Onshore evidence for progressive changes in rifting directions during continental break-up in the NE Atlantic

Walker, Richard James, Holdsworth, R. E., Imber, J. and Ellis, D. 2011. Onshore evidence for progressive changes in rifting directions during continental break-up in the NE Atlantic. Journal of the Geological Society 168 (1) , pp. 27-48. 10.1144/0016-76492010-021

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Abstract

Current models for the Palaeogene-aged continental break-up in the North Atlantic invoke a NW–SE extension vector throughout the rift-to-drift process, accommodated by margin-parallel normal faults, and margin-oblique (strike-slip) transfer zones. However, Palaeogene and younger faults in the Faroe Islands provide evidence for a progressive anticlockwise rotation in extension vectors immediately prior to and following North Atlantic break-up. Six deformation stages are recognized: (1) east–west to NE–SW extension, accommodated by dip-slip north–south- and NW–SE-trending faults; (2) continued NE–SW extension accommodated by NW–SE- and NNE–SSW-oriented dykes; (3) north–south extension accommodated by ENE–WSW and ESE–WNW conjugate dykes; (4) crustal extrusion involving both east–west shortening and further north–south extension along ENE–WSW (dextral) and ESE–WNW (sinistral) conjugate strike-slip faults; (5) during the final stages of rifting, the regional extension vector became NW–SE and was accommodated predominantly by slip along NE–SW dextral oblique-slip faults; (6) pre-existing structures were locally reactivated as tensional and extensional–shear features, characterized by the entrainment of clastic material along fault planes. The present study reveals a distinct period of margin-parallel extension immediately prior to break-up that is not accounted for by existing models, illustrating the importance of conducting field-based studies to validate otherwise widely accepted margin-scale models worldwide.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GC Oceanography Q Science > QE Geology
Publisher:	Geological Society of London
ISSN:	0016-7649
Last Modified:	19 Mar 2016 22:18
URI:	https://orca.cardiff.ac.uk/id/eprint/11308

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