DEEP-WATER MASSES AND TRANSPORTS IN THE VEMA FRACTURE-ZONE

Recent results from hydrographic, chlorofluoromethane (CFM) and curren t measurements during an R.V. Meteor cruise in February/March 1994 und erscore the importance of the Vema Fracture Zone (VFZ), located near 1 1 degrees N on the Mid-Atlantic Ridge, for the transport of bottom wat er from the deep western basin of the equatorial Atlantic into the eas tern abyss. The eastward transport in the bottom water range, of 1;8-2 .0 Sv below 2.0 degrees C, and of 2.1-2.4 Sv below the level of no mot ion at 3640 m, was determined by a combination of geostrophic calculat ions and direct current observations by a lowered ADCP. The comparison to former results indicates that the eastward flow in the VFZ is rath er persistent. The water mass properties (Theta, S and CFMs) in the VF Z were compared to stations in the Guiana Basin, in the equatorial cha nnel, and in the Brazil Basin at 10 degrees S suggesting a significant contribution of North Atlantic Deep Water to the entire bottom water layer in the VFZ. Copyright (C) 1996 Published by Elsevier Science Ltd .