Geología y geocronología del basamento paleozoico de los Andes Norpatagónicos en el área de San Martín de los Andes.

GONZÁLEZ, PABLO DIEGO; PEDREIRA DAVID; GIACOSA RAÚL E.; MARTÍN GONZÁLEZ FIDEL; SERRA VARELA SAMANTA; HEREDIA CARBALLO NEMESIO

Huelva

Congreso; 9° Congreso Geológico de España; 2016

Sociedad Geológica de España

The pre-Mesozoic igneous and metamorphic basement of the North Patagonian Andes was named Colohuincul Complex. This basement includes medium-high grade metamorphic rocks from San MartIn de los Andes; low grade metamorphic rocks from Cuesta de Rahue and Devonian intrusive rocks (ca. 400 Ma). These rocks were deformed by different orogenic events, a pre-Wenlock event (high grade metamorphic rocks) and another one in the Upper Carboniferous ? lower Permian (Low grade metamorphic rocks and intrusive). Previous studies of detrital zircons analysis on Cuesta de Rahue metamorphic rocks have shed a maximum sedimentation age of 364 Ma (Upper Devonian). New field work in San Martín de los Andes area have recognized the high grade metamorphic rocks as roof pendants and country rocks of the Lower Devonian intrusive rocks. These metamorphic rocks would have a pre 400 Ma age. In this work we present new detrital zircon data obtained on high grade metamorphic rocks that allow us to interpret a maximum sedimentation age of 506 Ma. This age indicates that the high grade metamorphic rocks of San Martín de los Andes are the oldest known Paleozoic basement in the North Patagonian Andes.