Downsizing the Mjølnir impact structure, Barents Sea, Norway

Stratigraphic relationships indicate that the submarine Mjølnir impact structure in the SW Barents Sea is of Cretaceous age (~ 142 Ma) and the impact palaeolatitude is estimated at 56°N. Though the crater has been intensively studied, its dimensions at depth are uncertain.Density and magnetic susceptibility measurements of core samples are presented and used to interpret a newly available aeromagnetic survey and gravity data, and to model the potential field anomaly data of the area jointly, so as to constrain better the signature of the crater. Forward modelling suggests that the crater diameter is about 20 km, and thus needs downscaling to about half of the earlier proposed size.