Cenozoic contractional tectonics in the Fuegian Andes, southernmost South America: a model for the transference of orogenic shortening to the foreland

• Autores: Torres Carbonell, Pablo Juan; Dimieri, Luis Vicente
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: CENTRAL BELT; THRUST FOLD BELT; SHORTENING TRANSFERENCE; CRUSTAL DUPLEX; FUEGIAN ANDES
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The Fuegian thrust-fold belt has been subjected to significant shortening during the Cenozoic. Although contemporaneous shortening and uplift was also recognized in the Fuegian Andes central belt (hinterland), previous studies stated that most of that deformation developed out-of-sequence with the thrust-fold belt and hence did not contribute to its shortening. Therefore, no suitable geometric and kinematic model has been proposed for the mechanism that links deformation in both domains. Here we address the style and timing of the younger (Late Cretaceous-Paleogene) structures of the central belt and the structural evolution of the thrust-fold belt, based on published and own data. We reinterpret the style of the central belt structures, proposing a new model in which all the shortening in the foreland cover was caused by basement thrusting in the central belt. We postulate that the basement was involved in a regional-scale duplex whose roof thrust was the décollement of the thin-skinned thrust-fold belt. Therefore, the total slip transferred through the roof thrust accounted for the shortening in the cover rocks. The basement duplex incorporated the underthrust crust from the footwall of the orogenic wedge through forward propagation, in sequence with the thrust-fold belt from the Late Cretaceous to the Miocene.
Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;
Fil: Dimieri, Luis Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Instituto Geológico del Sur; Argentina;