The Structural Evolution of the Faroe Islands, NE Atlantic Margin

• Main Author: WALKER, RICHARD,JAMES
• Format: Thesis
• Language: unknown
• Published: 2010
• Subjects: NE Atlantic margin; Faroe Islands; Faults in basalt; North Atlantic
• Online Access: http://etheses.dur.ac.uk/134/; http://etheses.dur.ac.uk/134/1/Richard_Walker_PhD_Thesis_2010_-_The_Structural_Evolution_of_the_Faroe_Islands_NE_Atlantic_Margin.pdf

The NE Atlantic margin plays host to numerous basins, developed in phases from the Devono-Carboniferous through to the Cenozoic, which record the build up to plate separation and formation of the North Atlantic Ocean. Existing models for this invoke broadly NW-SE extension within the basins, which are segmented by regional-scale NW-SE trending strike-slip lineaments, which are commonly termed ‘transfer zones’. However, there is a general paucity of information concerning the true kinematics of the so-called transfer zones. In this study, the Palaeogene and later structural evolution of the NE Atlantic margin is investigated using abundant field data collected on the Faroe Islands, and systematic observations that characterise the related deformation structures developed in the Faroe Islands Basalt Group (FIBG). Structures in the Faroe Islands provide evidence for a 6-stage tectonic evolution, here split into 3 broad phases: (1a) E-W to NE-SW extension, accommodated by dip-slip N-S and NW-SE trending faults. Continued NE-SW extension (1b) was then accommodated by the emplacement of a regionally significant NW-SE- and NNE-SSW-oriented dyke swarm. Event 1 affects the majority of the FIBG stratigraphy, resulting in thickness variations, most notably across the Judd, Brynhild and Westray (‘transfer’) fault-zones. Continued magmatism and anticlockwise rotation of the extension vector led to (2a) the emplacement of ENE-WSW and ESE-WNW conjugate dykes, followed by intrusion of the large, saucer-shaped sills on the islands. Their intrusion heralded the onset of N-S crustal extension and was followed by (2b) crustal extrusion involving both E-W shortening and further N-S extension facilitated primarily by slip on ENE-WSW (dextral) and ESE-WNW (sinistral) conjugate strike-slip faults, interlinked with minor NE and SW dipping thrust faults. During the final stages of this event (2c), the regional extension vector rotated into a NW-SE orientation that was accommodated predominantly by slip along NE-SW oriented ...