Down-core sedimentary Sr-Nd isotope records from two Cape Basin sediment cores in the South Atlantic: GeoB3603-2 (Meteor cruise M34/1) and MD02-2594 (Marion Dufresne cruise MD128)

We report down-core sedimentary Nd isotope (epsilon Nd) records from two South Atlantic sediment cores, MD02-2594 and GeoB3603-2, located on the western South African continental margin. The core sites are positioned downstream of the present-day flow path of North Atlantic Deep Water (NADW) and close to the Southern Ocean, which makes them suitable for reconstructing past variability in NADW circulation over the last glacial cycle. The Fe-Mn leachates epsilon Nd records show a coherent decreasing trend from glacial radiogenic values towards less radiogenic values during the Holocene. This trend is confirmed by epsilon Nd in fish debris and mixed planktonic foraminifera, albeit with an offset during the Holocene to lower values relative to the leachates, matching the present-day composition of NADW in the Cape Basin. We interpret the epsilon Nd changes as reflecting the glacial shoaling of Southern Ocean waters to shallower depths combined with the admixing of southward flowing Northern Component Water (NCW). A compilation of Atlantic epsilon Nd records reveals increasing radiogenic isotope signatures towards the south and with increasing depth. This signal is most prominent during the Last Glacial Maximum (LGM) and of similar amplitude across the Atlantic basin, suggesting continuous deep water production in the North Atlantic and export to the South Atlantic and the Southern Ocean. The amplitude of the epsilon Nd change from the LGM to Holocene is largest in the southernmost cores, implying a greater sensitivity to the deglacial strengthening of NADW at these sites. This signal impacted most prominently the South Atlantic deep and bottom water layers that were particularly deprived of NCW during the LGM. The epsilon Nd variations correlate with changes in 231Pa/230Th ratios and benthic d13C across the deglacial transition. Together with the contrasting 231Pa/230Th: epsilon Nd pattern of the North and South Atlantic, this indicates a progressive reorganization of the AMOC to full strength during the Holocene.

Data and Resources

This dataset has no data

Cite this as

Wei, Ran, Abouchami, Wafa, Zahn, Rainer, Masqué, Pere (2016). Dataset: Down-core sedimentary Sr-Nd isotope records from two Cape Basin sediment cores in the South Atlantic: GeoB3603-2 (Meteor cruise M34/1) and MD02-2594 (Marion Dufresne cruise MD128). https://doi.org/10.1594/PANGAEA.858244

DOI retrieved: 2016

Additional Info

Field Value
Imported on November 29, 2024
Last update November 29, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.858244
Author Wei, Ran
Given Name Ran
Family Name Wei
More Authors
Abouchami, Wafa
Zahn, Rainer
Masqué, Pere
Source Creation 2016
Publication Year 2016
Resource Type application/zip - filename: Wei_2016
Subject Areas
Name: Geophysics

Related Identifiers
Title: Deep circulation changes in the South Atlantic since the Last Glacial Maximum from Nd isotope and multi-proxy records
Identifier: https://doi.org/10.1016/j.epsl.2015.11.001
Type: DOI
Relation: IsSupplementTo
Year: 2016
Source: Earth and Planetary Science Letters
Authors: Wei Ran , Abouchami Wafa , Zahn Rainer , Masqué Pere .