​The relationship between hot spots and mantle plumes is still a topic of lively debate. We use the case of the Azores Triple Junction (ATJ) to address this unresolved problem and investigate the processes that can explain the chemical heterogeneity of extruded magmas at a regional scale. Our model of the Azores magmatism combines detailed geochemical data on silicate melt inclusions from samples collected across the ATJ with tectonics and high-resolution seismic images of the mantle. Carbonated-silicic melts metasomatization, related to the recycling of an old oceanic crust, and partial melting (3 to 5%) of a FOZO-type mantle can account for the overall geochemistry of the magmas extruded during the last 20 Ka. Melting occurred in the presence of water at a maximum pressure of 3.4 GPa and with a dmall difference of potential temperature from that one of the ambient mantle (∆T=1-98ºC). This weak thermal anomaly does not presently support the dominant influence of a thermal plume in the shallow mantle beneath the region. Lithosphere extension may have promoted decompression melting assisted by fluids, and deep faults enhanced the ascent of primitive magmas from their ponding zones.