Cambrian and Ordovician magmatism in Northern Patagonia: a record of the Pampean and Famatinian orogens?

LÓPEZ DE LUCHI, M. G.; RAPALINI, A.E.; TOHVER, E.; MARTÍNEZ DOPICO, C.; WEMMER, K.; CAWOOD, P.

Medellín

Simposio; 8th South American Symposium on Isotope Geology Medellin; 2012

CORPOGEMMAS y otras

We present new SHRIMP zircon dating on the low grade metaclastic Nahuel Niyeu Fm (NNF) and the metaigneous Tardugno Granodiorite (TG) both located west of Valcheta town in the NE sector of the North Patagonian Massif. The pervasive deformed TG (see López de Luchi et al, 2010, and references therein), was considered as Precambrian (Chernicoff and Caminos, 1996) or late Carboniferous (Basei et al. 2002). Magmatic zircons of the sample SA114 from the type locality yielded a very well defined mean age of 528.5±3.5 Ma. New detrital ages on NNF which is in tectonic contact with TG indicate that the protoliths are older than 515 Ma, in agreement with previous data (Pankhurst et al, 2006).