Fig. 11.

Deep-water overturning circulation in the North Atlantic during modern interglacial, glacial, and Heinrich-event scenarios. Typical overturning patterns are shown in left panel, and corresponding map-view circulation patterns are sketched in the middle panel. Circles with bent arrows show areas of deep-water formation. Modified from Seidov and Maslin (1999). Semi-transparent white areas show previous LGM reconstructions of the Eurasian Ice Sheet and white curved arrows show major LGM palaeo-ice streams that drained the ice sheet (e.g., Bigg et al., 2012). In the bottom panel: tentative timeframe for the potential NwAC reductions in the Norwegian Sea inferred from the analysis of ploughmark trajectories and the global δ¹⁸O isotope curve as an ice volume proxy (from Lisiecki and Raymo, 2005).