The Evolution of Central Volcanoes in Ultraslow Rift Systems: Constraints From D. João de Castro Seamount, Azores

The Dom João de Castro seamount in the Hirondelle Basin (Azores) is a central volcano on ultraslow diverging Terceira Rift axis. combination of structural and geochemical data provides insights into evolution volcanoes oceanic rift systems above Azores melting anomaly. orientation fault scarps volcanic structures at D. adjacent fissure zone indicate that regional SW-NE extending stress field dominates morphology NW Basin. tectonic controls crustal melt pathways leads to dike emplacement along zones prevalent eruption mafic lavas. occurrence felsic lavas gives evidence for both deep shallow reservoir generating subordinate local seamount. New Sr-Nd-Pb isotope with incompatible trace element ratios Ridges originated from similarly heterogeneous mantle source but did not form simultaneously. Our new model implies by growth ridges transitioned circular edifices after magmatic generate changes lithospheric field. geometry other combined alkaline nature erupted lavas, large lithosphere thickness indicates young rifts are more similar continental rather than mid-ocean ridges.