In the Late Devonian–earliest Mississippian, Svalbard was affected by a short-lived episode of deformation named the Ellesmerian (Svalbardian) Orogeny. This event resulted in intense folding and thrusting in Devonian sedimentary successions. Deformation stopped prior to the deposition of Carboniferous–Permian sedimentary strata of the Billefjorden and Gipsdalen groups, which lie unconformably over folded Devonian strata. Later on, presumed Ellesmerian structures were reworked during Eurekan tectonism in the early Cenozoic and partly eroded. At present, record of Ellesmerian deformation is only preserved in narrow N–S-trending belts in central–northern, western and southern Spitsbergen. Despite extensive field studies, the timing of the Ellesmerian Orogeny is poorly constrained, and remains a matter of debate in places because of conflicting ages and because of the complex tectonic history of Svalbard. The present contribution aims at reviewing and discussing all available age constraints for Ellesmerian tectonism in Svalbard, which has great implications for the plate tectonic reconstructions of Arctic regions and for the tectonic history of Svalbard.
