| Summary: | Aeromagnetic data from the Røst Basin (RAS-03) were acquired in 2003 and merged with 12 neighbouring datasets. A compilation of the existing gravity data in the area has also been carried out. Forward 3D modelling along 17 profiles is constrained by available data on density, magnetic properties and reflection and refraction (OBS) seismics. The new data show that the previously interpreted oceanic fracture zones (Gleipne, Surt, Bivrost, Jenegga and Vesterålen) do not exist. Apparent offsets in the oceanic spreading anomalies were caused by poor navigation and wide line spacing of the vintage datasets. Consequently, opening of the Norwegian-Greenland Sea between the Jan Mayen and Senja-Greenland fracature zones occurred along a stable axis without offsets of the oceanic spreading anomalies of jumps in spreading axis. Reconstruction of the East Greenland aeromagnetic data to Chron 22 (c. 47.7 Ma) reveals that a c. 50 km wide igneous complex cut across the spreading anomalies 24A, 24B and 23 from the Vøring Marginal High on the Norwegian margin to the Traill Ø on the East Greenland coast. The complex (refereed to as Traill Ø-Vøring igneous complex in the present report) links up with the NE-SW trending initial magmatic lineament (IML) between the Traill Ø and the opening history and excludes the need to invoke the abandoned spreading ridge and the Gleipne Fracture Zone along the Vøring margin.(Forkortet) 51027
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