Brian J. Todd

High-resolution seismic and sidescan sonar surveys on Saglek Bank indicate extensive areas of iceberg-scoured seabottom. The scour trends and abundance are compared with iceberg trajectories and oceanic current information. Saglek Bank shows heavy scouring (50 to 100% of the seabed shows clearly defined scour marks) on its north-facing bank edge (175 to 250m water depth) where the iceberg-carrying Labrador Current impinges. The eastern and western bank margins show moderate to heavy scouring (25 to 75%) while the bank top at water depths less than about 150m is heavily scoured. The differences in the amount of scouring are interpreted as resulting from variations in iceberg flux, iceberg draft and bathymetry, combined with different rates of scour obliteration. The orientation of the scours generally parallel the blank edges i.e. northwest-southeast. A cross-shelf saddle and a trough subdivide and demarcate Saglek Bank. Okak Saddle shows a complicated orientation pattern, with an east-west relict scour tend as well as the modern northwest-southeast direction, while Karlsefni Trough shows no relict scour marks. Iceberg scour trends generally reflect the direction of oceanic flow and modern iceberg movements. These movements are primarily controlled by currents which in turn are influenced by the shelf bathymetry. Local direct bathymetric control of iceberg movement has been recognized in shelf areas of low translatory current strength.

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Supervisor: C.F. Michael Lewis