Holocene evolution of deep circulation in the northern North Atlantic traced by Sm, Nd and Pb isotopes and bulk sediment mineralogy

• Published in: Paleoceanography
• Main Authors: Fagel, Nathalie, Mattielli, Nadine
• Other Authors: Geosciences, Mare
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2011
• Subjects: Radiogenic isotope geochemistry; Marine sediments; Geochemical tracers; Atlantic Ocean; deep oceanic circulation; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Norwegian Sea; Iceland; Labrador Sea; North Atlantic Deep Water; North Atlantic
• Online Access: https://orbi.uliege.be/handle/2268/102411; https://doi.org/10.1029/2011PA002168

peer reviewed Bulk mineralogy, Sm, Nd and Pb elemental and isotopic compositions of the clay-size fraction of Holocene sediments were analysed in 3 deep North Atlantic cores to trace the particle provenance. The aims of the present paper are to identify the origin of the particles driven by deep currents and to reconstruct deep circulation changes over the Holocene in the North Atlantic. The three cores are retrieved in fracture zones; two of them are located in the Island Basin along the gyre of North Atlantic Deep Water, and the third core is located off the present deep circulation gyre in the Labrador Sea. Whereas sedimentary supplies in the Labrador Sea were constantly derived from proximal sources, the geochemical mixing trends in the Iceland Basin samples indicate pronounced changes in the relative contribution of continental margin inputs over the past 6 kyr. Supplies from Western European margin that sharply increased at 6 kyr were progressively diluted by a larger contribution of Scandinavian margins over the last 3 kyr. Changes in composition of the particles imply significant reorganisation of paleocirculation of the deep North Atlantic components in the Eastern basins: mainly reorganisations for both Iceland-Scotland Overflow Water (ISOW) and Norwegian Sea Overflow Water (NSOW). Moreover the unusual Bulk mineralogy, Sm, Nd and Pb elemental and isotopic compositions of the clay-size fraction of Holocene sediments were analysed in 3 deep North Atlantic cores to trace the particle provenance. The aims of the present paper are to identify the origin of the particles driven by deep currents and to reconstruct deep circulation changes over the Holocene in the North Atlantic. The three cores are retrieved in fracture zones; two of them are located in the Island Basin along the gyre of North Atlantic Deep Water, and the third core is located off the present deep circulation gyre in the Labrador Sea. Whereas sedimentary supplies in the Labrador Sea were constantly derived from proximal sources, the ...