Trace Element Characterisation of MAD-559 Zircon Reference Material for Ion Microprobe Analysis

We document the composition of a natural zircon gemstone sourced from Madagascar, MAD-559 - a new reference material for calibrating trace element mass fractions in zircon measured by SIMS. The composition of MAD-559 was quantified by calibration relative to the well-documented zircon reference material 91500, for which we compiled existing published data (Mg, Al, Y, rare earth elements, Hf, U, Th) and performed new measurements to characterise the mass fraction of less commonly measured elements (Li, Be, B, F, Na, P, K, Ca, Sc, Ti, Fe, Nb). Measurement results of SL13, CZ3 and MAD-1 zircons and NIST SRM glasses were performed as quality control materials to test measurement bias and repeatability. We show the intermediate precision for most trace element measurement results of MAD-559 to be between +/- 3% and +/- 5% RSD based on 139 measurements by SIMS on twenty-five individual polished zircon chips measured during a 24-h period, as well as repeat measurements performed over five separate analytical sessions. Trace element mass fractions were also measured by LA-ICP-MS in two different laboratories, and major element compositions measured by electron microprobe, to compare with results measured by SIMS. Based on laser Raman and hyperspectral cathodoluminescence spectroscopy, we show MAD-559 to have high crystal disorder due to radiation damage relative to crystalline zircon (e.g., SL13 and 91500 zircon). Although the high cumulative alpha dose of MAD-559 zircon makes it a poor reference material for geochronology, the consistency of the trace element mass fraction results measured in multiple sessions and by various measurement methods shows that it is an ideal reference material for microanalytical trace element mass fraction quantification of zircon.