Paleozoic to Pliocene evolution of the Andean retroarc between 26 and 28°S : interactions between tectonics climate and upper plate architecture Interactions and feedbacks between tectonics climate and upper plate architecture control basin geometry relief and depositional systems. The Andes is part of a longlived continental margin characterized by multiple tectonic cycles which have strongly modified the Andean upper plate architecture. In the Andean retroarc spatiotemporal variations in the structure of the upper plate and tectonic regimes have resulted in marked along strike variations in basin geometry stratigraphy deformational style and mountain belt morphology. These along strike variations include high elevation plateaus (Altiplano and Puna) associated with a thin skin fold and thrust belt and thick skin deformation in broken foreland basins such as the Santa Barbara system and the Sierras Pampeanas. At the confluence of the Puna Plateau the Santa Barbara system and the Sierras Pampeanas major along strike changes in upper plate architecture mountain belt morphology basement exhumation and deformation style can be recognized. I have used a source to sink ...