Structural analysis and measured extension in fault complexes along the Lofoten‐Vesterålen margin, offshore Norway, in the context of crustal‐scale rifting towards breakup in NE Atlantic

Abstract

Late Cretaceous-Palaeocene continental extension within the Lofoten-Vesterålen margin is investigated by integrating 2D-3D seismic and potential field datasets, together with updated crustal transects. Most of that deformation is recorded by two low-angle detachment structures named West Røst High Fault Complex (WRHFC) and North Utrøst Ridge Fault Complex (NURFC) located at the southern and central-northern portions of the studied area, respectively. Multiple extensional episodes of various intensities were mapped as different fault stages, including one Albian-Cenomanian phase, four early Late Cretaceous phases, three Late Cretaceous to latest Cretaceous-Palaeocene phases, and one Palaeocene phase. The WRHFC is narrower in extent and has accommodated a relatively greater amount of localized extension (ca. 18-19 km), whereas the NURFC occupies a wider area with widespread extension intensity (ca. 6-8 km). In comparison, the total acrossmargin average extension within the southern, central, and northern portions of the Lofoten-Vesterålen and NE Greenland conjugate margins are ca. 192, 221, and 266 km, respectively. Such results indicate an apparent extension discrepancy between derived extension from measured fault-block geometries within the fault complexes and the whole conjugate margin system, with only ca.