Effects of Multiple Detachment Layers on Faulting in the UK Southern North Sea

Aji Kyari

Research output: ThesisDoctoral Thesis

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This thesis presents an analysis of detached extensional fault systems in the Southern North Sea. The research involved the interpretation of 3D seismic data from the Guinevere and Camelot fields, quantitative fault analysis and 2D section reconstructions and restorations.
The UK Southern North Sea is characterized by the presence of complex Mesozoic grabens trending NW-SE. A prominent feature of these grabens is the presence of Lower Triassic Separation Zones (LTSZ), which are characterized by the absence of the Lower Triassic Bunter Group (Bunter shale and sandstone). A new model for the evolution of these structures is proposed; the suggested mechanisms are salt tectonics and extensional faulting utilizing multiple detachment layers of the Permian Zechstein and Triassic Haisborough Groups in two different phases of extension.
The 3D seismic interpretation results of the Jurassic equivalent units from the two fields (Guinevere and Camelot) shows arrays of domino faults with an oblique extensional direction (ENE) relative to the elongate graben bounding listric faults system which have a dominant (NW-SE) direction. The curvature of these ENE faults is controlled by underlying faults at the Upper Triassic level; where the faults are reactivated the Triassic faults link up with the overlying Jurassic faults, where not reactivated they tend to control the curvature of the overlying faults.

Seismic attribute analysis and 2D section restorations and reconstruction have been carried out on selected seismic lines to determine the structural and tectonic evolution of the basin and to test the plausibility of the proposed model.
The proposed model was compared with basins that have similar structures, such as the East Irish Sea basin and the passive margins of Angola and Congo. This research has also shown that the term “Triassic-Jurassic extension” previously used to describe extension in the Mesozoic in parts of the Southern North Sea is better described as two different and separate extensional events.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Adam, Jurgen, Supervisor
Thesis sponsors
Award date1 Sept 2018
Publication statusUnpublished - 2018

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