Figure 6. Scheme showing vertical transects of hypothetical circulation geometry across the western and eastern Nordic Seas between North Atlantic, Greenland-Island (GI) / Island-Scotland (I-S) Ridge, and Fram Strait (schemes modified from Thornalley et al., 2015), showing deep- and intermediate-water convection separately for the eastern (lower panel) and western (upper panel) Nordic Seas. Grey arrow colors indicate brine water-induced intermediate waters and weak anti-estuarine overflow. Transect (A) for LGM, transect (B) for HS-1 times starting at 18.4 cal. ka. Red asterisks: Core sites PS2644 and 23074. Red numbers give prime evidence, the range of local planktic reservoir ages (MRA) and benthic ventilation ages. Pertinent MRA and bottom water ventilation ages for core sites RAPID-10-1P and RAPID-17-5P south of the Iceland-Scotland Ridge are from Thornalley et al. (2011). SSDW = Southern Source Deep Water, GA SSW = Glacial Atlantic Southern Source Waters, NIJ = North Iceland Jet, DSO = Denmark Strait Overflow, ISO = Iceland Strait Overflow, EGC = East Greenland Current. Estimates of full and partial sea ice cover for LGM and Heinrich transects are based on Sadatzki et al. (2019), and Sessford et al. (2019).
Note, in our view, MRAs and benthic ventilation ages listed by Thornalley et al. (2011 and 2015) and in part incorporated in Fig. 6B may not reflect true past values (1) because of a lack of precise atm. age calibration (leading to little evidenced MRAs), (2) since a majority of age samples were based on Pyrgo , etc. species which are strongly subject to the bias of ”old” pore waters in the ambient sediment (Magana et al., 2010).