The origin of the West Spitsbergen Fold Belt from geological constraints and plate kinematics: Implications for the Arctic

Abstract

The West Spitsbergen Fold Belt, which extends for 300 km along the western margin of Svalbard and is up to 80 km wide, has much in common with foreland fold and thrust belts. The near-foreland segment of the fold belt exhibits ramp-flat thrust trajectories whilst structurally higher nappes are typified by more listric thrusts. Higher nappes to the west contain imbricated Carboniferous and basement rocks showing that the latter were actively involved in the fold belt deformation and a minimum of 80 km total shortening perpendicular to the western margin of Svalbard is estimated. The early stages of the Eurekan deformation in North Greenland can be linked to that of the West Spitsbergen Fold Belt and the combined shortening across the two fold belts may exceed 80 km. In Ellesmere Island Eurekan structures are distributed in an arc-like belt which records between 50 to 100 km of shortening since the Late Cretaceous. Kinematic reconstructions suggest that before the opening of the Eurasian Basin and Norwegian-Greenland Sea (Chron 25), Svalbard was linked to North America. In the Late Cretaceous-Palaeocene interval the motion across the Greenland-Svalbard margin, was mainly convergent giving rise to the West Spitsbergen Fold Belt and the Eurekan structures of North Greenland. The dextral separation of Greenland and Svalbard in post-Chron 24 time was accompanied by extension followed by pure extension in post-Chron 13 time.