The extrusive volcanic complex in the northeast Atlantic is characterized by the presence of SDR along the majority of the rifted margin segments, while numerous other volcanic seismic facies units are also regionally mappable. Available drill holes show the presence of extensive subaerially emplaced basaltic constructions, but the well sites have a strong bias toward sampling the Landward Flows and the inner part of the SDR. Many second-order features are still poorly constrained by the existing database. The drilling has not yet been able to confidently resolve important scientific questions regarding the nature of the intrabasalt reflectivity, the eruption and emplacement environment of the bulk part of the extrusive complex, and the relative importance of tectonic and magmatic processes during construction of the volcanic piles (Table 2). The significant asymmetry of the volcanic complexes revealed by studies of conjugate margin transects suggests that tectonic control may initially play an important role during the construction of the extrusive volcanic sequences. Both improved seismic and borehole data and improved models are required to resolve important scientific questions related to volcanic margin formation.