Fig. 1: Bathymetric maps of the South Atlantic and Rio Grande rise.

a Bathymetric map of the South Atlantic Ocean. The continental surface expressions of the Paraná and Etendeka LIPs are outlined in red, filled gray. The Mid-Atlantic Ridge (MAR) is denoted by the center black dashed line and the Vema Trough (thought to be an extinct spreading center²) is marked by a dashed line west of RGR. The two arrows in WR indicate the two geochemical subtracks of the WR Guyot Province^18,19, with Tristan to the north and Gough to the south. Labeled yellow stars indicate the approximate locations of currently active hotspots. b Close-up bathymetric map of RGR with labeled dredge and drill (DSDP Hole 516 F) locations (diamonds and circle, respectively) and ages (in Ma). Red diamonds are dredge locations from cruise NBP1808 (this study) while three gray locations are from other campaigns that also produced ages^7,10,12. Eruption ages are shown in black font, eruption age estimations in grey, minimum eruption ages in blue, maximum eruption ages in red. All uncertainties are 2σ standard errors, stacked uncertainties are 97.5% (top) and 2.5% (bottom) confidence intervals using weighted kernel density estimations (WKDE). Dashed outlines show our distinction of sub-provinces: West (W-RGR), Northeast (NE-RGR), and Southeast RGR (SE-RGR) as individual sub-regions that are roughly separated by the Centaurus Basin (CB, hatched pattern). The Cruzeiro do Sul Rift (lined pattern) incises both W- and SE-RGR. Maps were created in GMT⁷⁰ and use GEBCO bathymetry⁷¹.