Peixe Zircon as a Quality Control Reference Material in U‐Pb Geochronology by LA ‐ ICP ‐ MS

A megacryst zircon from Brazil, referred to here as Peixe#0, was evaluated as a potential reference material for LA‐ICP‐MS U‐Pb dating. Results from multi‐method characterisation – including CA‐ID‐TIMS, SIMS and a long‐term LA‐ICP‐MS data set – enabled us to assess this crystal's suitability as a reference material for routine quality control in age determinations by LA‐ICP‐MS. Using CA‐ID‐TIMS, Peixe#0 yielded mean 206 Pb/ 238 U and 207 Pb/ 235 U ratios of 0.09257 ± 0.1% and 0.7561 ± 0.1%, respectively (precisions expressed as 2RSD), and weighted mean 206 Pb/ 238 U age of 570.85 ± 0.30 Ma (2 s , MSWD = 0.40, n = 4). With the LA‐ICP‐MS compiled database (2063 individual age determinations distributed over 167 sessions spanning eight years) acquired during routine analysis at the Isotope Geology Laboratory (LAGIS) at Unicamp, Brazil, we propose a 206 Pb/ 238 U weighted mean age of 569 ± 13 Ma (2 s ), which includes the long‐term excess variance in the total uncertainty. Oxygen isotopes presented a homogeneous distribution (δ 18 O SMOW = +5.13 ± 0.15‰ (1 s )). The trace element chemical compositions varied substantially depending on the chosen cathodoluminescence zone containing distinct features. Approximately 4 g of Peixe#0 zircon are available for distribution upon request.