CRUSTAL STRUCTURE BETWEEN THE KNIPOVICH RIDGE AND THE VAN MIJENFJORDEN (SVALBARD)

Abstract

The Alfred Wegener Institute of Polar and Marine Research, the University of Bergen and Hokkaido University acquired new seismic refraction data along a transect from the Knipovich Ridge to the inner Van Mijenfjorden in southern Svalbard. A close spacing of on- and offshore receivers and a dense marine shot pattern provide the data for a high resolution p-wave velocity model for geological interpretation. Additional new seismic reflection data (University of Bergen) yield structural information for a more reliable analysis. Crustal thickness along the Van Mijenfjorden is 33 to 34 km. Seismic velocities of 5.0 km/s are observed within the upper crustal section of the Tertiary Central Spitsbergen Basin. A Paleozoic sedimentary basin with a depth of 8 to 10 km is associated with the Nordfjorden Block. The seismic velocities are up to 6.0 km/s. Paleozoic sedimentary rocks are expected further to the west of the Hornsund Lineament since seismic velocities reveal a similar range here. West of the Bellsund the continental crust thins gradually over a 90 km wide rifted zone.