High‐Precision Fe and Mg Isotope Ratios of Silicate Reference Glasses Determined In Situ by Femtosecond LA‐MC‐ICP‐MS and by Solution Nebulisation MC‐ICP‐MS. Issue 3 (7th August 2014)

• Record Type: Journal Article
• Authors: Oeser, Martin; Weyer, Stefan; Horn, Ingo; Schuth, Stephan
• Is Part Of: Geostandards and geoanalytical research. Volume 38:Issue 3(2014)
• Page Start: 311
• Page End: 328
• Publication Date: 2014-08-07
• Subjects: Analytical geochemistry -- Periodicals; Géochimie analytique -- Périodiques; 551.9
• DOI: 10.1111/j.1751-908X.2014.00288.x
• Languages: English
• ISSNs: 1639-4488

Abstract

<abstract abstract-type="main" id="ggr0288-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>In this study, a technique for high precision <italic>in situ</italic> Fe and Mg isotope determinations by femtosecond‐laser ablation‐multi collector‐ICP‐MS (fs‐LA‐MC‐ICP‐MS) was developed. This technique was employed to determine reference values for a series of common reference glasses that may be used for external standardisation of <italic>in situ</italic> Fe and Mg isotope determinations in silicates. The analysed glasses are part of the MPI‐DING and United States Geological Survey (USGS) reference glass series, consisting of basaltic (BIR‐1G, BCR‐2G, BHVO‐2G, KL2‐G, ML3B‐G) and komatiitic (GOR128‐G and GOR132‐G) compositions. Their Fe and Mg isotope compositions were determined by <italic>in situ</italic> fs‐LA‐MC‐ICP‐MS and by conventional solution nebulisation multi‐collector ICP‐MS. We determined δ<sup>56</sup>Fe values for these glasses ranging between ‐0.04‰ and 0.10‰ (relative to IRMM‐014) and δ<sup>26</sup>Mg values ranging between ‐0.40‰ and ‐0.15‰ (relative to DSM‐3). Our fs‐LA‐MC‐ICP‐MS results for both Fe and Mg isotope compositions agreed with solution nebulisation analyses within analytical uncertainties. Furthermore, the results of three USGS reference glasses (BIR‐1G, BHVO‐2G and BCR‐2G) agreed with previous results for powdered and dissolved aliquots of the same reference materials. Measurement reproducibilities of the <italic>in situ</italic> determinations of δ<sup>56</sup>Fe and δ<sup>26</sup>Mg values were usually better than 0.12‰ and 0.13‰ (2<italic>s</italic>), respectively. We further demonstrate that our technique is a suitable tool to resolve isotopic zoning in chemically‐zoned olivine crystals. It may be used for a variety of different applications on isotopically‐zoned minerals, e.g., in magmatic or metamorphic rocks or meteorites, to unravel their formation or cooling rates.</p> </abstract>