The rhenium isotope composition of Atlantic Ocean seawater

The concentrations and isotopic compositions of rhenium are presented from seawater samples obtained from the primary station for the Bermuda Atlantic Time Series Study in the North Atlantic Ocean and from the 40oS UK GEOTRACES expedition in the South Atlantic Ocean. Salinity-normalized Re concentra...

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Bibliographic Details
Published in:Geochimica et Cosmochimica Acta
Main Authors: Dickson, AJ, Hsieh, Y-T, Bryan, A
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2020
Subjects:
Online Access:https://doi.org/10.1016/j.gca.2020.02.020
https://ora.ox.ac.uk/objects/uuid:da64fbef-cd98-428e-a382-c994c1441bdb
Description
Summary:The concentrations and isotopic compositions of rhenium are presented from seawater samples obtained from the primary station for the Bermuda Atlantic Time Series Study in the North Atlantic Ocean and from the 40oS UK GEOTRACES expedition in the South Atlantic Ocean. Salinity-normalized Re concentrations in both locations range between ∼6.8–7.7 ppt between 50–5000 m depth, consistent with previously published concentration data from the North Atlantic and North Pacific Oceans. Rhenium isotope values (expressed as δ187/185Re relative to NIST 3143) exhibit minimal variation around an average value of −0.17 ± 0.12‰ (n = 12, 2 S.D.), irrespective of water depth or water mass. These results confirm that the isotopic composition of perrhenate (ReO4−) in seawater is uniform. The new data establish a baseline for evaluating the isotopic mass balance of Re, and for future assessments of whether this global cycle can be disturbed by changes in seafloor redox and/or global weathering rates.