Delineation of tunnel valley across the North Sea coastline, Denmark based on reflection seismic data, boreholes, TEM and Schlumberger soundings.

Theis Raaschou Andersen, Flemming Jørgensen, Steen Christensen

Research output: Contribution to conference without a publisher/journalPaperResearch


Buried tunnel valleys are elongated depressions eroded into the substratum during the Pleistocene glaciations. Nine such valleys are mapped on- and offshore in a 300 km2 area located at the Danish North Sea coast. The delineation of the buried valleys is based on an extensive data set consisting of on- and offshore 2D seismic data, TEM (Transient Electro-Magnetic) soundings, Schlumberger soundings, and boreholes. The valleys are observed as discrete incisions with three overall orientations: SSE – NNW, ESE – WNW, and SSW – NNE. They have depths between 75 and 185 m, widths up to 1.8 km, and lengths from 7 to 25 km. The infill comprises till, glaciofluvial sand, and glaciolacustrine clay and silt. Younger tunnel valleys are found to often re-use pre-established valleys generating cut-and-fill structures which are clearly revealed on the reflection seismic profiles. Cross-cutting relations, preferred orientations, and morphology support that three of the tunnel valleys cross the North Sea coastline. It is suggested that the nine valleys were formed during at least six events that occurred through one or more pre-Weichselian glaciations.
Key words: Pleistocene valleys, geophysical mapping, reflection seismic data, 3D geological models
Original languageEnglish
Publication dateAug 2016
Publication statusPublished - Aug 2016
EventASEG-PESA 2016: 25th Geophysical Conference & Exhibition - Adelaide, Australia
Duration: 21 Aug 201624 Aug 2016


ConferenceASEG-PESA 2016
Internet address


  • geotechnics

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