Evidence for Quaternary convergence across the North America- South America plate boundary zone, east of the Lesser Antilles

New seismic and bathymetric data reveal that the plate boundary zone between the North American and South American plates, east of the Caribbean, has occupied a >200-km-wide zone of localized basement uplift and folding, and of faulting of the sedimentary cover, during the early Pleistocene to Holocene. This zone, which includes the Barracuda Ridge and Tiburon Rise, exhibits north-south compressional structures and continues eastward up to 500 km from the boundary of the Caribbean plate. A sequence of young turbiditedominated sediments fi lls the basin between these two ridges and shows synsedimentary deformation; the base of the sequence is of early Pleistocene age, dated by biostratigraphic correlation with Deep Sea Drilling Project Site 27. Recent deformation in the turbidite-fi lled trough north of the Barracuda Ridge is shown by uplift of the seafl oor at the crests of anticlines, across which the shallowest sediment layers thin or pinch out.