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| Format: | Artículo científico |
| Language: | en |
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Academia Brasileira de Ciências
2012
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| Online Access: | https://www.redalyc.org/articulo.oa?id=32722628020 |
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Table of Contents:
- U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration Farid Chemale Jr Koji Kawashita Ivo A. Dussin Janaína N. Ávila Dayvisson Justino Anelise Bertotti Multidisciplinaria (Ciencias Naturales y Exactas) MC MS ICP Multi SHRIMP The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 Mm and, in some cases, of 15 and 40 μm. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages. 2012 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32722628020 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.84