Synsedimentary broken-foreland tectonics during the Paleogene in the Andes of NW Argentine: new evidence from regional to centimetre-scale deformation features

MONTERO, C.; DEL PAPA, C; HONGN, F.; STRECKER, M.; ARAMAYO, A.

BASIN RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 30 p. 142 - 159

0950-091X

Unravelling the spatiotemporal evolution ofthe Cenozoic Andean (Altiplano-Puna) platean has been one of the most intriguing problems of South American geology. Despite a number of investigations, the early defonnation and uplift history of this area remained largely enigmatic. This paper analyses the Paleogene tectono-sedimentary history of the Casa Grande Basin, in th.e present-day transitionmne between the northem sector of the Puna Platean and the northern part of the Argentine Eastem Cordillera. Our detailed mapping of synsedimentary structures records the onset of regional contractional deformation during the middle Eocene, revealing reactivation of Cretaceous extensional structures and the development of doubly vergent thrusts. This is in agreement with records from other southem parts of the Puna Platea.u and the Eastern Cordillera. These observations indicate the existence of an Eocene broken foreland setting within the region, characterizcd by low-lying compressional basins and ranges with spatially disparate sectors of deformation, which was subsequently subjected to regional uplift resulting in the attainment of present-day elevations during the Neogene.