Evidence for a steeper Eemian than Holocene sea surface temperature gradient between Arctic and sub-Arctic regions

Sediment proxy data from the Norwegian, Greenland, and Iceland seas (Nordic seas) are presented to evaluate surface water temperature (SST) difference s between Holocene and Eemian times and to deduce from these data the parti cular mode of surface water circulation. Records from planktic foraminifera l assemblages, CaCO3 content, oxygen isotopes of foraminifera, and iceberg- rafted debris form the main basis of interpretation. All results indicate f or the Eemian comparatively cooler northern Nordic seas than for the Holoce ne due to a reduction in the northwardly flow of Atlantic surface water tow ards Fram Strait and the Arctic Ocean. Therefore, the cold polar water flow from the Arctic Ocean was less influencial in the southwestern Nordic seas during this time. As can be further deduced from the Eemian data, slightly higher Eemian SSTs are interpreted for the western Iceland Sea compared to the Norwegian Sea (ca. south of 70 degrees N). This Eemian situation is in contrast to the Holocene when the main mass of warmest Atlantic surface wa ter hows along the Norwegian continental margin northwards and into the Arc tic Ocean. Thus, a moderate northwardly decrease in SST is observed in the eastern Nordic seas for this time, causing a meridional transfer in ocean h eat. Due to this distribution in SSTs the Holocene is dominated by a meridi onal circulation pattern. The interpretation of the Eemian data imply a dom inantly zonal surface water circulation with a steep meridional gradient in SSTs. (C) 1999 Elsevier Science B.V. All rights reserved.