Figure 3. North Atlantic palaeoceanographic proxy records from DSDP Sites 603 and 610, and IODP Sites U1308 and U1313 between 3.400 and 3.180 Ma.

Circles with white fill are data points from this study, circles with colour fill are from [30], [55] (C) and [26], [35] (D). Vertical grey bars represent glacials, white bars are interglacials. (A) palaeomagnetic reversals; (B) benthic isotope age models for each site tuned to the LR04 stack [10] (black line), thin coloured lines are data, thick coloured line is 4-point running mean; (C) alkenone SSTs (0–10 m water depth) including calibration related error (shading), horizontal lines represent modern average annual temperature at 0–50 m water depth for each site; (D) SSTs at 0–60 m water depth based on Mg/Ca of G. bulloides, including a 1°C error bar (shading), horizontal lines represent modern average spring (March-April-May) temperature at 0–50 m water depth for each site; (E) SWT_Mg/Ca of G. inflata at 300–400 m water depth; (F) calculated δ¹⁸O_sw-ice as estimate of salinity; thick coloured lines are a 4-point running mean; (G–J) dinoflagellate cyst assemblage composition. High abundances of O. centrocarpum (yellow) indicate an active NAC. Bluish colours  =  cool-water species, reddish colours  =  warm-water species; (G) and (H) contain data presented in [26] and [35]. (J) B. tepikiense and F. filifera are grouped together at DSDP Site 603 and are represented by the colour for B. tepikiense (purple); Impagidinium cf. pallidum is represented as Impagidinium pallidum.