Structure from the Faroes shelf to the Norwegian Basin

Extrusive basalt of up to 5 km thickness extends into the continental Faroes-Shetland Trough and a low-velocity zone (probably pre-basalt sediment) stretches beneath the basalt from the continental margin across the entire Faroes Shelf. Abnormally thick oceanic crust (up to 12 km) is found adjacent to the rifted continental margin, indicative of high temperatures caused by the Iceland mantle plume at the time of continental breakup. Clear seaward dipping reflectors are produced on the margin by extrusive lavas. Lower crustal intrusion is also inferred on the margin beneath the seaward dipping reflectors, from the high seismic velocities and layering observed in the lower crust.