Neodymium isotope constraints on provenance, dispersal, and climate-driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years

van der Lubbe, H. J. L., Frank, Martin, Tjallingii, Rik and Schneider, Ralph R. (2016) Neodymium isotope constraints on provenance, dispersal, and climate-driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years Geochemistry, Geophysics, Geosystems, 17 (1). pp. 181-198. DOI 10.1002/2015GC006080.

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Abstract

Marine sediments deposited off the Zambezi River that drains a considerable part of the southeast African continent provide continuous records of the continental climatic and environmental conditions.
Here we present time series of neodymium (Nd) isotope signatures of the detrital sediment fraction during the past ~45,000 years, to reconstruct climate-driven changes in the provenance of clays deposited along the Mozambique Margin. Coherent with the surface current regime, the Nd isotope distribution in surface sediments reveals mixing of the alongshore flowing Zambezi suspension load with sediments supplied by smaller rivers located further north. To reconstruct past changes in sediment provenances, Nd isotope signatures
of clays that are not significantly fractionated during weathering processes have been obtained from core 64PE304-80, which was recovered just north of the Zambezi mouth at 1329 m water depth. Distinctly unradiogenic clay signatures (ENd values <214.2) are found during the Last Glacial Maximum, Heinrich Stadial 1, and Younger Dryas. In contrast, the Nd isotope record shows higher, more radiogenic isotope signatures during Marine Isotope Stage 3 and between ~15 and ~5 ka BP, the latter coinciding with the timing of the northern hemisphere African Humid Period. The clay-sized sediment fraction with the least radiogenic Nd isotope signatures was deposited during the Holocene, when the adjacent Mozambique Shelf became completely flooded. In general, the contribution of the distinctly unradiogenic Zambezi suspension load has followed the intensity of precession-forced monsoonal precipitation and enhanced during periods of increased southern hemisphere insolation and high-latitude northern hemispheric climate
variability.

Document Type: Article
Additional Information: WOS:000370620600012
Keywords: Zambezi River; neodymium isotopes; clay provenances; Mozambique Channel; southeast African monsoon; continental margin; RV METEOR; M75/3; RV Pelagia; 64PE304
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
HZG
Refereed: Yes
DOI etc.: 10.1002/2015GC006080
ISSN: 1525-2027
Related URLs:
Projects: GATEWAYS
Expeditions/Models:
Date Deposited: 24 Feb 2016 13:40
Last Modified: 19 Dec 2017 12:45
URI: http://eprints.uni-kiel.de/id/eprint/31522

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