Interlaboratory reproducibility of ID-TIMS U-Pb geochronology evaluated with a pre-spiked natural zircon solution
Name
gchron-7-409-2025.pdf
Size
3.01 MB
Format
Adobe PDF
Checksum (MD5)
3da1563bbc6415d8c16fa17029f72a97
Author(s)
Szymanowski, Dawid
Wotzlaw, Jörn-Frederik
Ovtcharova, Maria
Schoene, Blair
Schaltegger, Urs
Schmitz, Mark
Ickert, Ryan
Chelle-Michou, Cyril
Chamberlain, Kevin
Crowley, James
Date Issued
September 4, 2025
Journal
Geochronology
Publisher
Copernicus GmbH
Citation
Szymanowski, D., Wotzlaw, J.-F., Ovtcharova, M., Schoene, B., Schaltegger, U., Schmitz, M. D., Ickert, R. B., Chelle-Michou, C., Chamberlain, K. R., Crowley, J. L., Davies, J. H. F. L., Eddy, M. P., Gaynor, S. P., Käßner, A., Mohr, M. T., Paul, A. N., Ramezani, J., Tapster, S., Tichomirowa, M., von Quadt, A., and Wall, C. J.: Interlaboratory reproducibility of ID-TIMS U–Pb geochronology evaluated with a pre-spiked natural zircon solution, Geochronology, 7, 409–425.
Version
Final published version
Abstract
The highest precision and accuracy in U–Pb geochronology is achieved using isotope dilution thermal ionisation mass spectrometry (ID-TIMS), a technique which owes its reliability to precise Pb and U isotope ratio analysis, a largely unified framework of lab protocols, and common isotopic tracers with accurately determined compositions. However, while hardware and protocol developments have steadily improved the analytical precision, the level to which ID-TIMS U–Pb dates from different laboratories agree remains largely unquantified. To better assess both internal repeatability and interlaboratory reproducibility of this method, we have conducted an experiment in which a large batch of natural zircon was dissolved, mixed with a newly prepared 205Pb–233U–235U tracer, and distributed as solution to participating laboratories. Thus prepared, pre-spiked, homogeneous PLES535 solution underwent the full sample preparation and analysis process separately in each lab, allowing a maximally unbiased comparison of the entire analytical procedure on a sample of unknown age. The results from 14 instruments at 11 institutions demonstrate internal repeatability of individual labs at 5 to 10 U–Pb analyses, with mean squared weighted deviation (MSWD) values generally indicative of single age populations. Lab weighted mean 206Pb / 238U and 207Pb / 235U ages for the 337 Ma zircon solution agree within 0.05 % and 0.09 % (2 standard deviations), respectively. This underscores the reliability of the participating laboratories for precise and accurate zircon U– Pb analyses, while highlighting the need for continued exchange on lab protocols and method improvement. We identify likely reasons for the remaining interlaboratory bias and discuss ways forward toward the goal of 0.01 % reproducibility.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/gchron-7-409-2025
