(Table S1) Age determination of sediment cores from the Labrador Sea

High resolution flow speed reconstructions of two core sites located on Gardar Drift in the northeast Atlantic Basin and Orphan Knoll in the northwest Atlantic Basin reveal a long-term decrease in flow speed of Northeast Atlantic Deep Water (NEADW) after 6,500 years. Benthic foraminiferal oxygen isotopes of sites currently bathed in NEADW show a 0.2per mil depletion after 6,500 years, shortly after the start of the development of a carbon isotope gradient between NEADW and Norwegian Sea Deep Water. We consider these changes in near-bottom flow vigor and benthic foraminiferal isotope records to mark a significant reorganization of the Holocene deep ocean circulation, and attribute the changes to a weakening of NEADW flow during the mid to late Holocene that allowed the shoaling of Lower Deep Water and deeper eastward advection of Labrador Sea Water into the northeast Atlantic Basin.

对位于东北大西洋盆地加达尔漂移沉积体（Gardar Drift）以及西北大西洋盆地孤儿海丘（Orphan Knoll）的两个岩芯位点开展的高分辨率流速重建研究显示，6500年之后东北大西洋深层水（Northeast Atlantic Deep Water, NEADW）的流速出现长期下降。当前处于NEADW影响范围内的岩芯位点的底栖有孔虫氧同位素（benthic foraminiferal oxygen isotopes）数据显示，6500年之后出现了0.2‰的同位素亏损，这一时间略晚于NEADW与挪威海深层水（Norwegian Sea Deep Water）之间开始形成碳同位素梯度的节点。我们认为，近底流活动强度以及底栖有孔虫同位素记录的这些变化，标志着全新世深海环流（Holocene deep ocean circulation）发生了重大重组，并将这些变化归因于全新世中晚期NEADW流的减弱：这一减弱使得下层深水（Lower Deep Water）发生浅化，并促使拉布拉多海海水（Labrador Sea Water）向更深层向东平流进入东北大西洋盆地。