Rhenium elemental and isotopic variations at magmatic temperatures

• Published in: Geochemical Perspectives Letters
• Main Authors: Wang, W., Dickson, A.J., Stow, M.A., Dellinger, M., Burton, K.W., Savage, P.S., Hilton, R.G., Prytulak, J.
• Other Authors: Royal Holloway University of London (RHUL), Department of Earth Sciences Oxford, University of Oxford, Department of Earth Sciences Durham, Durham University, Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), School of Earth and Environmental Sciences University St Andrews, University of St Andrews Scotland, Natural Environment Research Council UK.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Hekla; Iceland
• Online Access: https://hal.science/hal-04420775; https://doi.org/10.7185/geochemlet.2402

International audience Recent analytical advances in the measurement of rhenium (Re) isotope ratios allow its potential as a palaeoredox and chemical weathering proxy to be explored. However, a successful isotopic proxy must be grounded by an understanding of its composition and behaviour in the solid Earth. Here, we present Re concentrations and Re isotopic (δ187Re) compositions for a well-characterised sequence of lavas from Hekla volcano, Iceland. The concentration of Re varies from 0.02 to 1.4 ng/g, decreasing from basalt to more evolved lavas. We show that the crystallisation and removal of magnetite is responsible for the Re decrease in this system. By contrast, δ187Re values for the same suite of samples show a relatively narrow range (−0.45 to −0.22 ‰), suggesting minimal resolvable Re isotope fractionation between magnetite and the silicate melt. Together with other samples, including mid-ocean ridge basalts, these first igneous data can be used to estimate a baseline for terrestrial materials (δ187Re = −0.33 ± 0.15 ‰, 2 s.d., n = 14), from which low-temperature Re isotope variations in Earth’s surficial environments can be assessed, alongside the global isotope mass balance of Re.