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| Bühn,Bernhard; Pimentel,Márcio M.; Matteini,Massimo; Dantas,Elton L.. |
| Age determinations using the 235U and 238U radioactive decay series to the daughter isotopes 207Pb and 206Pb, respectively, using the mineral zircon (ZrSiO4), are widely used to decipher geological processes. A new method developed in the last couple of years, the laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), overcomes previous laborious sample preparation, and yields isotopic ratios and age data with a high spatial resolution of ten of microns. The present study describes the analytical set-up and data reduction process as presently applied at the Laboratory for Geochronology of the University of Brasília. It explores the precision and accuracy of the method by cross-analysing three international zircon... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geochronology; U-Pb isotopes; LA-MC-ICP-MS; Zircon; Age dating. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652009000100011 |
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| HARTMANN,LÉO A.; SANTOS,JOÃO O. S.; McNAUGHTON,NEAL J.; VASCONCELLOS,MARCOS A. Z.; DASILVA,LUIZ C.. |
| Complex polymetamorphic granulites have been dated in the Santa Catarina granulite complex of southern Brazil through SHRIMP study of zircon. This complex is dominated by intermediate-acid plutonic rocks and contains small volumes of mafic and ultramafic rocks, and minor quartzite and banded iron formation. Porphyroblasts of orthopyroxene, clinopyroxene and plagioclase in mafic and acid rocks are interpreted as magmatic remnants in a volumetrically dominant granoblastic aggregate (M1) of the same minerals and hornblende. Hornblende formed during a later M2 metamorphic event constitutes rims around pyroxene, but the hornblende is also rimmed by granoblastic simplectites of orthopyroxene, clinopyroxene, hornblende and plagioclase in a second granulite facies... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Granulites; SHRIMP; U/Pb geochronology; Santa Catarina granulite complex; Brazil; Symplectites; Zircon. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652000000400007 |
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