Fig. 4: Meridional distribution of t_proj across the Drake Passage during the late, middle and early Holocene.

a–c, Meridional distribution of t_proj (years) across the Drake Passage during the late (a), middle (b) and early Holocene (c). Multiple age numbers along a single symbol indicate multiple samples from the same location during each period. The white lines in a illustrate the modern neutral density anomalies (GLODAPv2.2019; ref. ⁴⁹). Lighter background colour illustrates a younger ventilation age. The black dashed arrow indicates the inferred southward migration of the polar front (PF) in the early Holocene. The light blue area at the top of c denotes transiently enhanced mixing of the ¹⁴C-enriched signatures from the surface ocean in the early Holocene, probably associated with southward polar front migration and enhanced air–sea gas exchange.