Strontium isotopes, ages and carbonate content of sediments from the Agulhas Current

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Hauptverfasser: Franzese, Allison M, Hemming, Sidney R, Goldstein, Steven L
Format: Dataset Open Access
Sprache:en
Veröffentlicht: PANGAEA 2009
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author Franzese, Allison M
Hemming, Sidney R
Goldstein, Steven L
author_facet Franzese, Allison M
Hemming, Sidney R
Goldstein, Steven L
collection Datos científicos de ciencias marinas y ambientales
contents The Agulhas Leakage represents a significant portion of the warm, surface return flow of the global overturning circulation and thus may be an important feedback in the ocean climate system. Models indicate that reduced leakage could be caused by a stronger Agulhas Current and/or a more upstream (eastward) Agulhas Retroflection, while a weaker Agulhas Current would result in a more westward retroflection and increased leakage. However, data for the Last Glacial Maximum support both a weaker Agulhas Current and less leakage, implying a possible displacement of the retroflection. We present new 87Sr/86Sr results for modern sediments within this region, confirming that the modern pathway of the Agulhas Current, Retroflection, and Leakage can be traced by terrigenous sediment provenance using Sr isotopes. New 87Sr/86Sr data from sediments deposited during the Last Glacial Maximum suggest that the glacial Agulhas Current and Retroflection followed nearly their modern trajectory. The provenance data appear to rule out both a stronger Agulhas Current and a more upstream Agulhas Retroflection. We conclude that the reduced glacial leakage was caused by the weakened Agulhas Current, with no significant change in the retroflection position. This is inconsistent with the model predictions and thus emphasizes the need for further work in this region.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_832064
institution PANGAEA
language en
publishDate 2009
publisher PANGAEA
record_format pangaea
spellingShingle Strontium isotopes, ages and carbonate content of sediments from the Agulhas Current
Franzese, Allison M
Hemming, Sidney R
Goldstein, Steven L

The Agulhas Leakage represents a significant portion of the warm, surface return flow of the global overturning circulation and thus may be an important feedback in the ocean climate system. Models indicate that reduced leakage could be caused by a stronger Agulhas Current and/or a more upstream (eastward) Agulhas Retroflection, while a weaker Agulhas Current would result in a more westward retroflection and increased leakage. However, data for the Last Glacial Maximum support both a weaker Agulhas Current and less leakage, implying a possible displacement of the retroflection. We present new 87Sr/86Sr results for modern sediments within this region, confirming that the modern pathway of the Agulhas Current, Retroflection, and Leakage can be traced by terrigenous sediment provenance using Sr isotopes. New 87Sr/86Sr data from sediments deposited during the Last Glacial Maximum suggest that the glacial Agulhas Current and Retroflection followed nearly their modern trajectory. The provenance data appear to rule out both a stronger Agulhas Current and a more upstream Agulhas Retroflection. We conclude that the reduced glacial leakage was caused by the weakened Agulhas Current, with no significant change in the retroflection position. This is inconsistent with the model predictions and thus emphasizes the need for further work in this region.
title Strontium isotopes, ages and carbonate content of sediments from the Agulhas Current
topic
url https://doi.org/10.1594/PANGAEA.832064