THE WEST SPITSBERGEN FOLD BELT - THE RESULT OF LATE CRETACEOUS-PALEOCENE GREENLAND-SVALBARD CONVERGENCE

The West Spitsbergen Fold Belt, together with the Eurekan structures o f northern Greenland and Ellesmere Island, are suggested to be the res ult of Late Cretaceous-Palaeocene intracontinental compressional tecto nics. The Late Palaeozoic - Mesozoic rocks of western Spitsbergen are characterized by near-foreland deformation with ramp-flat, top-to-the east thrust trajectories, whereas structurally higher nappes involving Caledonian complexes are typified by more listric thrusts and mylonit e zones. A minimum of 40 km of shortening is estimated for the norther n part of the West Spitsbergen Fold Belt. The axial trends in the West Spitsbergen and the North Greenland Eurekan fold belts parallel the p rincipal fault zones which accommodated the separation of Greenland an d Svalbard after Chron 25/24. In northern Greenland, north directed Eu rekan thrusts associated with mylonites and cleavage formation represe nt at least 10 km of shortening. Between 50 and 100 km of shortening i s estimated for the markedly arcuate Eurekan Fold Belt of Ellesmere Is land, but the principal tectonic transport is eastwards. Kinematic rec onstructions suggest that Svalbard was linked to North America before the opening of the Eurasian Basin and Norwegian - Greenland Sea. In th e Late Cretaceous - Palaeocene interval, the relative motion between G reenland and North America was convergent across the Greenland - Svalb ard margin, giving rise to the West Spitsbergen Fold Belt and the Eure kan structures of North Greenland.