Cenozoic development of the Norwegian margin 60–64°N: sequences and sedimentary response to variable basin physiography and tectonic setting

Abstract

The Cenozoic development of the Norwegian margin between 60 and 64°N can be described in terms of five, unconformity-bounded, megasequences: Paleocene–lowermost Eocene (65–51 Ma), Lower Eocene–lowermost Oligocene (51–31 Ma), Lower–upper Oligocene (31–24 Ma), Miocene–Pliocene (24–1.9 Ma), and Pleistocene (1.9 Ma–present). Each sequence is constructed of systems tracts, varying in type and number between sequences. In the Møre Basin (62–64°N), lowstand wedges dominate and form an offlapping, regressive pattern. In the Northern North Sea Basin (60–62°N), lowstand, transgressive and highstand systems tracts are present, showing a more variable framework. The variability observed is interpreted to reflect the response of sediment supplied, both in time and space, into different basin physiographies related to the overall tectonic context of the two areas. The Northern North Sea Basin in the Cenozoic received sediments generated from the basin margins in periods of uplift and lowstand. Clastic systems probably prograded into a gradually-shallowing central basin area, formed as a response to decaying, post-rift subsidence, margin uplift and sediment fill. The Møre Basin, in contrast, acted as a margin to incipient and on-going North Atlantic rifting, and the basin physiography was that of a more steeply inclined slope facing the northwest. Larger water depths caused sediment wedges to be restricted to the basin margin rather than acting as fill of the central basin area such as occurs in the North Sea. The offlapping pattern probably records repeated uplift of the Norwegian mainland, shedding sediments into the basin.