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Trends and centennial-scale variability of surface water temperatures in the North Atlantic during the Holocene

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  • Marie Alexandrine Sicre, Sorbonne Université
  • ,
  • Bassem Jalali, Sorbonne Université, State Oceanic Administration China
  • ,
  • Jón Eiríksson, Earth Science Institute, University of Iceland, University of Iceland
  • ,
  • Karen Luise Knudsen
  • Vincent Klein, Sorbonne Université
  • ,
  • Violaine Pellichero, Sorbonne Université

Two sediment cores retrieved off North Iceland (western Nordic Seas) and on the eastern flank of Reykjanes Ridge (Iceland Basin) were analyzed to generate high-resolution alkenone-derived sea surface temperature (SST) records to investigate North Atlantic Ocean circulation changes during the Holocene. Early Holocene SSTs off North Iceland were unstable (10 ± 1 °C) and 3 °C warmer than today reflecting active northward heat transport of the Atlantic Meridional Overturning Circulation (AMOC) interrupted by intermittent Polar Waters incursions onto the North Icelandic shelf. The Holocene thermal optimum occurred synchronously east of Reykjanes Ridge, with a mean value of 11.5 °C (±0.5 °C) similar to today, consistent with a sustained influence of AMOC. Both records indicate that the circulation across the North Atlantic intensified between 8000 and 7000 yr BP. Thereafter, SSTs in the two basin sites broadly depict opposing trends and centennial-scale oscillations and a notable cooling at ∼5300 yr BP that coincides with Bond 4 event and the temporary collapse of the deep-water circulation. From 2500 yr BP onwards, SSTs in the Iceland Basin and the western Nordic Seas diverge leading to a marked cooling/warming dipole resulting in a temperature difference today of 4.5 °C. We show that SST trends and centennial-scale variability reflect variations of the subpolar gyre (SPG) circulation linked to drifting ice events and convection changes in the Labrador and Nordic Seas.

OriginalsprogEngelsk
Artikelnummer107033
TidsskriftQuaternary Science Reviews
Vol/bind265
ISSN0277-3791
DOI
StatusUdgivet - aug. 2021

Bibliografisk note

Funding Information:
This work was supported by the PACTHOL project of the French National program LEFE (Les Enveloppes Fluides et l’Environnement) of INSU/ CNRS and the French National Research Agency HAMOC project ( ANR-13-BS06- 0003 ). We thank the Centre National de la Recherche Scientifique ( CNRS ) for salary support of MAS and VK. Both cores have been obtained during cruises conducted aboard the French R/V Marion Dufresne in the framework of the International Marine Past Global Change Study (IMAGES) program. The authors thank the crew and scientists of the R/V Marion Dufresne involved in the coring operations.

Funding Information:
This work was supported by the PACTHOL project of the French National program LEFE (Les Enveloppes Fluides et l'Environnement) of INSU/CNRS and the French National Research Agency HAMOC project (ANR-13-BS06- 0003). We thank the Centre National de la Recherche Scientifique (CNRS) for salary support of MAS and VK. Both cores have been obtained during cruises conducted aboard the French R/V Marion Dufresne in the framework of the International Marine Past Global Change Study (IMAGES) program. The authors thank the crew and scientists of the R/V Marion Dufresne involved in the coring operations.

Publisher Copyright:
© 2021

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