Investigation of thallium fluxes from subaerial volcanism-Implications for the present and past mass balance of thallium in the oceans

Geochimica et Cosmochimica Acta
By: , and 

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Abstract

A suite of 34 volcanic gas condensates and particulates from Kilauea (Hawaii), Mt. Etna and Vulcano (Italy), Mt. Merapi (Indonesia), White Island and Mt. Nguaruhoe (New Zealand) were analysed for both Tl isotope compositions and Tl/Pb ratios. When considered together with published Tl–Pb abundance data, the measurements provide globally representative best estimates of Tl/Pb = 0.46 ± 0.25 and ε205Tl = −1.7 ± 2.0 for the emissions of subaerial volcanism to the atmosphere and oceans (ε205Tl is the deviation of the 205Tl/203Tl isotope ratio from NIST SRM 997 isotope standard in parts per 10,000). Compared to igneous rocks of the crust and mantle, volcanic gases were found to have (i) Tl/Pb ratios that are typically about an order of magnitude higher, and (ii) significantly more variable Tl isotope compositions but a mean ε205Tl value that is indistinguishable from estimates for the Earth’s mantle and continental crust. The first observation can be explained by the more volatile nature of Tl compared to Pb during the production of volcanic gases, whilst the second reflects the contrasting and approximately balanced isotope fractionation effects that are generated by partial evaporation of Tl during magma degassing and partial Tl condensation as a result of the cooling and differentiation of volcanic gases.

Publication type Article
Publication Subtype Journal Article
Title Investigation of thallium fluxes from subaerial volcanism-Implications for the present and past mass balance of thallium in the oceans
Series title Geochimica et Cosmochimica Acta
DOI 10.1016/j.gca.2009.07.014
Volume 73
Issue 20
Year Published 2009
Language English
Publisher Elsevier
Description 29 p.
First page 6340
Last page 6359
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