The experimental procedure for Sm-Nd method performed at the Pará-Iso Isotope Geology laboratory, (Federal University of Pará) is described in details as a reference for the customers of the Pará-Iso. Sm-Nd dating of felsic granulites from the Tartarugal Grande area, northeastern of the Archean Amapá Block, (Southeastern Guyana Shield) furnished whole rock - garnet isochron ages of 2017 ± 12 Ma, 1981.6 ± 2.8 Ma e 2018 ± 2.3 Ma. Dating of the same samples at the UnB geochronological laboratory yielded ages of 2037 ± 8.4 Ma, 1988 ± 11 Ma e 2013 ± 15 Ma, respectively. Such results indicate that temperature of at least 700°C was reached by the Tartarugal Grande granulites between 2.04 - 1.98 Ga, as a proxy of a late Transamazonian high grade metamorphic event in the northeastern sector of the Archean Amapá Block. TDM(Nd) model ages between 3.15 Ga and 2.79 Ga are a further evidence of a major Mesoarchean crustal growth episode in the southeastern Guyana Shield.
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