Gulf Stream: Reconstruction of Cenozoic flow patterns over the Blake Plateau

Abstract

Rugged and channeled topography excavated on the top of Paleocene strata and buried by lower Eocene deposits indicates that Gulf Stream interaction with the Blake Plateau occurred as early as late Paleocene-early Eocene time. Initially, the Gulf Stream flowed across the western edge of the Blake Plateau in an area now covered by the Florida-Hatteras slope. By early Eocene, the current had shifted 200 km to the south, cutting channels 500 m bathymetrically lower across the central Blake Plateau and exiting just north of the Blake Spur. The Gulf Stream flowed northeastward across the central plateau throughout the Eocene and returned to near its Paleocene position across the western edge of the plateau in the middle Oligocene; shortly thereafter it resumed its former track across the central plateau. Since the early Miocene, the current axis has alternated between a northeasterly flow path across the central Blake Plateau and a more northerly course along the inner Blake Plateau. Shifts in the position of the Gulf Stream are the result of eastward and southward deflection of the current by a prominent bathymetric high, the Charleston Bump, during periods of sea-level lowering.