Extended Data Fig. 6: Compositional overlap between modern Samoa (<5 Ma) and Cretaceous Samoan volcanoes—Hemler and Vlinder seamounts—in the West Pacific.

Most of the geochemical evolution of Samoan volcanoes through time is reflected in a drill core into Tutuila Island (Samoa⁴⁹). This shows (red arrow) a change in lava compositions from shield to rejuvenated lavas, with volcanoes active over the past 5 Ma¹¹⁴. The older samples^31,91 (ages shown in white text bubbles) from Hemler and Vlinder (~100 Ma) mainly plot around the shield lavas in Samoa while the youngest samples (~95 Ma) continue through the rejuvenated lavas represented by the most extreme EM1 type composition in the Samoan area (Uo Mamae¹¹⁹).