Tectono-stratigraphic evolution of inter-montane basins related to forearc tectonic settings using the Chilean Pre-Andean Depression of the Central Andes as a case study

Abstract

The structural architecture and the tectonic evolution of the western Central Andes remains an open debate due to the absence of key geological constrains such as the structural styles in subsurface, ages of the geological units, and age of deformation. A proper understanding of these elements is key to assess the interplay between structure, growth mechanism and timing of deformation in any orogenic belt. Moderate amount of exhumation and Cenozoic volcanism that has supplied datable materials to the inter-montane basins make the Central Andes of northern Chile is one of the most attractive natural laboratory in South America to analyze this interplay. In particular, the Pre-Andean Depression and their associated inter-montane basins represent privileged places to study the effects of the Andean deformation in the western Central Andes due to excellent outcrops and existence or industry subsurface information. This scientific project seeks to foster collaboration between the tectonic team at the North Catholic University of Chile and the geochronological team in the University of São Paulo in order to obtain the best concept of the structure and the tectonic evolution of the inter-montane basins that form part of the Chilean Pre-Andean Depression along the Salar de Punta Negras Basins. Previous structural and geochronological interpretations carried out as initial collaboration between both teams (Chile-Brazil) have allowed to propose the hypothesis that inter-montane basins resulted from the Late Cretaceous to Paleocene tectonic inversion of ancient Mesozoic half grabens. To further examine this hypothesis, a multidisciplinary work scheme will be conducted, which include: fieldwork, seismic and structural interpretations, and radiometric age determinations by U-Pb and low-temperature thermochronology methods (apatite fission track and (U-Th)/He in apatite and zircon). This initiative includes the important goal of forming human resources by including the participation of new PhD and ungraduated students, which will strengthen and enlarge our already established scientific network. (AU)