This dataset represents the structure and topography of the Top Chalk surface, i.e. the top of the Chalk Group (including Upper Cretaceous to Danian), in the Danish subsurface. The map illustrates regional variations in the depth and structural configuration of the chalk surface from the central North Sea to the eastern Danish areas. It is based on an integrated geological and geophysical interpretation of seismic profiles, well data and earlier mapping. The map provides an essential basis for geological, geophysical and subsurface reservoir analyses.

The dataset comprises a geological structural map of the Danish Basin at a scale of 1:500,000 showing the structure of the chalk surface (Top Chalk). The map was published in 1991 as part of the DGU Map Series no. 7 and is based on regional geological interpretation of borehole data and seismic data. The data basis includes deep onshore boreholes, seismic profiles from hydrocarbon exploration, and seismic surveys from the inner Danish waters. The map covers Denmark and adjacent marine areas and was produced to support regional geological understanding of the structure of the chalk surface in the Danish Basin.

The dataset comprises a geological map of the Danish Central Graben at a scale of 1:200,000 presenting regional maps of ‘Top Chalk’ and the Post-Chalk Group in terms of two-way travel time, depth and interval velocity. The map was published in 1995 as part of the DGU Map Series no. 47 and was produced as part of a comprehensive geological mapping of the Danish Central Graben. The mapping is based on interpretation of seismic data supplemented by information from boreholes. The map covers the Danish part of the Central Graben and parts of the eastern North Sea block, and adjacent areas in the Norwegian, British and German sectors are included where data were available in order to define regional structural relationships. The map sheet comprises several thematic sub-maps that together describe regional variations in structure and stratigraphy.