Holocene changes in North-East Atlantic sea surface hysdrology derived from cold-water corals
Mélanie Douarin  1@  , Quentin Dubois-Dauphin  2@  , Mary Elliot  1@  , Edwige Pons-Branchu  3@  , Christophe Colin  2@  , Dominique Blamart  4@  , David Long  5@  
1 : Laboratoire de Planétologie et Géodynamique de Nantes  (LPGN)
CNRS : UMR6112, INSU, Université de Nantes
2 Rue de la Houssinière - BP 92208 44322 NANTES CEDEX 3 -  France
2 : Géosciences Paris-Sud  (GEOPS)  -  Site web
Université Paris Sud - Paris XI, CNRS : UMR8148
Laboratoire Géosciences Paris-Sud (GEOPS), UMR 8148, CNRS-Université de Paris-Sud, Bâtiment 504, 91405 Orsay Cedex, France. -  France
3 : Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]  (LSCE - UMR 8212)  -  Site web
Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), CEA, CNRS : UMR8212
LSCE-CEA-Orme des Merisiers (point courrier 129) F-91191 GIF-SUR-YVETTE CEDEX LSCE-Vallée Bât. 12, avenue de la Terrasse, F-91198 GIF-SUR-YVETTE CEDEX -  France
4 : Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]  (LSCE)  -  Site web
Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), CEA, CNRS : UMR8212
LSCE-CEA-Orme des Merisiers (point courrier 129) F-91191 GIF-SUR-YVETTE CEDEX LSCE-Vallée Bât. 12, avenue de la Terrasse, F-91198 GIF-SUR-YVETTE CEDEX -  France
5 : British Geological Survey  (BGS)
Murchison House, West Mains Road, Edinburgh EH9 3LA -  Royaume-Uni

Changes in Holocene sea surface hydrology have been derived from a coral rich sediment core collected in the northeast Atlantic (BGS core 59-07/293, 59°43N; 06°29W, 282 m water depth). The downcore L. pertusa U-series chronology, which covers most of the Holocene period with a centennial temporal resolution, have been coupled with neodymium isotope measurements to document sea surface hydrology changes and more specifically the relative influence of subpolar and subtropical gyre (SPG and STG) waters to the study site. Large variations on the neodymium isotopic composition (eNd), with values ranging from -16.6 to -10.2 were documented, with a major transition between 5 ka and 6 ka. eNd values centred at -14.5 for the period from 8.2 ka to 6 ka suggest an enhanced east-west SPG elongation and strong outgrowth of Labrador Sea waters into the eastern Atlantic. In contrast, eNd values are centred at -12.5 during the period comprised between 2.1 ka and 5 ka suggesting a weaker influenced of SPG waters. Superimposed on this major feature, large shifts in eNd values are also reported highlighting potential abrupt hydrological changes that could be associated with Holocene climatic anomalies. Finally, at 2.1 ka there is a major shift with less negative eNd values, which appears correlated with the apparent demise of coral on that site. 


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