Basement structure and its influence on the structural configuration of the northern North Sea
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Published version
Author(s)
Fazli Khani, H
Fossen, H
Gawthorpe, RL
Faleide, JL
Bell, RE
Type
Journal Article
Abstract
The northern North Sea rift basin developed on a heterogeneous crust comprising structures inherited from the Caledonian orogeny and Devonian postorogenic extension. Integrating two-dimensional regional seismic reflection data and information from basement wells, we investigate the prerift structural configuration in the northern North Sea rift. Three seismic facies have been defined below the base rift surface: (1) relatively low-amplitude and low-frequency reflections, interpreted as pre-Caledonian metasediments, Caledonian nappes, and/or Devonian clastic sediments; (2) packages of high-amplitude dipping reflections (>500 ms thick), interpreted as basement shear zones; and (3) medium-amplitude and high-frequency reflections interpreted as less sheared crystalline basement of Proterozoic and Paleozoic (Caledonian) origin. Some zones of Seismic Facies 2 can be linked to onshore Devonian shear zones, whereas others are restricted to the offshore rift area. Interpreted offshore shear zones dip S, ESE, and WNW in contrast to W to NW dipping shear zones onshore West Norway. Our results indicate that Devonian strain and ductile deformation was distributed throughout the Caledonian orogenic belt from central South Norway to the Shetland Platform. Most of the Devonian basins related to this extension are, however, removed by erosion during subsequent exhumation. Basement shear zones reactivated during the rifting and locally control the location and geometry of rift depocenters, e.g., in the Stord and East Shetland basins. Prerift structures with present-day dips >15° were reactivated, although some of the basement shear zones are displaced by rift faults regardless of their orientation relative to rift extension direction.
Date Issued
2017-06-29
Date Acceptance
2017-06-01
Citation
Tectonics, 2017, 36 (6), pp.1151-1171
ISSN
1944-9194
Publisher
American Geophysical Union (AGU)
Start Page
1151
End Page
1171
Journal / Book Title
Tectonics
Volume
36
Issue
6
Copyright Statement
© 2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the
original work is properly cited, the use is
non-commercial and no modifications
or adaptations are made.
original work is properly cited, the use is
non-commercial and no modifications
or adaptations are made.
Sponsor
Research Council of Norway
Grant Number
125000/807097
Subjects
Geochemistry & Geophysics
0403 Geology
0404 Geophysics
Publication Status
Published