Sortable silt paleo-current proxies of sediment core GeoB13862-1 from the Southwest Atlantic

Antarctic Intermediate Water (AAIW) is an essential component of the Atlantic meridional overturning circulation (AMOC) contributing to balance the southward flow of North Atlantic Deep Water (NADW). However, the role of AAIW in Holocene abrupt climate changes remains poorly understood. Here we reco...

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Bibliographic Details
Main Authors: Voigt, Ines, Chiessi, Cristiano Mazur, Piola, Alberto R, Henrich, Rüdiger
Format: Dataset
Language:English
Published: PANGAEA 2016
Subjects:
496
AGE
Beckman Coulter Laser diffraction particle size analyzer LS 13 320
Center for Marine Environmental Sciences
DEPTH
sediment/rock
GC
GeoB13862-1
Gravity corer
M78/3B
MARUM
Meteor (1986)
Silt/clay ratio
Size fraction 0.063-0.010 mm
sortable silt
Sortable-silt mean
Antarc*
Antarctic
NADW
North Atlantic Deep Water
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.873264
https://doi.org/10.1594/PANGAEA.873264
Description
Summary:Antarctic Intermediate Water (AAIW) is an essential component of the Atlantic meridional overturning circulation (AMOC) contributing to balance the southward flow of North Atlantic Deep Water (NADW). However, the role of AAIW in Holocene abrupt climate changes remains poorly understood. Here we reconstruct changes in the flow strength of AAIW based on a high temporal resolution paleocurrent record from the Southwest Atlantic. Superimposed on a slight increase in AAIW strength at ~ 7 ka BP, a succession of millennial-scale AAIW variations is recognized in our paleocurrent records indicating a highly variable intermediate water circulation throughout the Holocene. Although variations in the strength and position of the Southern Westerlies Winds (SWW) are proposed to greatly influence the formation and circulation of AAIW, we cannot confirm such a potential SWW-AAIW linkage since our records of AAIW flow strength do not correlate to Holocene shifts of the SWW across the Atlantic. However, our data shows a good correspondence with abrupt variations in the AMOC with enhanced (reduced) northward advection of AAIW during periods of reduced (enhanced) NADW circulation. These results provide evidence for a Holocene AAIW-NADW see-saw. Thus, although the exact forcing mechanism remains unresolved, we suggest that Holocene perturbations in AAIW exerted a significant impact on the AMOC.

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