Chemical Geology
Chemical Geology
4 years ago

Improved accuracy of LA-ICP-MS U-Pb ages of Cenozoic zircons by alpha dose correction

Improved accuracy of LA-ICP-MS U-Pb ages of Cenozoic zircons by alpha dose correction
While Laser Ablation Inductively-Coupled-Plasma Mass Spectrometry (LA-ICP-MS) is the method of choice for U-Pb dating of zircons in provenance analysis, its application to young (<100Ma) zircons is hindered by systematic analytical bias. In magmatic petrology, where the majority of studied units are young, this often places zircon dates at odds with established 40Ar/39Ar eruption ages or high-precision ID-TIMS crystallization ages. Zircon lattice properties, particularly the degree of lattice damage caused by the radioactive decay of U and Th, impart analytical bias by causing differential ablation rates and therefore differential fractionation of U and Pb throughout each analysis. Although it is possible to normalize the zircon lattice strengths to calibration reference zircons by thermal annealing to some extent, this may not entirely alleviate the problem. In this study, the effects of alpha decay dose (i.e., degree of radiation damage) on analytical biases in age determination are examined by analyzing a number of zircon reference materials under well-constrained analytical parameters. A regression-based, multi-standard correction method is demonstrated, which improves the accuracy of age data, particularly in young (Cenozoic) zircons. A novel data reduction scheme (Dose_Corrector.ipf) is introduced, which runs in conjunction with the widely-used Igor Pro/Iolite platform and performs a correction for alpha dose and Th disequilibrium. This scheme improves the accuracy of age data for unannealed zircons, and its utility is demonstrated by applying it to zircons from several well-studied units.

Publisher URL: www.sciencedirect.com/science

DOI: S0009254117305168

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.