The Quaternary geology in the eastern part of the North Sea is characterized by large-scale
glaciotectonic complexes. The northernmost complex is the Jammerbugt Glaciotectonic Complex here addressed,
which occupies an area of more than 300km2. It was recently recognized during an investigation of conventional
seismic profiles located about 10km offshore the west coast of northern Denmark. The deformed bedrock includes
the main part of the Cretaceous Chalk Group in the North Sea. In the northern part of the complex the detachment
surface is situated in Lower Cretaceous greensand about 400m below sea level. In the central part of the complex,
the thrusting ramps the strong reflectors at the base of the Chalk Group and the detachment surface continues in
the lower part of the Upper Cretaceous chalk. In the tectonic depression north of the complex, marine and
glaciomarine deposits represent the Eemian–Early Weichselian Skærumhede Group, indicating a Saalian age of the
glaciotectonic deformation. The balancing of the thrust fault structures shows that the thrust sheets in the tailing
end of the complex had their source in the Skagerrak sea. The hole caused by displacement contributed to
formation of the Skagerrak depression, i.e. early stage of the Norwegian Trench.