Figure 4. Comparison of various proxy records from sediment core PS2644
that document peak glacial-to-deglacial changes in surface and bottom
water oceanography at the northern entrance of the Denmark Strait 22 –
15 cal. ka (before 1950 AD). Age control based on 14C
plateau tuning technique. Top panel shows NGRIP δ18O
record of Greenland vs. cal. ka b2k (GICC05; Wolff et al., 2010) as
reference to coeval changes in northern hemisphere climate plotted vs.
planktic δ18O record of SST rise and meltwater
dilution of NIIC waters (Voelker, 1999). Roman numbers indicate time
segments I to IV. Panel 2 shows planktic reservoir ages (i.e., MRA; red
broken line), prominent changes in benthic ventilation age (blue line;
Sarnthein et al., 2020), and two separate populations of epibenthic
δ13C values obtained from single foraminifera tests
(Voelker, 1999). Panel 3 depicts epibenthic δ18O
values of single foraminifera tests (Voelker, 1999), where a 0.8 shift
in maximum δ18O reflects an abrupt 3.4°C rise in
minimum bottom water temperature near 18.4 cal. ka. Panel 4 shows
gradual rise in the radiogenic εNd portion of Nd
isotopes of authigenic and detrital sediment fractions as compared to
modern and mid-Holocene (”Oetzi time” ~5.7 cal. ka)
values (Kutschera, 2002). Panel 5 shows variations in authigenic and
detrital Pb206/Pb204 ratios. Panel 6 gives changes in bulk sedimentation
rate (cm/kyr) as derived from cal. ages obtained by means of the14C plateau tuning technique (Sarnthein et al., 2020).