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Apatite, an important mineral widely distributed in various geological environments, can be used for in situ U–Pb dating and Sr–Nd isotope analyses. The LA-ICPMS U–Pb dating and Sr–Nd isotopic determinations require suitable matrix-matched reference materials. Current apatite standards are rare and have some defects. Most natural apatite references display high and variable common Pb, which may be the most difficult issue in microbeam determination. We provided a gem-quality apatite MAP-3, subjected to detailed major- and trace element composition, U–Pb dating, and Sr–Nd isotopic analyses to assess its homogeneity of chemical composition and suitability as a reference material for microbeam U–Pb dating and Nd isotope analyses. Through comprehensive analyses, we show that the MAP-3 apatite is free of mineral inclusions and is uniform at the level of analytical precision of major- and trace element, U–Pb isotopic, and Nd isotopic ratios despite compositional zones from CL images. The MAP-3 apatite has ID-TIMS determined mean isotopic ratio values of 0.13222 ± 0.00016 for 206Pb/238U, 1.2084 ± 0.0030 for 207Pb/235U, and 0.0663 ± 0.0001 for 207Pb/206Pb and the weighted mean 206Pb/238U ages of 800.5 ± 0.9 Ma (2 s, MSWD = 1.5, n = 11). The 143Nd/144Nd isotopic results determined by (ID)-TIMS are 0.511248 ± 0.000006 (2 s, MSWD = 4.2, n = 11) with moderate Nd contents of ∼1532 ppm. U–Pb age and Nd isotopic compositions obtained by LA-(Q, SF-SC, MC)-ICPMS analysis are reproducible and agree with the values of TIMS, which indicates that MAP-3 apatite has the potential to be a primary reference material for microbeam determination of U–Pb ages and Nd isotope analyses. To validate the effectiveness of the potential, we dated some apatite reference materials of known age and two geological apatites. The results demonstrated the high-quality U–Pb dating reference materials used with MAP-3 apatite. [ABSTRACT FROM AUTHOR]

Apatite is an essential mineral for geochronology and geochemistry. Precise and accurate U–Pb Laser ablation (LA)-inductively coupled plasma mass spectrometry (ICPMS) dating of apatite requires suitable matrix-matched reference materials (RMs), but young RMs (<30Ma) are lacking from existing apatite RMs. We provided a gem-quality apatite MAP-2 collected from Myanmar and subjected it to detailed chemical composition and U–Pb dating analyses to assess its homogeneity and suitability as a reference material for LA-ICPMS age determination. The results of comprehensive analyses of multiple methods show that the MAP-2 apatite is largely free of inclusions and is relatively homogenous in chemical and isotopic content. Notably, MAP-2 apatite could be the youngest apatite U–Pb dating reference material (about 22 Ma) with relatively high U contents range from 161 μg g−1 to 231 μg g−1 and an average of 210 μg g−1. The isotope dilution-thermal ionization mass spectrometry (ID-TIMS) U–Pb measurements yielded weighted mean isotopic ratio values of 0.00345 ± 0.00003 for 206Pb/238U, 0.0243 ± 0.0039 for 207Pb/235U, 0.0512 ± 0.0082 for 207Pb/206Pb and the weighted mean 206Pb/238U ages of 22.18 ± 0.22 Ma (2SD, MSWD = 0.01, n = 6) as the recommended reference value. LA-ICPMS analyses yielded 207Pb-corrected weighted mean 206Pb/238U age of 22.0 ± 0.1/0.2 Ma (2SD, MSWD = 4.2, n = 232) and the results are consistent with ID-TIMS data within the limits of the ID-TIMS analytical uncertainly, which indicates that MAP-2 apatite has the potential as a reference material for microbeam determination of U–Pb ages. [Display omitted] • Complete geochemical data for uniformity verification. • The youngest age apatite references materials for LA-ICPMS dating. • A gem-quality apatite available to the LA-ICPMS analytical community. [ABSTRACT FROM AUTHOR]