Partitioning of lithosphere stretching and thinning at continental rifted margins between pre- and syn-breakup deformation : Norwegian margin study

• Main Author: Watson, John Galbraith
• Published: University of Liverpool 2012
• Subjects: 551
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569251

The Norwegian rifted continental margin was formed by the breakup at 55Ma and earlier Mesozoic rifting of the North Atlantic. The continental margin reveals pre-breakup lithosphere deformation during the Triassic, Jurassic and Cretaceous Periods. This study examines the Lofoten, Vering and Mere margin segments in order to better understand the evolution of the Norwegian margin. Interpreted seismic crustal profiles have been analyzed to determine continental lithosphere thinning and upper crustal extension from the Triassic Period to present day. Continental crustal structure and thinning coupled with the location of both the ocean continent transition (OCT) and the continent ocean boundary (COB) have also been addressed. This study shows that the Norwegian rifted margin experienced breakup depth-dependent lithosphere stretching and thinning where whole lithosphere stretching and thinning exceeds that of the upper crust. Earlier pre- breakup lithosphere deformation during the Triassic, Jurassic and Early Cretaceous rifting is shown to be depth-uniform leading to intra-continental rift basin formation. The non-coaxial superposition of lithosphere thinning from the earlier intra-continental rift events with Early Tertiary breakup thinning has led to a complex and laterally varying distribution of thinned continental lithosphere. It is important to understand the structure and rifting history in order to partition the stretching and thinning of the Norwegian continental margin lithosphere. By these methods better predictions of the subsidence and heat flow histories of the Norwegian margin can be deduced.