The margin between Senja and Spitsbergen fracture zones: Implications from plate tectonics

Abstract

Analysis of multichannel seismic data from the continental margin off Svalbard between the Senja and Spitsbergen fracture zones suggests that the transition between continental and oceanic crust is located at or close to the Hornsund Fault Zone. In the Late Paleocene/Early Eoeene (57 m.y.) the region between Svalbard and Northeast-Greenland was subjected to regional shear movements associated with a transform system between the young Lofoten-Greenland Basin and the Arctic Ocean. Approximately 50 m.y. ago the spreading axis migrated to the northeast creating a deep basin north of the Greenland-Senja Fracture Zone forming the passive margin between Bear Island and 76.5°N. North of 76.5°N the regional transform was maintained. At the time of the main reorganization of relative plate motion (36 m.y.) the northern margin evolved. A continental fragment was possibly cut off from the Svalbard margin forming a small microcontinent. The microcontinent appears as the submarine ridge which has been associated with the Hovgaard Fracture Zone. It is suggested that the sediments west of the Hornsund Fault Zone are not older than Eocene in the south and mid-Oligocene in the north. The position of the spreading axis has greatly influenced the margin sedimentation.