EDADES U-Pb EN CIRCONES DETRÍTICOS DEL PALEOZOICO INFERIOR/MEDIO DEL SUR DE LA CORDILLERA FRONTAL, ARGENTINA: IMPLICANCIAS TECTONO-ESTRATIGRÁFICAS EN EL MARGEN PROTO-ANDINO

URIZ. NORBERTO J.; BASEI, MIGUEL ANGELO STIPP; CINGOLANI, CARLOS A.

Montevideo

Congreso; Congreso Uruguayo de Geología; 2016

Sociedad Uruguaya de Geología

U-Pb (LA-ICP-MS) detrital zircon ages from the metasedimentary Las LagunitasFormation are here presented. This unit crops out at the southern area of Cordillera Frontal, western Argentina. Data obtained support the hypothesis that the Las Lagunitas Formation could comprise at least two units: the lower one has an Upper Ordovician biostratigraphic age and records two main detrital zircon populations, one of Mesoproterozoic age and a younger one of about 600 Ma; the uppermost unit, informally known as ?Selerpe Series? shows a differentdetrital zircon age pattern, with a main Neoproterozoic population and recording ´famatinian´ ages with a youngest peak at 423 Ma (Silurian). It is therefore possible to confirm that at the eastern flank of the southern edge of the Cordillera Frontal could be subdivided in units showing different metamorphic grades and tectonic deformation features.