Deep water formation in the North Atlantic Ocean during the last ice age

Abstract

Oxygen-18 records of benthic foraminifera from northeastern Atlantic and Southern Ocean cores are significantly different. This difference indicates that the deep water in the northeastern Atlantic Ocean during the last Ice Age was at least 1.3 °C cooler than in modern times. We show here that the occurrence of such a cold deep water mass implies that the North Atlantic was a sink for dense surface waters, replacing the Norwegian Sea where ice cover and stratification prevented the formation of deep water.