Extract

Three phases of Tertiary compressional deformation have been demonstrated in the Faeroe-Rockall Plateau (Boldreel & Andersen 1993). Compressional structures are mainly evident on the northern part of the Faeroe-Rockall Plateau and near the northern and western margins of the plateau (Fig. 1).

The first deformation phase followed extrusion of the Faeroe plateau basalts and affect the oldest of the sediments above the basalts. The age of these sediments is presumed to be earliest Eocene, and the authors believe this deformation phase followed immediately after the final break-up between the Faeroes and Greenland. The major ridges south of the Faeroe Islands (Wyville-Thomson, Ymir and Munkegrunnur) are evidence of this deformation phase. During this phase the Wyville-Thomson and Ymir Ridges formed as ramp anticlines on a north-dipping fault system (Boldreel & Andersen 1993). Renewed compression in the Oligocene was located in the same area, and these authors believe that during this phase inversion of the West Lewis Basin was linked to deformation of the Wyville-Thomson and Ymir Ridges (Earle et al. 1989). The latest and most widespread compression phase occurred in the Miocene. This resulted in the NW-SE trending compression structures along the continental margin north, west and southwest of the Faeroes. Evidence of this phase is also seen in the Faeroe-Shetland Channel.

It is likely that pre-existing structural elements controlled the actual location and orientation of some, if not all, of the structures we have observed. For instance, the proposed linkage between inversion of the West Lewis Basin and deformation of