Millennial-scale propagation of Atlantic deep waters to the glacial Southern Ocean

• Published in: Paleoceanography
• Main Authors: Kissel, Catherine, Laj, Carlo, Piotrowski, Alexander, Goldstein, Steven, Hemming, Sidney
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Climat et Magnétisme (CLIMAG), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Greenland; Southern Ocean; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-03192906; https://hal.archives-ouvertes.fr/hal-03192906/document; https://hal.archives-ouvertes.fr/hal-03192906/file/2008PA001624.pdf; https://doi.org/10.1029/2008PA001624

International audience The compilation of changes in the magnetic properties at various sites distributed along the path of the deepwater mass in North Atlantic shows large-amplitude short-term fluctuations reflecting changes in the strength of the North Atlantic Deep Water (NADW). These changes, which suggest a two-mode deep glacial circulation dynamic, are perfectly concurrent with air temperature changes over Greenland. They also share a similar pattern with those reported in the Nd isotope ratios from the deep Cape Basin during the same time period. Greenland interstadials were accompanied by increased flow speed of NADW and relatively more NADW reaching the Southern Ocean, while during Greenland stadials and Heinrich events, both the North Atlantic flow speed of NADW and its presence in the South Atlantic were reduced. It is demonstrated that both proxies are tracing the same water mass, and their reliability for monitoring changes in the deepwater circulation is therefore clearly established. After using the climatically independent geomagnetic assisted stratigraphy to put the Northern and Southern Hemisphere records on the same age scale, the South Atlantic record appears to lag changes in North Atlantic flow speeds by approximately 860 ± 220 years during the most prominent and best defined cycles (interstadials 12 and 8). Although future work is needed, this significant offset provides a first observation and tentative quantification of the time needed for glacial northern component water to mix downward and to flow from the North to the South Atlantic.