Paleocurrents in the Charlie-Gibbs Fracture Zoneduring the Late Quaternary
Planktonic foraminiferal and ice-rafted debris counts data, as well as mean size of mineral particles of 10- 63 |jm fraction (“sortable silt” - SS) were used as proxy for surface and near-bottom paleocurrents intensity variations. Data obtained support our hypothesis about turbiditic origin of the lower (80-370 cm) section of studied AMK-4515 core. Stratigraphic subdivision of the upper section (0-80 cm) allows to allocate 2 marine isotope stages (MIS) covering the last 27 ka. The main intervals of the North Atlantic Polar Front (PF) were registered: southern compare to modern PF position - early MIS 2 (24-27 ka); PF presence in the study area - MIS 2 (20-24 ka); southern compare to study area position of Pf - last glacial maximum (18- 20 ka). Influence of the near-bottom currents within the investigated interval led to beginning of the channel-related drift formation on the northern slope of the southern channel of the Charlie-Gibbs Fracture Zone. There is a weak relationship between near-bottom contour currents intensity and long-term climatic cyclicity. However, intervals corresponding to Heinrich events coincide with decreasing of bottom currents activity.