Quantifying Long?Term Reproducibility of Zircon Reference Materials by U?Pb LA?ICP?MS Dating

Inter-session excess variance of U/Pb and Pb/Pb ratios in LA-ICP-MS zircon dating is the largest contributor to systematic errors, which turn limit accuracy age determinations. Quantifying long-term reference materials allows for estimation samples, but such compilations are not available literature. Here, we present results over 100 measurement sessions six years seven common calculate a characteristic each. For 206Pb/238U ages, these values (2s) are: AusZ7-1 = 1.7% (115 sessions), AusZ7-5 0% (74), OD-3 0.6% (19), Temora2 1.2% (86), Plešovice 1.1% (100), 91500 1.0% (146) Mud Tank 3.0% (12). 207Pb/206Pb smaller variances observed: 0.3%, 0.4%, 0.4%. These well-constrained estimates inter-session ETH Zürich laboratory using sector-field ICP-MS, may provide either first-order estimate other laboratories, or value compare against their own material compilations.