Resumo

CORREA, MJ. Petrology and K/Ar age of dikes related to Oncán Formation, Santiago del Estero. Rev. Asoc. Geol. Argent. [online]. 2003, vol.58, n.4, pp.664-668. ISSN 0004-4822.

At the northwest of Ambargasta range, Santiago del Estero, near El Remanso and El Simbolar villages, a swarm of longitudinal dikes with a predominant NE trend crops out. The obtained age of 483±14 Ma (K/Ar WR), allows to consider this unit representative of the end of the magmatism originated during the approximation and subsequent collision of the Pampia terrane with the Río de La Plata craton. Geochemical and petrographic data allowed to correlate these rocks with the Oncán Rhyodacitic Porphyry. The studied rocks have a granitic composition, lightly peraluminous and geochemical characteristics similar to the highly evolved granitoids from the Sierra de Ambargasta.

Palavras-chave : Oncán Formation; Sierra de Ambargasta; K/Ar age.

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