Single-channel and multichannel seismic reflection profiles of the North Scotia ridge trending west-east off southernmost South America show the north side to consist of a wedge of deformed sediments resting on a planar layered sequence. Relative movement of the ridge northward toward the Falkland plateau has resulted in deformation and uplift of the near-surface sediment layers of the Falkland trough to form an accretionary wedge; the sediments are ≂1 to 3 s of two-way travel time in thickness and lie above a well-defined reflector-whose velocity at the northern part of the trough is 3.6 km/s. The deeper layers extend to depths, in places, greater than 9.0 s of two-way travel time beneath the north slope without any significant deformation. The deepest observed reflector is associated with a 5.9-km/s basement. The deformed pile of sediments, or collision zone, of the North Scotia ridge is similar to that observed at other active, compressive plate boundaries.