Decoupling of dissolved and bedrock neodymium isotopes during sedimentary cycling

Hindshaw, R. S. and Aciego, S. M. and Piotrowski, A. M. and Tipper, E. T. (2018) Decoupling of dissolved and bedrock neodymium isotopes during sedimentary cycling. Geochemical Perspectives Letters, 8. pp. 43-46. ISSN 2410-3403 DOI https://doi.org/10.7185/geochemlet.1828

Text (PDF includes supplemental information) GPL1828_SI.pdf - Published Version Available under License Creative Commons Attribution. Download (2MB)

Abstract

The radiogenic neodymium isotope ratio143Nd/144Nd (expressed as εNd) has been applied to examine seawater elemental budgets, sedimentary provenance, oceanic water mass source and circulation, large scale geochemical cycling, and continental crust growth rates. These applications are underpinned by the assumption that during sedimentary processing the parent/daughter (samarium/neodymium) ratio is conservative during low temperature fluid related processes. In this study, we report εNd data from two streams draining sedimentary formations in the Arctic archipelago of Svalbard. The εNd value of the dissolved load is offset from stream suspended sediment samples by up to 5.5 epsilon units. We demonstrate that dissolved load εNd values are controlled by the dissolution of labile phases present in the catchment rocks which are isotopically distinct from the silicate residue and account for up to 12 % Nd in the bulk sediment. This study highlights; 1) the potential for incongruent release of Nd isotopes to seawater from rocks and sediments, with implications for the isotopic composition of seawater, and 2) the large scale decoupling between a rapidly exchanging labile reservoir and a silicate-bound reservoir during sediment recycling.

Item Type:	Article
Uncontrolled Keywords:	2018AREP; IA76
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions:	01 - Climate Change and Earth-Ocean Atmosphere Systems 07 - Gold Open Access
Journal or Publication Title:	Geochemical Perspectives Letters
Volume:	8
Page Range:	pp. 43-46
Identification Number:	https://doi.org/10.7185/geochemlet.1828
Depositing User:	Sarah Humbert
Date Deposited:	16 May 2020 01:40
Last Modified:	16 May 2020 01:40
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4746

Actions (login required)

View Item