Géochimie isotopique Sr-Nd-Pb des sédiments accumulés depuis 700 000 ans le long de la dorsale de Reykjanes (58-60ʻ Nord) /

Hantchi, Karimou Dia

doi:10.1522/18320272

Cited by 2 publications

(6 citation statements)

References 105 publications

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“…This allows comparisons between the different tracers and allows the detection of the main trends within the sedimentary sequence. For example, in order to test the insensitivity of neodymium to contamination of seawater, controlled attacks have been attempted on some subsamples of box-cores by partially dissolving the sample using hydrochloric acid (0.275 N HCl; Dia Hantchi, 2000). The lead was separated and purified on an ion exchange resin from an aliquot powder solution of 20 to 70 mg of dry sediment.…”

Section: Methodsmentioning

confidence: 99%

“…This dilution would be exacerbated in the sediments of the western flank by a greater production of biogenic carbonates in this area. As, the CaCO3 content fluctuates around circa 28-46 % in the eastern flank of the Reykjanes Ridge (Savkina & al., 2018), circa 10-45 % along the axial zone and 20-80 % in the western flank of the ridge (Dia Hantchi, 2000).…”

Section: Differential Dilution Of Terrigenous Inputs By Biogenic Carbonates Vs Mixing Process Between Mantle and Crustal Materialsmentioning

confidence: 99%

“…The correspondence with the average regional rocks (Fagel & al., 2014), the very existence of a population of tholeiites poor in Light Rare Earth Elements (LREE) in the axial region (Dia Hantchi, 2000).…”

Section: Differential Dilution Of Terrigenous Inputs By Biogenic Carbonates Vs Mixing Process Between Mantle and Crustal Materialsmentioning

confidence: 99%

“…As can be seen from Figure 8, the sediments of the three box-cores are for the most part located in a domain framed by the Icelandic poles and three acid poles (Arctic, Greenland and Baltic; Dia Hantchi, 2000):  Thereby samples belonging to the summit slices define a new alignment, can be interpreted as reflecting a process of mixing between differentiated elements of Iceland, the ridge and the clearly dominant Arctic pole. …”

Section: Main Driving Mechanism Of the Mantle Componentsmentioning

confidence: 99%

“…Thanks to its position as a mid-Atlantic dorsal island, Iceland would play a leading role in this Great Global Conveyor Belt, which partially control the climate of the North Atlantic (Curry & Mauritzen, 2005;Buckley & Marshall, 2016). While the mid-oceanic ridge of Reykjanes in southern Iceland, by its morphotectonic characteristics, strongly influences the direction, flow and chemistry of the water bodies displaced by this global thermohaline circulation (Dia Hantchi, 2000;Chafik & al., 2014). Moreover, finestructure and microstructure full-depth vertical profiles collected along the Reykjanes Ridge though the flank is known to have strong turbulent mixing (Ferron & al., 2014).…”

Section: Introductionmentioning

confidence: 99%

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Impacts of Deep Water Structuring on Seabed Pollution Levels: Evidence from Radiogenic Isotopes (Pb-Sr-Nd) in Surface Sediments Along the Reykjanes Ridge (Southern Iceland)

Karimou

Konaté

Ali

et al. 2019

ESJ

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Significant proportions of debris containing pollutants are present in remote and unknown areas of the deep seabed. Although identified amongst the top threats to marine ecosystem and human health, the mechanisms that particulate materials entered rapidly these deep ocean systems are still matter of debate. This study use depicting radiogenic isotopes (Sr, Nd, Pb) to question the relationship between the seabed sediment contamination levels and ambient stratification in the North Atlantic Ocean. On this basis, we studied sedimentary inputs and related mechanisms from more recent sequences collected at three locations representing different deep-sea hydrodynamics along the Reykjanes Ridge. Sm-Nd concentrations, as well as Sm-Nd-Sr-Pb isotopic compositions, were determined in digested and purified fraction of the sediment cores by Thermal Ionization Mass Spectrometry (TIMS). The Sm-Nd-Sr-Pb data simply reflect the scale of the perturbation of upper part (0-15 cm) of the sequences, which is much more pronounced in east flank than crossing and west bordering ridge areas. The Pb-Pb systematics show that the intensity of water mass mixing modulates degree of contamination and induced the modal transport of detrital major transport processes of pollutant downwards to the sediments are proposed: (i) sediments entrainment in the eastern flank and over ridge axis primarily dominated by vertical flux of particulates controlled by repackage and dislocation by strong mechanical mixing; and (ii) in the west flank, advection of abyssal waters, due to well-stratified mixing layer, provides particulates from the NEADW1 and DSOW.

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Section: Methodsmentioning

confidence: 99%

Section: Differential Dilution Of Terrigenous Inputs By Biogenic Carbonates Vs Mixing Process Between Mantle and Crustal Materialsmentioning

confidence: 99%

Section: Differential Dilution Of Terrigenous Inputs By Biogenic Carbonates Vs Mixing Process Between Mantle and Crustal Materialsmentioning

confidence: 99%

Section: Main Driving Mechanism Of the Mantle Componentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impacts of Deep Water Structuring on Seabed Pollution Levels: Evidence from Radiogenic Isotopes (Pb-Sr-Nd) in Surface Sediments Along the Reykjanes Ridge (Southern Iceland)

Karimou

Konaté

Ali

et al. 2019

ESJ

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Impact of melting of the Laurentide Ice Sheet on sediments from the upper continental slope off southeastern Canada: evidence from Sm–Nd isotopesThis article is one of a series of papers published in this Special Issue on the themePolar Climate Stability Network.

2008

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We present new Sm–Nd isotope data for sediments from a core located on the continental slope of the St. Pierre Bank of Canada’s east coast. The Nd analyses indicate that the sediments were derived from two principal sources: the North American Shield that yields an average early Proterozoic isotopic signature and a younger Proterozoic signature attributed to Appalachian crustal sources. The Appalachian-sourced sediments predominated during the last glacial maximum (LGM) and were associated with low sedimentation rates (<30 cm/ka), with the exception of a strong North American Shield signature present in a detrital carbonate layer that corresponds to Heinrich Layer 1 (H1). The dominance of the Appalachian signature decreased subsequent to H1. The Appalachian signatures closely follow the distribution of sediments interpreted as locally derived glacial tills, while the North American Shield signatures follow the distribution of hemipelagic mud that was likely deposited by the Labrador Current. The Nd data are consistent with the persistence of the Wisconsinan Ice Sheet coverage of Newfoundland and the Grand Banks after the LGM, although the coverage began to wane prior to 12.5 ka as evidenced by the increasing influence of the Labrador Current. However, an increase in the Appalachian isotope signature at the close of the Younger Dryas event likely indicates the final melting of the ice sheet covering the Grand Banks and the Avalon Peninsula, and the initiation of the Labrador Current’s modern circulation pathway.

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Géochimie isotopique Sr-Nd-Pb des sédiments accumulés depuis 700 000 ans le long de la dorsale de Reykjanes (58-60ʻ Nord) /

Cited by 2 publications

References 105 publications

Impacts of Deep Water Structuring on Seabed Pollution Levels: Evidence from Radiogenic Isotopes (Pb-Sr-Nd) in Surface Sediments Along the Reykjanes Ridge (Southern Iceland)

Impacts of Deep Water Structuring on Seabed Pollution Levels: Evidence from Radiogenic Isotopes (Pb-Sr-Nd) in Surface Sediments Along the Reykjanes Ridge (Southern Iceland)

Impact of melting of the Laurentide Ice Sheet on sediments from the upper continental slope off southeastern Canada: evidence from Sm–Nd isotopesThis article is one of a series of papers published in this Special Issue on the themePolar Climate Stability Network.

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