Deep crustal geometry: An integrated geophysical study of an exhumed eclogite terrain, Bergen area, Southwest Norway

Crustal P-wave and density models of the southwest Norwegian margin are constructed from two wide-angle seismic reflection/refraction and gravity transects to illuminate the structure beneath the exhumed eclogite terrain of the Bergen Arcs, Western Gneiss Region, and the adjacent North Sea. Dipping crustal reflectors may represent Caledonian mylonitized or eclogitized shear zones in the crust. Flat-lying lower-crustal reflectors may be basal shear zones or compositional boundaries. Depth to the Mohorovicic discontinuity dives from 21 km beneath the Viking Graben to close to 40 km beneath the Norwegian continent. Modeled mantle refractions and densities indicate normal mantle Pn velocities and densities (8.1-8.2 km/s and 3330 kg/m3) in the study area. Lower crustal P-wave velocities between 6.8 km/s and 7.0 km/s and a maximum lower crustal density of 2900 kg/m 3 are interpreted as mafic granulite.