Resumo

APARICIO GONZALEZ, Pamela A; PIMENTEL, Marcio M  e  HAUSER, Natalia. LA-ICP-MS U-Pb age from granitic dikes fr om the Pampean cycle, Sierra de Mo/otoro, Cordillera Oriental. Rev. Asoc. Geol. Argent. [online]. 2011, vol.68, n.1, pp.33-38. ISSN 0004-4822.

A zircon U-Pb age obtained with the LA-ICP-MS method is presented for a granite porphyry from Chachapoyas Formation (nom. nop.), sierra de Mojotoro, NW Argentina. 20 euhedral zircons with acicular prismatic and transparent morphology were analyzed. The data obtained is concordant in eight zircons grains and show a crystallization age of 533 ± 2 Ma. The new data could be associated with igneous rocks of similar ages located in the Eastern Cordillera, and suggest an acid magmatic event during the Lower Cambrian. This outcrop represents the southern expression of the Pampean magmatic arc in the NW of Argentina.

Palavras-chave : Basement; Granite porphyry; Lower-Middle Cambrian; Mojotoro; Eastern Cordillera.

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