Extended Data Figure 2: Seafloor and radiocarbon distributions of the whole Pacific and the southeastern Pacific.

The whole Pacific (shown in a–c) comprises the main Pacific (shown in Fig. 3) and the southeastern Pacific (shown in d–f) domains defined in Extended Data Fig. 1b. a, d, Zonally summed seafloor areas as a function of latitude and depth. b, e, Zonally summed incrop areas as a function of latitude and pseudo-depth. c, f, Along-density zonal mean radiocarbon content (Δ¹⁴C) as a function of latitude and pseudo-depth. Panels with a pseudo-depth y axis have density contoured in black every 0.1 kg m⁻³ for γ ≥ 27.5 kg m⁻³. White curves depict the local northward–southward and diabatic–adiabatic transition levels inferred from the incrop area distribution, as in Fig. 3. The cluster of large incrop areas within 28–28.06 kg m⁻³ south of 20° N seen in b originates in the southeastern Pacific, which hosts a secondary circulation branch^71,72 separate from the main abyssal overturning cell (Methods).