Glacial deep water geometry: South Atlantic benthic foraminiferal Cd/Ca and delta C-13 evidence

A depth transect of cores from 1268 to 3909 m water depth in the western So uth Atlantic are ideally situated to monitor the interocean exchange of dee p water and variations in the relative strength of northern and southern so urces of deep water production. Benthic foraminiferal Cd/Ca and delta(13)C data suggest that Glacial North Atlantic Intermediate Water (GNAIW) extende d at least as far south as 28 degrees S in the western South Atlantic. The core of nutrient-depleted water was situated at similar to 1500 m, above an d below water masses with higher nutrient concentrations. When examined in conjunction with published paired Cd/Ca and delta(13)C from intermediate de pth cores from other basins, it appears that the extent of GNAIW influence on the intermediate waters of the world's oceans was less than suggested pr eviously. Differentiating among possible pathways for the glacial deep ocea n (> 3 km) requires a better understanding of the controls on Cd/Ca and del ta(13)C values of benthic foraminifera.