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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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| Chemale Jr,Farid; Kawashita,Koji; Dussin,Ivo A.; Ávila,Janaína N.; Justino,Dayvisson; Bertotti,Anelise. |
| 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 μm 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: MC-ICP-MS; SHRIMP; Faraday cups; Multi-ion Counting System; U-Pb in situ zircon dating. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000200005 |
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