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dc.contributor.authorGherardi, J.‐M.  Concept link
dc.contributor.authorLabeyrie, L.  Concept link
dc.contributor.authorNave, Silvia  Concept link
dc.contributor.authorFrancois, Roger  Concept link
dc.contributor.authorMcManus, Jerry F.  Concept link
dc.contributor.authorCortijo, E.  Concept link
dc.date.accessioned2010-05-18T14:53:05Z
dc.date.available2010-05-18T14:53:05Z
dc.date.issued2009-05-02
dc.identifier.citationPaleoceanography 24 (2009): PA2204en_US
dc.identifier.urihttps://hdl.handle.net/1912/3463
dc.descriptionAuthor Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA2204, doi:10.1029/2008PA001696.en_US
dc.description.abstractStudies from the subtropical western and eastern Atlantic Ocean, using the 231Pa/230Th ratio as a kinematic proxy for deep water circulation, provided compelling evidence for a strong link between climate and the rate of meridional overturning circulation (MOC) over the last deglaciation. In this study, we present a compilation of existing and new sedimentary 231Pa/230Th records from North Atlantic cores between 1710 and 4550 m water depth. Comparing sedimentary 231Pa/230Th from different depths provides new insights into the evolution of the geometry and rate of deep water formation in the North Atlantic during the last 20,000 years. The 231Pa/230Th ratio measured in upper Holocene sediments indicates slow water renewal above ∼2500 m and rapid flushing below, consistent with our understanding of modern circulation. In contrast, during the Last Glacial Maximum (LGM), Glacial North Atlantic Intermediate Water (GNAIW) drove a rapid overturning circulation to a depth of at least ∼3000 m depth. Below ∼4000 m, water renewal was much slower than today. At the onset of Heinrich event 1, transport by the overturning circulation declined at all depths. GNAIW shoaled above 3000 m and significantly weakened but did not totally shut down. During the Bølling‐Allerød (BA) that followed, water renewal rates further decreased above 2000 m but increased below. Our results suggest for the first time that ocean circulation during that period was quite distinct from the modern circulation mode, with a comparatively higher renewal rate above 3000 m and a lower renewal rate below in a pattern similar to the LGM but less accentuated. MOC during the Younger Dryas appears very similar to BA down to 2000 m and slightly slower below.en_US
dc.description.sponsorshipThe LSCE-WHOI cooperation has been supported by a NSF-CNRS cooperative grant NSF INT-0233483. Analytical measurements in LSCE have been supported by French Programme National d’Etude de la Dynamique du Climat, Commissariat a` l’Energie Atomique, and Centre National de la Recherche Scientifique. The participation of J.F.M. in this project was supported in part by grants from the U.S.-NSF, WHOI-OCCI, and the Gary Comer Science and Education Foundation. R.F.’s participation was supported by grants from NSERC and the Canadian Foundation for Climate and Atmospheric Science.en_US
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.format.mimetypeapplication/vnd.ms-excel
dc.format.mimetypeapplication/postscript
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2008PA001696
dc.subjectMOCen_US
dc.titleGlacial‐interglacial circulation changes inferred from 231Pa/230Th sedimentary record in the North Atlantic region
dc.typeArticle
dc.identifier.doi10.1029/2008PA001696


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