Structure of the High Andes of Mendoza along the Piuquenes and Portillo Passes

GIAMBIAGI, L., TUNIK, M., RAMOS, V. Y GODOY, E.

Revista Asociación Geológica Argentina

Asociación Geológica Argentina

Lugar: Buenos Aires; Año: 2009 vol. 61 p. 43 - 54

0004-4822

The most complete traverse of the High Andean Cordillera performed by Darwin in 1835 is examined based on the present knowledge of the Principal and Frontal Cordilleras at these latitudes. Through a discussion of the complex stratigraphy of the region, its imbricated structure of different thrust sheets of the Aconcagua fold and thrust belt, as well as the intermontaneous foreland Tunuyán Basin we weight the pioneer observations of Darwin. He recognized an old metamorphic basement, the granitoids and volcanic sequences of late Paleozoic to Triassic age, established the Cretaceous age of the marine successions and the conglomeratic deposits associated with the uplift of the Cordillera. His most significant contribution to the tectonic evolution of the region is associated with the recognition of the uplift ages of the different mountain ranges that took place after the Cretaceous. Based on the study of the clast provenance of the synorogenic deposits Darwin was able to recognize the uplift of the Cordillera Principal, followed by the Cordillera Frontal uplift, which through a series of different pulses obtained its present elevation in more recent times. The present data set of this sector of the Andean Cordillera confirms his observations. The analysis performed by Darwin is one of the first to recognize that in an orogenic system the uplift sequence of the structure of the mountains starts in the hinterland from where it progresses to the foreland, taking as a magnificent example the mountain ranges recognized in the High Andean Cordillera.