Coherent deep flow variation in the Iceland and American basins during the last interglacial

The first direct evidence that the deep flow speed of North Atlantic Deep Water (NADW) in the South Iceland and North American Basins declined dramatically over a period of a few hundred years at about 120,000 years ago is presented. The flow rate inferred from silt grain-size then rose into the subsequent cool period (stage 5d). These changes are clear and synchronous in records from both locations. These circulation events are recorded less markedly in chemical and isotopic proxies for the nutrient status of water masses. The congruence of flow variation and hydrography at the two separated sites suggests they are primarily controlled by variation in the deep thermohaline circulation.