Fig. 3. Profiles and meridional sections of proxies for deep ocean circulation.

The δ¹⁸O profile (A) uses Cibicidoides spp. (circles) and Uvigerina spp. (squares), with Uvigerina data corrected for vital effects by –0.47‰ (160); the δ¹³C profile (B) uses Cibicidoides spp. only; profile data are from the NW Pacific (6). LGM δ¹³C data (in B and D) and δ¹⁸O are corrected for the –0.34 and 1‰ whole ocean changes in δ¹³C and δ¹⁸O_sw (17). Generalized additive model fits are shown for Holocene δ¹³C and δ¹⁸O (dashed lines) and LGM δ¹³C (solid line) (161). The thin dotted-dashed line through the LGM δ¹⁸O data in (A) is the Holocene δ¹⁸O fit with a +0.6 ‰ offset; while the Holocene δ¹⁸O profile increases smoothly with depth, the LGM data exhibit a marked transition at ~2000 m, indicative of a water mass boundary. ¹⁴C data in (C) are shown as ¹⁴C age relative to the contemporaneous atmosphere, with modern data from GLODAPv2 and LGM data from benthic foraminfera (see Materials and Methods for details). δ¹³C section data in (D) are from the western Pacific (17)—see inset map. Locations of sediment core data are shown in black dots and areas of poor data coverage in white, and further details are given in figs. S2 and S3.