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Title: Structural evolution of the northern Danish Central Graben
Author: Melgaard, Thomas
ISNI:       0000 0004 2749 2076
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2006
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This thesis compiles the results of a 3D seismic-based study of the structural evolution of the Danish Central Graben. Detailed interpretation of the geometry, structural and stratigraphic context has been carried out in order to advance our current understanding of the fundamental processes involved in major rift systems as well as to test previous published models, based on 2D seismic data, using recent 3D seismic data. The increased resolution provided by 3D seismic mapping of three key areas has allowed for fault patterns of complex structural elements in the Danish Central Graben to be imaged in three dimensions. The Mid North Sea High is essential for the identification of the basement fault trend and the Arne-Elin Graben is crucial for the determination of the fault trend influence on the Mesozoic deposition in combination with the salt-sediment interaction. Finally the western margin of the Ringkobing-Fyn High is central for the understanding of the origin of the Top Chalk Group depressional structures. Based on the interpretation a new model for the structural evolution for the Danish Central Graben has been proposed. In this model, the basement fault trend consists of a WNW-ESE and N-S rhomboidal fault pattern that formed prior to the Permian rifting of the North Sea. The interpretation of a rhomboidal basement fault trend in combination with salt-sediment interaction suggests less influence from strike-slip movement, which historically has been suggested for the deposition of the Mesozoic strata. The interpretation has revealed that salt-sediment interaction adopt a wide range of geometrical styles, ranging from fallen salt walls/diapirs, rising salt swells and diapirs and detached salt canopy in response to Jurassic rifting and Late Cretaceous/Early Palaeocene inversion of the Danish Central Graben. The regional 3D seismic imaging of Top Chalk Group horizon has revealed a number of enigmatic km-scale sub-circular structures. The spatial resolution of the 3D seismic data in combination with various attributes permitted the interpretation of enigmatic depressions as pockmarks that enlarged through sidewall collapse. The collapsed pockmarks occur on the flanks of major salt and inversion structures and may be of importance for the understanding of reservoir development in the uppermost Chalk Group.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available