In the Andean Frontal Cordillera two tectonostratigraphlc main groups can be defined: a gondwanic basament constituted by devonian and Permo-Carboniferous marine sedimentary rocks, intruded by Upper Paleozoic granitic rocks, and Andean continental volcanic and volcanoclastic unit, essentially Mesozoic and Tertiary, intruded by Triassic to Miocene stocks. The paleozoic rocks has a characteristic thin skinned structure with East transport direction and remarcabie tangential shortenning. In the Andean rocks two tectonostratigraphic grous can be also defin ed: a mesozoic preorogenic sequence linked with extensionaltectonic event, and a tertiary sinorogenic sequence linked with compresional tectonic event.