The Cretaceous of Scotland consists of a succession of sedimentary rocks that record episodic marine transgression, from both east (North Sea) and west (Atlantic), over the eroded rift terrains of Late Cimmerian tectonism. In common with much of NW Europe and the Atlantic borders of Canada and Ireland, the Early Cretaceous was dominated by clastic deposition in a moderately active tectonic regime (Sinclair et al. 1994). Passive subsidence was the dominant process in the Late Cretaceous, accompanied by carbonate and hemipelagic deposition (Hancock & Rawson 1992). The Chalk Group sediments are considered to have once covered much of what is now the Scottish mainland, only to have been removed during the Tertiary-Quaternary uplift, accompanying the opening of the North Atlantic Ocean.
The dominant NE-SW structural trend for the half graben systems to the west of Scotland, shows reactivation of old Caledonian lineaments, parallel to the Moine Thrust (Fig. 12.1). This area represents the SE rifted margin of the Proto North Atlantic, across from the eastern seaboard of North America and Greenland (Ziegler 1988a). Atlantic rifting was rejuvenated through the Tertiary, as evidenced by extensive igneous activity (Stoker et al. 1993; Fyfe et al. 1993). The Faeroe escarpment marks the southern limit of the widespread Tertiary plateau basalts that mask the underlying Cretaceous stratigraphy to the NW of Scotland. Cretaceous North Sea rifting was inherited from the Late Cimmerian (Jurassic) tectonism that produced the triple junction of the NNE-SSW Viking, the WNW-ESE Moray Firth and the NW-SE Central graben