Variation in surface and deep water circulation in the Denmark Strait, North Atlantic, during marine isotope stages 3 and 2

Abstract

The paleoceanography in the Denmark Strait, North Atlantic, is reconstructed based on down core analysis of planktonic foraminifera, carbon and oxygen isotopes, carbonate, and ice rafted debris (IRD). The stratigraphy spans 57 to 6 calibrated (cal) ka years and reveals sea surface temperatures that covary with Greenland ice core temperatures throughout marine isotope stages (MIS) 3 and 2. Planktonic δ18O minima, interpreted as meltwater events, follow sea surface warming. IRD from both the Greenland and Iceland Ice Sheets was delayed by ∼2 ka relative to the North Atlantic Heinrich events. Ventilation of bottom water was mostly sustained through open ocean convection associated with North Atlantic Deep Water production or by convection of glacial North Atlantic Intermediate Water, except for two episodes at ∼54 cal ka (MIS 3.31) and 18–15 cal ka (termination I). During these two periods we suggest that deep water ventilation was accomplished mainly by brine formation.