Excursion to NW Argentina
The history of the southern central Andes of Argentina, including Earth’s second largest orogenic plateau (Puna Plateau) and adjacent intermontane basins and ranges of the Eastern Cordillera, the Santa Barbara System, and the northern Sierras Pampeanas, impressively documents the effects of tectonics and climate on protracted orogenic evolution in a non-collisional mountain belt. In particular, the development of orographic barriers with pronounced rainfall gradients, superposed ongoing tectonism, and volcanism, mass movements, and a variety of voracious erosion processes have created a complex environment that allows analyzing landscape evolution and the level of tectonic activity in a Cenozoic mountain belt at various timescales. The importance of better understanding surface processes in the Andes and their geodynamic, structural, and climatic boundary conditions is highlighted by the interplay between tectonic deformation and the effects of changing regional to global Cenozoic climate conditions and ensuing changes in the surface-process regime. This part of the analysis involves timescales of hundred thousands to millions of years. On much shorter timescales spanning several thousand to ten thousand years, the synergistic effects of climate variability and active tectonics are often less clear in many orogens. However, the Andes provide a unique environment to address these challenging problems. The field school will introduce the tectonic, climatic, and sedimentary evolution of the southern central Andes and the adjacent foreland areas. The course will track the geological evolution from a former unrestricted foreland-basin setting to a broken foreland with disparate, unsystematic range uplifts (Sierras Pampeanas, Santa Barbara System). These broken-foreland sectors transition northward into a foreland fold-and-thrust belt with a well-defined eastward-advancing deformation front. The participants will be familiarized with the principal fault systems in these tectonic provinces, and their kinematic evolution, present-day and past sedimentary environments, and long-term impacts on climate change will be analyzed in detail.