Basement fault trends in the Southern North Sea Basin

Abstract

The Southern North Sea Basin (SNS) contains the regional Zechstein megahalite, a highly deformed Upper Permian salt layer, which partly obscures the Palaeozoic basement structures. This study provides a comprehensive and systematic analysis of pre-salt basement fault trends in the SNS mapped at the top Rotliegend level. We utilize a consistent fault mapping methodology with seismic attribute-based fault mapping techniques and GIS-based image tracing. The results are compared with published maps from the Southern North Sea area. Data analysis is performed on a supra-regional time-migrated 3D seismic dataset located offshore Netherlands and the United Kingdom. Statistical directional analysis of fault trends in the study area confirms the published dominant NW-SE basement trend and allows quantifying its contribution at approximately 51% of all fault segments. Basement fault trend distributions in individual sub-basins in the SW SNS are highly similar and show a strong NW-SE trend dominance despite different tectonic histories of those sub-basins. This may imply their joint origin prior to Caledonian accretion of the Laurussian continent. In the NE sub-basins, NE-SW, W-E and N–S trends are locally important and may represent the structural inheritance of smaller pre-Caledonian terranes.