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Gherardi, Jeanne Marie; Labeyrie, L.; Nave, S.; Francois, R.; Mcmanus, J. F.; Cortijo, E.. |
Studies from the subtropical western and eastern Atlantic Ocean, using the Pa-231/Th-230 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 Pa-231/Th-230 records from North Atlantic cores between 1710 and 4550 m water depth. Comparing sedimentary Pa-231/Th-230 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 Pa-231/Th-230 ratio measured in upper Holocene sediments indicates slow water renewal above similar to 2500 m and... |
Tipo: Text |
Palavras-chave: MOC; North Atlantic; Deglaciation; 231Pa/230Th. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00233/34468/32855.pdf |
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Lippold, Jorg; Gherardi, Jeanne Marie; Luo, Yiming. |
Variations of the Atlantic Meridional Overturning Circulation (AMOC) are believed to have crucially influenced Earth's climate due to its key role in the inter-hemispheric redistribution of heat and carbon. To assess its past strength, the sedimentary Pa-231/Th-230 proxy has been developed and improved but also contested due to its sensitivity to other factors beyond ocean circulation. In order to provide a better basis for the understanding of the Atlantic Pa-231/Th-230 system, and therefore to shed light on the controversy, we compare new measurements of Holocene sediments from the north Brazilian margin to water column data and the output of a two-dimensional scavenging-circulation model, based on modern circulation patterns and reversible scavenging... |
Tipo: Text |
Palavras-chave: 231Pa/230Th; Atlantic Meridional Overturning Circulation; Holocene; Deep sea sediments. |
Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00215/32576/31045.pdf |
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