High-precision mass-dependent molybdenum isotope variations in magmatic rocks determined by double-spike MC-ICP-MS

Matthias Willbold*, Kate Hibbert, Yi-Jen Lai, Heye Freymuth, Remco C. Hin, Christopher Coath, Flurin Vils, Tim Elliott

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)
15 Downloads (Pure)

Abstract

Small mass-dependent variations of molybdenum isotope ratios in oceanic and island arc rocks are expected as a result of recycling altered oceanic crust and sediments into the mantle at convergent plate margins over geological timescales. However, the determination of molybdenum isotope data precise and accurate enough to identify these subtle isotopic differences remains challenging. Large sample sizes - in excess of 200 mg - need to be chemically processed to isolate enough molybdenum in order to allow sufficiently high-precision isotope analyses using double-spike MC-ICP-MS techniques. Established methods are either unable to process such large amounts of silicate material or require several distinct chemical processing steps, making the analyses very time-consuming. Here, we present a new and efficient single-pass chromatographic exchange technique for the chemical isolation of molybdenum from silicate and metal matrices. To test our new method, we analysed USGS reference materials BHVO-2 and BIR-1. Our new data are consistent with those derived from more involved and time-consuming methods for these two reference materials previously published. We also provide the first molybdenum isotope data for USGS reference materials AGV-2, the GSJ reference material JB-2 as well as metal NIST SRM 361.

Original languageEnglish
Pages (from-to)389-403
Number of pages15
JournalGeostandards and Geoanalytical Research
Volume40
Issue number3
DOIs
Publication statusPublished - Sep 2016
Externally publishedYes

Bibliographical note

Copyright the Author(s) 2015. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • molybdenum
  • Mo
  • mass-dependent
  • stable isotopes
  • oceanic basalts
  • mantle recycling
  • anionic chromatographic exchange
  • double spike
  • MC-ICP-MS

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