Abstract Terraces have been frequently observed and described along turbidite valleys. Many interpretations have been aimed at determining the origin of these structures, including a tectonic origin, succession of infilling and incision processes, channel-wall slumps, or inner levee aggradation. The Zaire submarine valley presents a complex structure with multiple terraces bordering a deep incised meandering thalweg. The detailed analysis of the morphology, the seismic structure and the recent sedimentation (in cores) along the Zaire upper-fan valley show that terraces are inner levees confined within the incised valley. Many terraces correspond to the infilling of abandoned meanders, and aggrade by deposition of turbidite sequences due to current overflows. The major process affecting the initiation and the development of terraces inside the valley is the vertical incision of the thalweg, simultaneously with meander migration.

Abstract The geological history of the Cap Ferret deep sea fan in the Bay of Biscay has been reconstructed using multichannel seismic reflection data, piston coring, echo sounding, and seabeam bathymetric data. Cap Ferret canyon is flat bottomed and several adjacent channels feed into it from the north. The canyon is tectonically controlled by a fault bordering its southern flank. Its continuation into deeper water is characterized by the buildup of sedimentary deposits which form a levee bordered on the south by a flat and complex channel. This linguoid morphology is of purely sedimentary construction. The southern area is further complicated by extensions of the Santander and Torrelavega canyons. Seismic stratigraphic interpretation of an extensive grid of multichannel seismic data (Miniflexichoc) provides the basis for interpretation of the geological history of the fan, a history that begins in the Upper Miocene following faulting of the continental platform.

ABSTRACT ODP Leg 105 drilled three sites (645, 646, 647) in Baffin Bay and the Labrador Sea. Paleontologic correlations with regional seismic reflectors established that glacial ice-rafting in the region started about 2.5 Ma (possibly as early as 3.4 Ma in Baffin Bay). Southward directed bottom water circulation in Baffin Bay started in early to mid-Miocene, while major drift sedimentation at Site 646 (Labrador Sea) started in the late Miocene. The opening of Baffin Bay occurred between 55 and 36 Ma. Oceanic crust at Site 647 (Labrador Sea) was dated as early Eocene in age (55-56 Ma, Chron 24).