Palaeogene Alpine tectonics and Icelandic plume-related magmatism and deformation in Northern Ireland

• Published in: Journal of the Geological Society
• Main Authors: Cooper, M.R., Anderson, H., Walsh, J.J., Van Dam, C.L., Young, M.E., Earls, G., Walker, A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of London 2012
• Subjects: North Atlantic
• Online Access: http://nora.nerc.ac.uk/id/eprint/16421/; https://nora.nerc.ac.uk/id/eprint/16421/1/Cooperetal_Tellusdykes_JGS_accepted_version_text_only.pdf

The Cenozoic tectonic history of NW Europe is generally attributed to some combination of three principal controlling factors: North Atlantic opening, Alpine collision and formation of the Icelandic mantle plume. Using constraints from the high-resolution Tellus aeromagnetic survey of Northern Ireland, we show that Palaeogene tectonics can be attributed to approximately north–south Alpine-related compression, forming NNW–SSE-trending dextral and ENE–WSW-trending sinistral conjugate strike-slip faults, with the latter defined by kilometre-scale displacements along reactivated Caledonian or Carboniferous faults. This tectonism was, however, punctuated by pulsed magmatic intrusive and extrusive events, including four distinct dyke swarms that are attributed to NE–SW- to east–west-directed plume-related extension. Although this evidence shows, for the first time, that north–south Alpine compression was periodically overwhelmed by the dynamic stresses and uplift associated with pulsed mantle plume-related deformation, associated strike-slip faulting may have controlled the locus of volcanic activity and central igneous complexes, and the location of sedimentary depocentres.