Kane Seamount in the Cape Verde Basin, eastern Atlantic

Abstract

In the Cape Verde Basin at 21° 09′N, 28° 02′W, the newly discovered Kane Seamount rises about 1300 m above a lower continental rise environment. Although the age of the seamount has not been determined, the surrounding sea floor is thought to be on the order of 110 m.y. old. Regional sediment thicknesses are generally 400–500 m. To the north and east, there is a moat at the base of the seamount created on the east by sediment pinchout, whereas to the southeast and south, parallel-bedded, subbottom layers thicken toward the flanks, forming a stratified sediment accumulation which is associated with a SW-trending ridge. Analysis of foraminifera from a core collected along the sediment accumulation suggests an average deposition rate of 0.4 cm/1000 years for the past 1.8–2.2 m.y. Sediment cores taken in a turbidite sequence occurring within the moat contain interrupted stratigraphic sequences indicative of depositional irregularity. Bottom current flow, concentrated around the base of the seamount, probably created the existing moat and sediment accumulation either by prolonged nondeposition in a weak current regime as presently exists in the eastern Atlantic basin, or by alternating periods of deposition and erosion in a regime of generally stronger, variable currents during the Plio-Pleistocene.