Revista de la Asociación Geológica Argentina
versión On-line ISSN 1851-8249
VARELA, Ricardo; BASEI, Miguel A.S. y PEREYRA, Claudia P.. U-Pb dating of the Paimán Granite, Sierra de Paimán, Chilecito, La Rioja. Rev. Asoc. Geol. Argent. [online]. 2008, vol.63, n.1, pp. 97-101. ISSN 1851-8249.
Conventional U-Pb zircon ages for the Paimán Granite are presented. The magmatic unit crops out in the eastern border of the Famatina range. Five zircon fractions were analysed from a coarse porphyritic granitoid, the major component in the Paimán-Chilecito area. Results are concordant for the five fractions and the mean 206 Pb/ 238 U age of 477.6 ± 4.1 Ma is Early Ordovician. This age confirms that the Paimán Granite is part of the Ocloyic magmatic phase and Famatinian belt. The present age together with the previous U-Pb ages from granitoids of the Famatinian belt between 28º and 33º S suggest that the magmatic activity occurred over a short time span of about 20 Ma, following no noticeable internal polarity within the belt.
Palabras clave : Paimán Granite; Chilecito; U-Pb age; Early Ordovician; Famatinian belt.