Abstract As part of the Norwegian Deep Water Programme, a regional geological and geophysical interpretation of the mid-Norwegian margin resulted in the establishment of a late Paleogene to Holocene stratigraphic framework for the margin, and identification and mapping of a range of possible geohazards, including slides. At the Vøring margin in the north, there has been the build-out of a huge prograding wedge of sediment in Plio-Pleistocene times. The sediments of the wedge are assigned to the Naust Formation, which has been subdivided into eight units (A-H), and includes only a few palaeoslides. To the south of the Vøring margin lies the Storegga Slide Complex and the North Sea Fan, and the whole of this southern region shows evidence of several major palaeoslides. The sediments are also referred to the Naust Formation, which here are subdivided into nine units (O-W) that have been partly correlated with equivalent Naust units to the north. The oldest Naust unit in the south, Naust Unit W, is largely made up of slide deposits that provide evidence for the earliest identified large-scale slope instability in the Storegga Slide Complex. This instability was penecontemporaneous with the initiation of the prograding wedge to the north, and both features are postulated to be the result of uplift of the Norwegian mainland. In the case of the Storegga Slide Complex, which lies close to the main area of uplift, oversteepening of the margin, together with seismicity associated with the Jan Mayen Fracture Zone and Møre-Trønderlag Fault Complex, may have initiated sliding that has since occurred intermittently up to Holocene times, over a time interval when there has additionally been much glacio-isostatic movement.

Abstract A Middle to Late Miocene compression phase has been documented along the Norwegian margin from 62°N to 68°N. Reverse faults and inversion domes are numerous on the 300 to 450 km wide central mid-Norwegian margin, but are only locally observed on the Møre and Lofoten margins. A major regression forced the coastline of the syn-tectonic Kai Formation 50–150 km west of the present coastline and a genetic link between the regression and the smaller-scale contraction structures is observed. Long wavelength (200–300 km) lithospheric bulging is suggested to explain the coastline regression at the onset of the compression phase. The position of the regressed coastline suggests that the continent -shelf transition guides the lithospheric buckling such that the thicker crust segment is uplifted. Long wavelength folding may account for additional crustal shortening along the sharp crustal transitions on the Lofoten and Møre margins. It is suggested that the Norwegian onshore domes were formed during at least two independent stages – a Middle to late Miocene compression-related uplift and later regional glacial isostatic uplift. The syn-tectonic Kai Formation fills in the depressions around the contraction-related structures and is dated as late Middle to Late Miocene. It is suggested that both the Utsira Formation and the assumed northern equivalent, the Molo Formation, were deposited after the compression event and, thus, are mainly early Pliocene in age. The Middle to Late Miocene compression phase is observed throughout the North Atlantic and the sea-level fall at the initiation and rise at the termination corresponds with significant shifts in climate.