Paleoceanography of the Northwestern Greenland Sea and Return Atlantic Current evolution, 35–4 kyr BP.

The flow of the Atlantic Water (AW) via the Return Atlantic Current (RAC) regulates the oceanographical
conditions in the Northwestern (NW) Greenland Sea in the Fram Strait. As the intensity of the RAC might
significantly influence both deep-water formation in the area and the stability of the Northeast Greenland Ice
Sheet (NE GIS), knowledge of its variability in the past is important. Here we present a reconstruction of the
paleoceanographic forcing of the AW on climatic conditions and associated environmental changes in the NW
Greenland Sea by means of foraminiferal assemblages, stable (oxygen and carbon) isotopes, and various sedimentological parameters from sediment core GR02-GC retrieved from NE Greenland continental slope (1170 m
water depth). Our data indicate an almost continuous presence of AW in the NW Greenland Sea during the last 35
kyr BP. Two peaks of low planktic δ18O values at ~34.5 and 33 kyr BP are interpreted as meltwater signals
associated with warm AW-induced melting of the adjacent NE GIS. The NE GIS advanced between 32 and 29 kyr
BP, resulting in reduced meltwater influx to the NW Greenland Sea. Increased iceberg calving and melting after
29 kyr BP, were probably linked to surface warming and glacier advance to the shelf-break lasting until 23.5 kyr
BP. During the Last Glacial Maximum, the extensive sea ice cover was associated with the presence of subsurface
AW at the study site. During the Bølling–Allerød (B/A, ~14.6–12.7 kyr BP) strong melting of glaciers and sea ice
was probably caused by the combined effect of the B/A warming and the flow of warm AW. The RAC was
weakened during the Younger Dryas (~12.8–11.7 kyr BP), which reduced the advection of warm AW to the NW
Greenland Sea. After 11.7 kyr BP, the RAC reached its modern strength, whereas, during the Holocene Thermal
Maximum, it reached its maximum strength for the study period. In addition, short-term weakening of AW inflow
to the core site was observed, especially at 10.5, 8.5, and 5.8 kyr BP.