A combined biostratigraphic and seismic study was performed on three holes drilled in the western Barents Sea. Two holes penetrate the thick sedimentary wedge which forms a large fan located off a trough on the Barents Sea Shelf, the Bjornoyrenna Fan. The study shows that the fan was built over a short time span in the late Pliocene-Pleistocene, mainly due to glacial erosion of the Barents Shelf region. This contrasts earlier age assignments which concluded that fan-deposition started in the Oligocene. The results have a major impact on the understanding of trough mouth fan formation and has important bearing on the history of the sedimentary basins of the Barents Shelf.