Sediment Transport by the Antarctic Bottom Current on the Bermuda Rise

• DOI: 10.1038/211611a0
• Publication Date: 2006-07-06T00:42:10Z
• Authors: B. C. HEEZEN; E. D. SCHNEIDER; O. H. PILKEY
• Keywords: Geostrophic current; Antarctic Bottom Water; Seabed; Antarctic Intermediate Water

THE basic pattern of bottom water circulation in the Atlantic Ocean was well described in the reports of the Meteor Expedition1. On the basis of dynamic topography, Wust2 calculated average current velocities of 2–15 cm/sec for the axis of the northward flowing Antarctic Bottom Current in the South Atlantic. These velocities, considered high by some workers, met with some scepticism3, but recent direct current measurements in similar current systems indicate velocities of the same magnitude4. In the South Atlantic, a good correlation is observed5 between the occurrence of ripple and scour marks and the location of the Antarctic Bottom Current as determined by Wust. Recently, Heezen, Hollister and Ruddiman6 observed strong scour and other effects of bottom currents6 on the continental rise and Blake-Bahama Outer Ridge7. They inferred6 that geostrophic ‘contour’ currents in the deep sea are not only effective in transporting sediments, but constitute one of the principal agents in the shaping of the great sediment bodies of the continental margins8. These conclusions were based on an investigation of oriented bottom photographs, sediment cores and echograms. We have extended this study to the Antarctic Bottom Current and its effects on the Bermuda Rise.