The University of Southampton
University of Southampton Institutional Repository

Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering

Bayon, G., Burton, K.W., Soulet, G., Vigier, N., Dennielou, B., Etoubleau, J., Ponzevera, E., German, C.R. and Nesbitt, R.W. (2009) Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering Earth and Planetary Science Letters, 277, (3-4), pp. 318-326. (doi:10.1016/j.epsl.2008.10.028).

Record type: Article


The combined use of Lu–Hf and Sm–Nd isotope systems potentially offers a unique perspective for investigating continental erosion, but little is known about whether, and to what extent, the Hf–Nd isotope composition of sediments is related to silicate weathering intensity. In this study, Hf and Nd elemental and isotope data are reported for marine muds, leached Fe-oxide fractions and zircon-rich turbidite sands collected off the Congo River mouth, and from other parts of the SE Atlantic Ocean. All studied samples from the Congo fan (muds, Fe-hydroxides, sands) exhibit indistinguishable Nd isotopic composition (?Nd ~ ? 16), indicating that Fe-hydroxides leached from these sediments correspond to continental oxides precipitated within the Congo basin. In marked contrast, Hf isotope compositions for the same samples exhibit significant variations. Leached Fe-hydroxide fractions are characterized by ?Hf values (from ? 1.1 to + 1.3) far more radiogenic than associated sediments (from ? 7.1 to ? 12.0) and turbidite sands (from ? 27.2 to ? 31.6). ?Hf values for Congo fan sediments correlate very well with Al/K (i.e. a well-known index for the intensity of chemical weathering in Central Africa). Taken together, these results indicate that (1) silicate weathering on continents leads to erosion products having very distinctive Hf isotope signatures, and (2) a direct relationship exists between ?Hf of secondary clay minerals and chemical weathering intensity.
These results combined with data from the literature have global implications for understanding the Hf–Nd isotope variability in marine precipitates and sediments. Leached Fe-hydroxides from Congo fan sediments plot remarkably well on an extension of the ‘seawater array’ (i.e. the correlation defined by deep-sea Fe–Mn precipitates), providing additional support to the suggestion that the ocean Hf budget is dominated by continental inputs. Fine-grained sediments define a diffuse trend, between that for igneous rocks and the ‘seawater array’, which we refer to as the ‘zircon-free sediment array’ (?Hf = 0.91 ?Nd + 3.10). Finally, we show that the Hf–Nd arrays for seawater, unweathered igneous rocks, zircon-free and zircon-bearing sediments (?Hf = 1.80 ?Nd + 2.35) can all be reconciled, using Monte Carlo simulations, with a simple weathering model of the continental crust.

Full text not available from this repository.

More information

Published date: 30 January 2009
Keywords: neodymium isotopes, hafnium isotopes, silicate weathering, continental erosion, seawater array, Congo fan


Local EPrints ID: 71960
ISSN: 0012-821X
PURE UUID: 788159f2-0dc5-4b43-9df3-257009199f1a

Catalogue record

Date deposited: 12 Jan 2010
Last modified: 18 Jul 2017 23:57

Export record



Author: G. Bayon
Author: K.W. Burton
Author: G. Soulet
Author: N. Vigier
Author: B. Dennielou
Author: J. Etoubleau
Author: E. Ponzevera
Author: C.R. German
Author: R.W. Nesbitt

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton:

ePrints Soton supports OAI 2.0 with a base URL of

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.