North Sea Basin

This paper links research questions in Quaternary geology with those in Palaeolithic archaeology. A detailed geological reconstruction of The Netherland’s SW offshore area provides a stratigraphical context for archaeological and palaeontological finds. Progressive environmental developments have left a strong imprint on the area’s Palaeolithic record. We highlight aspects of landscape evolution and related taphonomical changes, visualised in maps for critical periods of the Pleistocene in the wider southern North Sea region. The Middle Pleistocene record is divided in two palaeogeographical stages: the pre-Anglian/Elsterian situation with a wide land bridge between England and Belgium even during marine highstands; and the Anglian/Elsterian to Saalian interglacial situation with a narrower landbridge, lowered by proglacial erosion but not yet fully eroded. The Late Pleistocene situation is very different, with the landbridge fully dissected by an axial Rhine-Thames valley, eroded deep enough to fully connect the English Channel and the North Sea during highstands. This tripartite staging implies great differences in (i) possible migration routes of herds of herbivores as well as hominins preying upon them, (ii) the erosion base of axial and tributary rivers causing an increase in the availability of flint raw materials and (iii) conditions for loess accumulation in Northern France and Belgium and the resulting preservation of Middle Palaeolithic sites.

Many rift zones exhibit a range of fault orientations, rather than simple colinear faults that strike orthogonal to the inferred least principal stress. The formation of non-colinear fault sets has implications for assessing rift-zone kinematics, as well as determining palaeo-stress state in extensional basins. Using 3D seismic reflection data, we deduce the likely mechanisms responsible for the formation of a population of non-colinear faults in the Måløy Slope area of the northern North Sea. Three basement-displacing fault populations exist on the Måløy Slope; (i) large (>1 km throw), N-S-striking faults, (ii) smaller (<250 m throw) N-S-striking faults and (iii) small (<250m throw) NE-SW-striking faults. All were initiated in the Middle Jurassic. Coeval growth of these fault populations, and the apparent correlation between the NE-SW faults and a NE-SW-trending gravity and magnetic anomaly high lead us to suggest that the NE-SW faults are the result of deflection of the otherwise E-W-orientated least principal stress by NE-trending intrabasement weaknesses. Our study’s results have implications for the large-scale kinematic evolution of the North Sea, arguing that major rotations in extension direction are not required to generate multiple fault sets locally or across the rift. This study also highlights the importance of using borehole-constrained 3D seismic data as a tool in understanding non-colinear fault growth, and its broader implications for regional tectonic history.