Seismic stratigraphy and sedimentary architecture of the Chalk Group in south-west Denmark

Connie Larsen,Jon Ineson,Lars Ole Boldreel

doi:10.34194/geusb.v31.4642

Connie Larsen, Jon Ineson + Show 1 more

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https://doi.org/10.34194/geusb.v31.4642

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Abstract

The Chalk Group is ubiquitous in the subsurface of the Danish Basin and its upper levels are exposed locally onshore, most notably in eastern Denmark. Although many subsurface studies have been made of the group in the Danish Basin, most of these have been in the eastern part of Denmark (e.g. Esmerode et al. 2007; Surlyk & Lykke-Andersen 2007) whereas the stratigraphy and character of the Chalk Group in the western onshore region is less well-known. The work described here was undertaken as a BSc project at the Department of Geosciences and Natural Resource Mangement at the University of Copenhagen by the first author as part of regional seismic mapping work contributing to an evaluation of the geothermal energy potential in Denmark. The aim of this paper is to present a summary of the key results of the study. We have subdivided and mapped the distribution of the Chalk Group in the northern North German Basin and the south-western Danish Basin based on digital reflection seismic profiles. We also highlight seismic architectural features that testify to periods of active bottom currents.

Highlights

The Chalk Group is ubiquitous in the subsurface of the Danish Basin and its upper levels are exposed locally onshore, most notably in eastern Denmark
The subdivision of the Chalk Group is based on seismic facies analysis and seismic structural analysis, and the resultant seismic units are correlated to wireline-logs and stratigraphic units from seven deep boreholes (Fig. 1)
In the northern part of the study area, the Chalk Group is subdivided into 10 seismic units but the uppermost unit is absent south of the Ringkøbing–Fyn High, i.e. only nine units are recognised in this area (Figs 1, 2)

Summary

Introduction

The Chalk Group is ubiquitous in the subsurface of the Danish Basin and its upper levels are exposed locally onshore, most notably in eastern Denmark. Many subsurface studies have been made of the group in the Danish Basin, most of these have been in the eastern part of Denmark The work described here was undertaken as a BSc project at the Department of Geosciences and Natural Resource Mangement at the University of Copenhagen by the first author as part of regional seismic mapping work contributing to an evaluation of the geothermal energy potential in Denmark. We have subdivided and mapped the distribution of the Chalk Group in the northern North German Basin and the south-western Danish Basin based on digital reflection seismic profiles. The pelagic chalk deposits were subject to redistribution by various processes including downslope mass-flow movements from

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Conclusion