Deep water masses and transports in the Vema Fracture Zone

Recent results from hydrographic, chlorofluoromethane (CFM) and current measurements during an R.V. Meteor cruise in February/March 1994 underscore the importance of the Vema Fracture Zone (VFZ), located near 11 degrees N on the Mid-Atlantic Ridge, for the transport of bottom water from the deep western basin of the equatorial Atlantic into the eastern 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 motion at 3640 m, was determined by a combination of geostrophic calculations and direct current observations by a lowered ADCP. The comparison to former results indicates that the eastward flow in the VFZ is rather persistent. The water mass properties (Theta, S and CFMs) in the VFZ were compared to stations in the Guiana Basin, in the equatorial channel, 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.