The Andean thrust front in the Cerros Penitentes and Visera (High Cordillera of Mendoza): chronological and cartographic aspects

Abstract

The finding of an important marine invertebrate fauna of Upper Tithonian age at the shoulders of the Penitentes hill, in the basal carbonatic sequence of the first Andean wedge confirms the tectonic logic of a detachment of this unit at the level of the Yeso Principal. This allows invalidating certain lithostratigraphic correlations and paleogeographic sketches ascribed to the La Manga Formation. On the other hand, the analysis of some key sections around the Penitentes hill area between the Quebrada de Vargas and the Cerro Visera, allows presenting a tectonic reinterpretation of the sector. This is based on the recognition and differentiation of the main Tertiary units represented in the area by the Penitentes Conglomerates (Early Miocene) and the Santa María Agglomerates (Late Miocene) in a mutual relationship very similar to that previously described at the north of Puente del Inca. The study show interferences, in a polyphasic context, between the reactivations of the thinskinned Penitentes overthrust and a thick skinned frontal thrust which repeats the Tertiary sequence. The unconformity between the Tertiary sequences and the emplacement of a Malm klippe above the Penitentes Conglomerates of the Cerro Visera syncline, lead to ascribe certain importance to the final phase of the Early Miocene.