Fig. 1.

The Norwegian continental margin. a. Large-scale ocean-surface circulation in the North Atlantic. NAC – North Atlantic Current. CSC – Continental Slope Current. FS – Fram Strait. Circles represent sources of deep water (simplified from Hansen and Østerhus, 2000). b. Norwegian continental margin morphology showing shallow banks adjacent to major deep glacial cross-shelf troughs incised into the shelf and branches of ocean-surface circulation in the Norwegian Sea (modified from Hansen and Østerhus, 2000) in the study area (white box, Fig. 4, Fig. 5a,b,c). Red, thick semi-transparent lines show the major prevailing surface currents (NwAC – Norwegian Atlantic Current and its major branches: NwAFC – Norwegian Atlantic Front Current and NwASC - Norwegian Atlantic Slope Current). NCC - Norwegian Coastal Current. Thicknesses of red lines are roughly proportional to mass fluxes of respective currents, in Sv (from Gascard et al., 2004); 1 Sv = 10⁶ m³ s^− 1. Yellow arrowed lines represent mean velocity vectors computed from combined drogued and wind-corrected undrogued drifter observations from August 1991 to December 1994 (Poulain et al., 1996). Small red line segments show iceberg ploughmarks preserved on the modern seafloor and interpreted from the available 3D seismic cubes. Thin black line shows the 2D dip seismic line GMNR94-106. 3D seismic data coverage of the study area is represented by semi-transparent white areas. Thick black line shows the transect between Faeroe and Shetland Islands (Fig. 1c). c. Schematic diagram of the typical distribution of the main water masses with arrows indicating general flow through the section. Water masses: NAW - North Atlantic Water, MEIW Modified East Icelandic Water, NSDW Norwegian Sea Deep Water. Modified from Gould et al. (1985) and Hansen and Østerhus (2000). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)