Changes in sea surface hydrology associated with Heinrich event 4 in the North Atlantic Ocean between 40° and 60°N

The changes in distribution of sea surface temperature and salinity in the North Atlantic between 40 and 60°N were reconstructed for the time interval between 40 and 30 kyr BP, which includes the large iceberg discharge event associated with the deposition of Heinrich layer 4. We found that the meltwater input during deposition of Heinrich layer 4 resulted in a 1–2 kyr temperature decrease of about 2°C and a salinity decrease in the range of 1.5‰–3.5‰ between 40 and 50°N. Sites above 50°N did not experience significant salinity variations. A much larger area was affected by the reduction in sea surface temperature. The amplitude of the sea surface temperature shift was, however, much smaller than the atmospheric temperature changes over Greenland at GISP and GRIP sites.