Millennial-scale Holocene hydrological changes in the northeast Atlantic: New insights from ‘ La Grande Vasière ’ mid-shelf mud belt

Type Article
Date 2019-03
Language English
Author(s) Mojtahid Meryem1, Durand Matthieu1, Coste Pierre-Olivier1, 2, Toucanne SamuelORCID3, Howa Hélène1, Nizou Jean3, Eynaud Frédérique4, Penaud Aurélie2
Affiliation(s) 1 : LPG-BIAF, UMR-CNRS 6112, University of Angers, France
2 : University of Brest and Laboratoire Géosciences Océan, CNRS UMR 6538, Institut Universitaire Européen de la Mer, France
3 : Laboratoire Géodynamique et enregistrement Sédimentaire, IFREMER, France
4 : UMR CNRS 5805 EPOC (Environnements et Paléoenvironnements Océaniques et Continentaux), University of Bordeaux, France
Source Holocene (0959-6836) (SAGE Publications), 2019-03 , Vol. 29 , N. 3 , P. 467-480
DOI 10.1177/0959683618816478
WOS© Times Cited 7
Keyword(s) AMOC, Bay of Biscay, benthic foraminifera, NAO-like process, river runoff, stable isotopes

A mid- to late-Holocene paleohydrological reconstruction from the northeast Atlantic is proposed through the study of a high-resolution sedimentary record from the northern continental shelf of the Bay of Biscay (BoB). Three foraminiferal species dominate the assemblages with Rosalina globularis showing an overall decrease in absolute and relative abundances from ~7 to 0.4 cal. ka BP, whereas the opposite trend is observed for Cibicides refulgens and Lobatula. These long-term patterns are interpreted as a response to the overall cooling trend and/or the progressive deepening of the water column because of the relative sea-level (RSL) rise. Foraminiferal δ18O and grain-size analyses show a significant shift around 3.5–2.5 cal. ka BP toward a heavier isotopic signature and finer sediments. We mainly link this change to enhanced contribution of continental freshwaters and fine sediments after the near-stabilization of the RSL rise. By reducing coastal accommodation spaces, this led to a better channelization of river outflows and probably to the formation of the modern winter thermohaline front. Superimposed on these long-term patterns, our data highlight strong millennial-scale variability (1250-year peak). Such cyclicity is consistent with several records tracing changes in rainfall and storminess regimes in northern Europe, and the dynamics of the subpolar gyre (SPG). We suggest a millennial time-scale control of a NAO-like (North Atlantic Oscillation) climatic process modulating continental humidity (and the associated river discharges) and SPG dynamics through wind stress. Spectral analyses reveal an additional 500-year frequency peak implying a possible solar forcing.

Full Text
File Pages Size Access
Publisher's official version 14 2 MB Open access
Supplemental Material 15 3 MB Open access
Top of the page

How to cite 

Mojtahid Meryem, Durand Matthieu, Coste Pierre-Olivier, Toucanne Samuel, Howa Hélène, Nizou Jean, Eynaud Frédérique, Penaud Aurélie (2019). Millennial-scale Holocene hydrological changes in the northeast Atlantic: New insights from ‘ La Grande Vasière ’ mid-shelf mud belt. Holocene, 29(3), 467-480. Publisher's official version : , Open Access version :