Deep-Water Circulation in the Hunter Channel (Southwest Atlantic) in the Late Pleistocene and Holocene Based on Benthic Foraminifera

Resumo

Based on benthic foraminifera from three sediment cores, the deep-water circulation near the Hunter Channel (Southwest Atlantic) in the Late Pleistocene and Holocene has been reconstructed (marine isotope stages (MIS) 4–1). Today, the North Atlantic Deep Water (NADW) moves through the Hunter Channel from north to south. At MIS 2 and 4, lower NADW flowed in the same direction. At MIS 3, NADW, Antarctic Bottom Water (AABW), and Lower Circumpolar Deep Water (LCDW) periodically appeared in the Hunter Channel. On the approach to the Hunter Channel from the Argentine Basin, there are no AABW signatures in the Late Pleistocene or Holocene. In the Holocene, carbonates dissolved in the deeper eastern part of the Hunter channel. During glaciations, dissolution processes intensified and also reached the western part of the channel. Dissolution proceeded and continues to proceed not because of AABW but NADW, which becomes aggressive here toward calcium carbonate.