| Institution: | 1. John de Laeter Centre, Curtin University, Kent. St., Bentley, 6102, Western Australia;2. Department of Earth Sciences, University of Geneva, Rue des Maraichers 13, CH-1205 Geneva, Switzerland
Department of Earth Sciences, Università degli Studi di Milano, Via Mangiagalli 32, 20133, Milan, Italy;3. Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID, 83725-1535 USA;4. Department of Earth Sciences, University of Geneva, Rue des Maraichers 13, CH-1205 Geneva, Switzerland;5. Adelaide Microscopy, The University of Adelaide, SA, 5005 Adelaide, Australia;6. Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009 Australia;7. School of Geosciences, University of Edinburgh, The King's Building, James Hutton Road, EH9 3FE Edinburgh, UK;8. Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, H3A 0E8 Canada |
| Abstract: | Twelve apatite samples have been tested as secondary ion mass spectrometry (SIMS) reference materials. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis shows that the SLAP, NUAN and GR40 apatite gems are internally homogeneous, with most trace element mass fractions having 2 standard deviations (2s) ≤ 2.0%. BR2, BR5, OL2, AFG2 and AFB1, which have U > 63 μg g-1, 206Pb/204Pb > 283, and homogeneous SIMS U-Pb data, have respective isotope dilution thermal ionisation mass spectrometry (ID-TIMS) ages of 2053.83 ± 0.21 Ma, 2040.34 ± 0.09 Ma, 868.87 ± 0.25 Ma, 478.71 ± 0.22 Ma and 473.25 ± 0.09 Ma. Minor U-Pb heterogeneity exists and accurate SIMS results require correction with the 3D Concordia-constrained common Pb composition. Among the studied samples, AFG2 and BR5 are the most homogeneous U-Pb reference materials. The SIMS sulfur isotopic compositions of eight of the apatites shows they are homogeneous, with 2s for both 103δ34S and 103δ33S < 0.55‰. One apatite, BR96, has Δ33S = -0.36 ± 0.2‰. The apatite samples have ID-TIMS 87Sr/86Sr between 0.704214 ± 0.000030 and 0.723134 ± 0.000035. |
