Resumen de Holocene bottom current variability at Feni Drift, NE Atlantic Ocean and wider paleoclimatic implications
Thomas Richter, Henk de Haas, Henko de Stigter, Tjeerd C.E. van Weering
A high-resolution Holocene sediment record from Feni Drift (NE Atlantic Ocean) was investigated for terrigenous sortable silt mean size tracing relative bottom current strength. Grain-size data imply gradually decreasing bottom current strength at the onset of the Holocene culminating in a broad 10-8ka flow speed minimum, a sustained early mid-Holocene thermohaline intensity maximum and subsequent general waning of bottom currents with pronounced centennial- to millennial-scale variability. Weaker and/or more variable bottom current strength coincides with higher depositional fluxes of both carbonate and non-carbonate components. The early Holocene flow speed minimum is ascribed to the ongoing influence of remnant ice sheets around the North Atlantic. For the remainder of the record, thermohaline circulation variability can be related to decreasing northern hemispheric summer insolation and slight climatic deterioration. Pronounced shifts in the grain-size record at 5.5 and 3.4 ka coincide with evidence from other locations for stepwise decreases in the intensity of the North Atlantic current and related reduced northward heat transport, indicating a link between bottom current flow strength and regional climate.
