View article

Quantifying time in geosciences often utilises the U-Pb technique, commonly applied to single crystals or sub-crystal domains of U-bearing minerals. Among the available analytical approaches, 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 isotope ratio analysis, a largely unified framework of lab protocols and common standard materials with accurately determined compositions. However, while hardware developments steadily improve the analytical precision, the level at which different ID-TIMS laboratories agree remains largely unquantified. As results from multiple labs are compared at sub-permil levels of precision, it becomes ever more important that inter-lab reproducibility is known and accounted for.