Zircon M257 - a homogeneous natural reference material for the ion microprobe U-Pb analysis of zircon
- Author(s)
- Lutz Nasdala, Wolfgang Hofmeister, Nicholas Norberg, James M. Mattinson, Fernando Corfu, Wolfgang Dörr, Sandra L. Kamo, Allen K. Kennedy, Andreas Kronz, Peters W. Reiners, Dirk Frei, Jan Kosler, Yusheng Wan, Hans J. Götze, Tobias Häger, Alfred Körner, John W. Valley
- Abstract
We introduce and propose zircon M257 as a future reference material for the determination of zircon U-Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS-determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for 206pb/238U and 0.7392 ± 0.0003 for 207pb/235U. Its 206pb/238U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U-Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ~ 840 µg g-1 U (Th/U ~ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit-cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the "Sri Lankan trends", with actinide concentrations, U-Pb age, and the calculated alpha fluence of 1.66 × 1018 g-1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc-silicate skarn.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- Johannes Gutenberg-Universität Mainz, Curtin University, Georg-August-Universität Göttingen, University of Wisconsin, Madison, Charles University Prague, Christian-Albrechts-Universität zu Kiel, Washington State University, Justus-Liebig-Universität Gießen (JLU), Geological Survey of Denmark and Greenland (GEUS), Chinese Academy of Geological Sciences, University of California, Santa Barbara, University of Oslo, University of Toronto
- Journal
- Geostandards and Geoanalytical Research
- Volume
- 32
- No. of pages
- 19
- ISSN
- 1639-4488
- DOI
- https://doi.org/10.1111/j.1751-908X.2008.00914.x
- Publication date
- 2008
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105113 Crystallography, 1030 Physics, Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/575b7cf1-2c42-45c7-bb87-741ac12af09a