GEUS has carried out a geological screening of the entire Danish sea area for the Danish Energy Agency with a view to establishing a better geological data basis for offshore wind development. The purpose of the project is to achieve greater certainty that a given area, in future designations of offshore wind areas, is geologically suitable for offshore wind. The results from the project, together with a sensitivity mapping of natural and environmental parameters, initiated by the Danish Energy Agency, will be included in an overall assessment of suitable areas for offshore wind in Denmark.

Through an overall geological mapping of the entire Danish sea area, a comprehensive understanding of the near-surface geological conditions under the seabed has been established. The results can be used by decision-makers to assess the suitability of individual areas for the installation of offshore wind turbines, both in relation to the thickness of soft sediments and the degree of geological complexity.

The documentation includes appendices: Better geological data for developing offshore wind - Overall geological mapping of the Danish sea area for the Danish Energy Agency. Appendix report. Geological Survey of Denmark and Greenland Report 2025/29.

Vangkilde-Pedersen, T., Christensen, N., Nørgaard-Pedersen, N., Allaart, L., Bennike, O., Leth, J.O., Winther, L.H., Sandersen, P.B.E., Prins, L.T., Singhroha, S. & Pérez, L.F. 2025. Better geological data for developing offshore wind. Overall geological mapping of the Danish sea area for the Danish Energy Agency. Geological Survey of Denmark and Greenland Report 2025/29.

Prins, L.T. & Andresen, K.J. 2019: Buried late Quaternary channel systems in the Danish North Sea – genesis and geological evolution. Quaternary Science Reviews 223, 105943. https://doi.org/10.1016/j.quascirev.2019.105943

van der Vegt, P., Janszen, A. & Moscariello, A. 2012: Tunnel valleys: Current knowledge and future perspectives. In: Huuse, M., Redfern, J., Le Heron, D.P., Dixon, R., Moscariello, A. & Craig, J. (eds): Glaciogenic reservoirs and hydrocarbon systems. Geological Society, Special Publications, London 368, 75–97. https://doi.org/10.1144/sp368.13

Ottesen, D., Stewart, M., Brönner, M. & Batchelor, C.L. 2020: Tunnel valleys of the central and northern North Sea (56◦N to 62◦N): distribution and characteristics. Marine Geology 425, 106199. https://doi.org/10.1016/j.margeo.2020.106199

Kirkham, J.D., Hogan, K.A., Larter, R.D., Self, E., Games, K., Huuse, M., Stewart, M.A., Ottesen, D., Le Heron, D.P., Lawrence, A., Kane, I., Arnold, N.S. & Dowdeswell, J.A. 2024: The infill of tunnel valleys in the central North Sea: Implications for sedimentary processes, geohazards, and ice-sheet dynamics. Marine Geology 467, 107185.

https://doi.org/10.1016/j.margeo.2023.107185

Sandersen, P.B.E. & Jørgensen, F. 2016: Kortlægning af begravede dale i Danmark. Opdatering 2015. GEUS Særudgave, december 2016, bind 1 og 2.

https://www.begravededale.dk/PDF_2015/091116_Rapport_Begravede_dale_BIND_1_Endelig_udgave_Low_res.pdf

Al Hseinat, M. & Hubscher, C. 2017: Late Cretaceous to recent tectonic evolution of the north German Basin and the transition zone to the Baltic Shield/Southwest Baltic Sea. Tectonophysics 708, 28–55. https://doi.org/10.1016/j.tecto.2017.04.021

Jensen, J.B. & Bennike, O. 2022: Geological Screening of Kriegers Flak North and South. Geological seabed screening in relation to possible location of windfarm areas. GEUS Rapport 2022/2. https://doi.org/10.22008/gpub/34637

Lange, D., 1984: Geologische Untersuchungen an spätglazialen und holozänen Sedimenten der Lübecker und Mecklenburger Bucht. Unveröffentlichte Dissertation (B), Institut für Meereskunde Warnemünde, 166 S.

Kjær, K.H., Houmark-Nielsen, M., Richardt, N. 2003: Ice-flow patterns and dispersal of erratics at the southwestern margin of the last Scandinavian ice sheet: signature of palaeo-ice streams. Boreas 32: 130–148. https://doi.org/10.1111/j.1502-3885.2003.tb01434.x

Pedersen, S.A.S. 2005: Structural analysis of the Rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark. Geological Survey of Denmark and Greenland Bulletin 8, 192 pp. https://doi.org/10.34194/geusb.v8.5253

Phillips, E., Cotterill, C., Johnson, K., Crombie, K., James, L., Carr, S. & Ruiter, A. 2018: Large-scale glacitectonic deformation in response to active ice sheet retreat across Dogger Bank (southern central North Sea) during the Last Glacial Maximum. Quaternary Science Reviews 179, 24-47. https://doi.org/10.1016/j.quascirev.2017.11.001

Phillips, E., Johnson, K., Ellen, R., Plenderleith, G., Dove, D., Carter, G., Dakin, N. & Cotterill, C. 2022: Glacitectonic evidence of ice sheet interaction and retreat across the western part of Dogger Bank (North Sea) during the Last Glaciation. Proceedings of the Geologists' Association 133, 87-111. https://doi.org/10.1016/j.pgeola.2021.11.005

Szuman, I., Kalita, J. Z., Diemont, C. R., Livingstone, S. J., Clark, C. D., and Margold, M. 2024: Reconstructing dynamics of the Baltic Ice Stream Complex during deglaciation of the Last Scandinavian Ice Sheet, The Cryosphere, 18, 2407–2428. https://doi.org/10.5194/tc-18-2407-2024.

Pedersen, S.A.S. & Boldreel, L.O. 2017: Glaciotectonic deformations in the Jammerbugt and glaciodynamic development in the eastern North Sea. Journal of Quaternary Science 32, 183–195. https://doi.org/10.1002/jqs.2887

The dataset was produced by GEUS for the Danish Energy Agency as part of a geological screening of the entire Danish marine area to support offshore wind planning. The maps show the thickness of Late Glacial and Holocene deposits and derived themes related to potentially soft sediments and geological complexity.

The mapping is based on interpretation of new and existing shallow seismic data and vibrocore samples. The results represent a large-scale, regional geological assessment without detailed lithological differentiation between sand and clay/mud.

Separate maps of Late Glacial and Holocene deposits, as well as a map of their combined thickness, were produced and used to classify marine areas according to the likelihood of foundation-related challenges. The results serve as decision support in the Danish Energy Agency’s overall assessment of suitable areas for offshore wind development.