Geological structure and crustal shortening of the Andes of South Bolivia and Northwest Argentina

For 10 Ma, the 60-70 km thick crust beneath the Altiplano and the northern Puna has caused a strong plateau uplift. In order to examine, whether crustal thickening was effected by Andean tectonic shortening, we investigated the tectonic structure of the Cordillera Oriental of southern Bolivia and of the northwest Argentine Puna. Our investigations were based on intense studies of stratigraphy and facies of the Ordovician basement, the Cretaceous-Paleocene cover and of Neogene basin infills. A balanced profile across the Cordillera Oriental and new literature data on the Altiplano, the Inter-andean and the Subandean ranges show that the high crustal thickness beneath the Altiplano and the Cordillera Oriental can not be explained by tectonic processes, exclusively.