Chemical abrasion applied to LA-ICP-MS U–Pb zircon geochronology

Quentin G. Crowley, Kyle Heron, Nancy R Riggs, Balz Kamber, David Chew, Brian McConnell, Keith Benn

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Zircon (ZrSiO<inf>4</inf>) is the most commonly used mineral in U–Pb geochronology. Although it has proven to be a robust chronometer, it can suffer from Pb-loss or elevated common Pb, both of which impede precision and accuracy of age determinations. Chemical abrasion of zircon involves thermal annealing followed by relatively low temperature partial dissolution in HF acid. It was specifically developed to minimize or eliminate the effects of Pb-loss prior to analysis using Thermal Ionization Mass Spectrometry (TIMS). Here we test the application of chemical abrasion to Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) by analyzing zircons from both untreated and chemically abraded samples. Rates of ablation for high alpha-dose non-treated zircons are up to 25% faster than chemically abraded equivalents. Ablation of 91500 zircon reference material demonstrates a ca. 3% greater down-hole fractionation of<sup>206</sup>Pb/<sup>238</sup>U for non-treated zircons. These disparities necessitate using chemical abrasion for both primary reference material and unknowns to avoid applying an incorrect laser induced fractionation correction. All treated samples display a marked increase in the degree of concordance and/or lowering of common Pb, thereby illustrating the effectiveness of chemical abrasion to LA-ICP-MS U–Pb zircon geochronology.

Original languageEnglish (US)
Pages (from-to)503-518
Number of pages16
JournalMinerals
Volume4
Issue number2
DOIs
StatePublished - Jun 3 2014

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Keywords

  • Chemical abrasion
  • Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)
  • Pb-loss
  • U–Pb geochronology
  • Zircon

ASJC Scopus subject areas

  • Geology
  • Geotechnical Engineering and Engineering Geology

Cite this

Crowley, Q. G., Heron, K., Riggs, N. R., Kamber, B., Chew, D., McConnell, B., & Benn, K. (2014). Chemical abrasion applied to LA-ICP-MS U–Pb zircon geochronology. Minerals, 4(2), 503-518. https://doi.org/10.3390/min4020503