Rare earth elements and neodymium isotopes in world river sediments revisited

• Published in: Geochimica et cosmochimica acta 2015-12, Vol.170, p.17-38
• Main Authors: Bayon, G., Toucanne, S., Skonieczny, C., André, L., Bermell, S., Cheron, S., Dennielou, B., Etoubleau, J., Freslon, N., Gauchery, T., Germain, Y., Jorry, S.J., Ménot, G., Monin, L., Ponzevera, E., Rouget, M.-L., Tachikawa, K., Barrat, J.A.
• Format: Article
• Language: English
• Subjects: Astrophysics; Sciences of the Universe
• ISSN: 0016-7037; 1872-9533
• DOI: 10.1016/j.gca.2015.08.001

Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world’s major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes. Our results confirmed earlier assumptions that river sediments do not generally exhibit any significant grain-size dependent Nd isotopic variability. Most sediments from rivers draining old cratonic areas, sedimentary systems and volcanic provinces displayed similar Nd isotopic signatures in both clay and silt fractions, with ΔεNd(clay–silt)