Beneath the continental shelf north and west of Scotland, the upper crust consists of half-graben basins formed by extension and subsidence during the Devonian to Carboniferous and Permian to Jurassic periods. They developed on listric faults which dip southeastward and sole into a detachment surface previously used to emplace thrust sheets during the Caledonian orogeny, and subsequently used to invert the basins in the Tertiary.

West of the shelf is the deep Rockall Trough, which overlies a rift basin floored by intruded and very thin continental crust; this rift is a branch of the North Atlantic system, and extension began in the late Middle Jurassic. The rift continues northward and underlies the Faeroe-Shetland Channel, but is offset at the Orkney-Faeroe alignment, a cross-cutting tectonic element of early Paleozoic age or older.

Sediment distribution, thickness, and facies were strongly influenced by faulting, uplift, and subsidence. Regional paleorelief became lower with time, and prevailing conditions evolved from continental during the Devonian to marine during the Late Jurassic to Tertiary.