A refraction seismic transect from the Faroe Islands to the Hatton-Rockall Basin

The crustal structure of the Faroe-Rockall Plateau was studied by a 790-km-long refraction seismic transect consisting of two intersecting lines. The air gun shot spacing was 200 m, and the signals were recorded by 77 ocean bottom seismometers. A P wave velocity model was developed from forward and inverse modeling of the wide-angle seismic data and incorporation of coincident multichannel reflection seismic data. Continental crust with velocities ranging from 5.6 to 6.8 km/s can be traced from the Faroe Islands, across the banks to the SW of the Faroes and into the Hatton-Rockall Basin. The thickness of the subvolcanic crust is up to 25 km on the banks but is as little as 8 km in the channels between the banks. The thinning in the channels may be related to NW-trending shear zones extending from major lineaments in NE Rockall Trough. Basalt layers are found along the entire transect with a total thickness of up to 4 km. Two layers with velocities of 4.9-5.2 and 5.3-5.6 km/s are thought to represent Paleogene flood basalts that can be correlated from the Faroe Islands to George Bligh Bank. Close to George Bligh Bank, an 80-km-wide and up to 9-km-thick body with velocities of 6.5 km/s is interpreted as intrusion. A 5-km-thick, high-velocity lower crustal layer (7.3 km/s) extends from the area of the intrusion into the northern Hatton-Rockall Basin. At the northern flank of Lousy Bank the transition zone to oceanic crust was encountered.