to the Eem period. Correlation with the planktonic isotopes of the Iberian margin core MD95-2042 for the Eem/last glacial transition shows that known cold pollen events like Montaigue and Melisey I make a definit imprint on the NorthGRIP isotope profile. A new Greenland isotope interstadial IS25 is found at the very end of the Eem interglacial.
DE: 1620 Climate dynamics (3309)
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 3309 Climatology (1620)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting