(a) Sketch on the time-related evolution of magmatism at São Jorge. The shaded area at the base of the figure represent the melting zones from São João to Manadas (i.e. 1.3 Ma to Holocene). Melting would start at about 110 km depth and stop at ca. 80 km (vertical axis not to scale). São João magmas (ca. 1.3 Ma) from the eastern part of the island (São João section) derive from a mantle source dominated by a low-Δ7/4 signature. Coeval lavas (1.3 Ma) from slightly further west, i.e. from the Lower Vimes section, are generally dominated by the HIMU-type component as are the few analysed lavas from the ca. 0.7 Ma Serra do Topo V.C. (Middle Vimes). Lavas belonging to the ca. 0.4–0.1 Ma Rosais V.C. are dominated by the EM-2 component in the west (João Dias section) and by the HIMU-type component in the east (Upper Vimes). Finally, Manadas lavas have a prevailing HIMU-type signature. The crustal and lithospheric mantle depths are reported after Ferreira et al. (2020), Spieker et al. (2018), and Zanon et al. (2023). (b) The dominant mantle compositions for the Central Azores OIBs. The shaded field to the South-East of SãoJorge shows the geographic distribution of basalts with compositions similar to those from the São João V.C. (São João and Lower Vimes sections, ca. 1.3 Ma) and includes early basalts from Terceira (ca. 0.4 Ma) and Faial (ca. 0.8 Ma; Hildenbrand et al., 2014) and lavas from Pico (<0.21 Ma; Béguelin et al., 2017, and references therein). Basalts and intrusive rocks with an EM-type signature are represented by the shaded field to the North-West of São Jorge and include basalts from Faial and São Jorge (Rosais V.C., north-western cliffs of the island), both ca. 0.4–0.2 Ma (this study and Hildenbrand et al., 2014), and some magmatic rocks from Graciosa (Larrea et al., 2014). HIMU-type basalts have been found in all Central AZ islands, with the possible exception of Faial and span in age from 1.3 Ma to Holocene. The isotopic compositions of the Eastern AZ (Beier et al., 2007, 2018; Elliott et al., 2007; Béguelin et al., 2017) is partially different from those of the Central AZ as has been described in the text. (c) Panel is modified after Yang et al. (2006) and shows tomographic evidence for the presence of two distinct branches of the AZ plume, one branch rising under the Central AZ, the other one rising towards São Miguel in the Eastern AZ.