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

Abstract

Was reconstructed deep-sea water circulation near the Hunter Channel (Rio Grande Rise – South-West Atlantic) in a late Pleistocene and Holocene (MIS 4-MIS 1) by benthonic foraminifera. Was studied three cores of bottom sediment. Now moves the upper North Atlantic deep water (NADW) through the Hunter Channel from the North to the South. The lower NADW in the same direction came in MIS 2 and in MIS 4. There was the lower Circumpolar deep water (CPDW), NADW and Antarctic bottom water (AnBW) in MIS 3 periodically. CPDW prevail in a near bottom layer and in Holocene and in the late Pleistocene before the Hunter Channel sidewise the Argentine Basin. So in the Hunter Channel and on the way to it from south side for all studied period AnBW was almost not. Dissolution of carbonates during the Holocene happens in the deepest east part of the Hunter Channel. In Ice Ages processes of dissolution amplified and affected east part of the channel. Dissolution happen and happened not at the expense of AnBW, and at the expense of NADW which becomes there aggressive in relation to a calcium carbonate.