Position of the Polar Front along the western Iberian margin during key cold episodes of the last 45 ka

Type Article
Date 2009-07-01
Language English
Author(s) Eynaud Frederique1, de Abreu Lucia2, 3, Voelker Antje2, 3, Schoenfeld Joachim4, Salgueiro Emilia2, 3, Turon Jean-Louis1, Penaud Aurelie1, Toucanne Samuel1, Naughton Filipa2, Goni Maria Fernanda Sanchez1, Malaize Bruno1, Cacho Isabel5
Affiliation(s) 1 : Univ Bordeaux 1, EPOC, UMR 5805, F-33405 Talence, France.
2 : LNEG, Dept Geol Marinha, P-2721866 Zambujal, Portugal.
3 : CIMAR Associate Lab, P-4050123 Oporto, Portugal.
4 : Univ Kiel, Leibniz Inst Marine Sci, IFM, GEOMAR, D-24148 Kiel, Germany.
5 : Univ Barcelona, Fac Geol, Dept Estratig Paleontol & Geociencies Marines, E-08028 Barcelona, Spain.
Source Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2009-07-01 , Vol. 10 , N. 7 , P. 1-21
DOI 10.1029/2009GC002398
WOS© Times Cited 130
Keyword(s) Polar Front, LGM, Heinrich events
Abstract This paper documents the migration of the Polar Front (PF) over the Iberian margin during some of the cold climatic extremes of the last 45 ka. It is based on a compilation of robust and coherent paleohydrological proxies obtained from eleven cores distributed between 36 and 42 degrees N. Planktonic delta O-18 (Globigerina bulloides), ice-rafted detritus concentrations, and the relative abundance of the polar foraminifera Neogloboquadrina pachyderma sinistral were used to track the PF position. These three data sets, compared from core to core, show a consistent evolution of the sea surface paleohydrology along the Iberian margin over the last 45 ka. We focused on five time slices representative of cold periods under distinct paleoenvironmental forcings: the 8.2 ka event and the Younger Dryas (two recent cold events occurring within high values of summer insolation), Heinrich events 1 and 4 (reflecting major episodes of massive iceberg discharges into the North Atlantic), and the Last Glacial Maximum (typifying the highest ice volume accumulated in the Northern Hemisphere). For each event, we generated schematic maps mirroring past sea surface hydrological conditions. The maps revealed that the Polar Front presence along the Iberian margin was restricted to Heinrich events. The sea surface conditions during the Last Glacial Maximum were close to those at present day, except for the northern sites which briefly experienced subarctic conditions.
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Eynaud Frederique, de Abreu Lucia, Voelker Antje, Schoenfeld Joachim, Salgueiro Emilia, Turon Jean-Louis, Penaud Aurelie, Toucanne Samuel, Naughton Filipa, Goni Maria Fernanda Sanchez, Malaize Bruno, Cacho Isabel (2009). Position of the Polar Front along the western Iberian margin during key cold episodes of the last 45 ka. Geochemistry Geophysics Geosystems, 10(7), 1-21. Publisher's official version : https://doi.org/10.1029/2009GC002398 , Open Access version : https://archimer.ifremer.fr/doc/00218/32909/