Abstract

Sediment cores from the Nordic (Greenland, Iceland, and Norwegian) seas provide evidence that this area acts as an initial responder to the forcing effect of orbitally driven changes in insolation on the climate system, as postulated by J. Imbrie et al. The δ18O record of the cores documents a widespread initial deglacial signal in the area between 15 and 13 ka, ∼1000 yr before other deglacial signals from other parts of the Northern Hemisphere. An even earlier meltwater event has been dated to 16,090 ±185 yr B.P. north of Iceland, at the initial rise of Northern Hemisphere insolation after the last glacial maximum. During the period with lowered surface salinities, the Nordic seas were still cold. Reconstructions of the surface-water conditions of the area show that, as the summer insolation values of the Northern Hemisphere reached half of maximum values, a sea-ice-free corridor opened along Norway at ∼13.4 ka. Nearly contemporaneous fluctuations of the polar front and the sea-surface temperatures with the insolation changes indicate that the Nordic seas are very sensitive to insolation forcing, especially in regions close to the sea-ice margin. A decrease in sea-surface temperature and an increase in the areal extent of sea-ice cover since 7 ka indicate that the area is currently on the way to glacial conditions, supporting the predictions made earlier by J. Imbrie et al.

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