The University of Southampton
University of Southampton Institutional Repository

Molybdenum isotope behaviour accompanying weathering and riverine transport in a basaltic terrain

Pearce, Christopher R., Burton, Kevin W., Pogge von Strandmann, Philip A.E., James, Rachael H. and Gíslason, Sigurður R. (2010) Molybdenum isotope behaviour accompanying weathering and riverine transport in a basaltic terrain Earth and Planetary Science Letters, 295, (1-2), pp. 104-114. (doi:10.1016/j.epsl.2010.03.032).

Record type: Article


The application of the molybdenum (Mo) isotope system as a proxy for determining changes in the redox state of the oceans is predicated on the assumption that the composition of continental input can be characterised from crustal rock types, and remains constant. However, it has recently been shown that the ?98/95Mo composition of global rivers varies between 0.15‰ and 2.4‰ and is therefore systematically heavier than the average composition of the continental crust (not, vert, similar 0‰). In order to understand the processes that control Mo-isotope fractionation during weathering this study presents ?98/95Mo and Mo abundance data for rivers (and estuarine samples) from Iceland that drain predominantly basaltic terrains. Resolvable differences are observed in the isotopic composition of the riverine Mo sources; ice (?98/95Moice > 1.8‰), basaltic bedrock (?98/95Mobedrock not, vert, similar 0.0‰) and hydrothermal waters (?98/95Mohydrothermal not, vert, similar?3.4‰). Systematic changes in the dissolved Mo-isotope composition are also observed within river catchments, with ?98/95Mo values increasing from not, vert, similar 0‰ in glacial rivers (close to the source) to not, vert, similar 1‰ downstream, consistent with Mo-isotopes being fractionated during weathering. Analysis of other riverine phases (bedload, colloids and iron-precipitates) demonstrates that these phases preferentially incorporate light Mo-isotopes, and remain coupled to the dissolved load during riverine transportation. A ?98/95Mo profile through the Borgarfjörður estuary exhibits a predominantly conservative mixing behaviour, but suggests that the release of isotopically light Mo from the particulate and/or colloidal phases may occur in the low salinity part of the estuarine mixing zone.

PDF Pearce_et_al_(2010).pdf - Version of Record
Download (1MB)

More information

Published date: 15 June 2010
Keywords: molybdenum (Mo) isotopes, basaltic weathering, riverine inputs, estuarine mixing
Organisations: Marine Geoscience, National Oceanography Centre,Southampton


Local EPrints ID: 172253
ISSN: 0012-821X
PURE UUID: 3830380b-3d5a-4768-b49d-7f456c6cf62e

Catalogue record

Date deposited: 24 Jan 2011 16:01
Last modified: 18 Jul 2017 12:14

Export record



Author: Christopher R. Pearce
Author: Kevin W. Burton
Author: Philip A.E. Pogge von Strandmann
Author: Sigurður R. Gíslason

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.