Fig. 6: Backtracked locations of RGR and WR volcanism.

a Rotated to the modern ridge using half-stage rotation parameters of Pérez-Díaz & Eagles⁴¹. b Four different absolute plate motion models, which show the location of T-G plume volcanism relative to the modern ridge, and a general southward motion of the plume through time. Absolute plate motion models used: 1 = mantle reference frame⁴⁹, 2 = moving hotspots model⁴⁸, 3 = moving hotspots model⁵⁰, 4 = global hybrid model⁵⁰. WR ages come from the same references as those in Fig. 3. Colors correspond to the age of each sample. The MAR is the thick black line in the middle of each panel, fracture zones are grey lines with two important fracture zones highlighted in magenta in panel (a): PFZ Peleg Fracture Zone, RFZ Rachel Fracture Zone. The dotted portions of these extend into the regions of the RGR and WR where they are overprinted by volcanism. The blue circle in (a) shows the bifurcation point of WR, note that this occurs exactly where the PFZ intersects WR. W-RGR late-stage Eocene volcanism is circled in orange. Other off and near-axis volcanism during the formation of W-RGR and late stages of NE-RGR is circled in grey in panel (a). The green arrow in (a) shows the apparent westward shift in WR volcanism at PFZ and the shift to the African Plate only south of the RFZ. The dotted black box in (a) outlines the areas in panel b. Each map was made in GMT⁷⁰.