Abstract

HONGN, Fernando et al. Cretaceous-Cenozoic tectonic inversion and reactivation in Northwestern Argentina: Influence of Neoproterozoic-Lower Paleozoic basement heterogeneities. Rev. Asoc. Geol. Argent. [online]. 2010, vol.66, n.1-2, pp.38-53. ISSN 0004-4822.

The Neoproterozoic-Lower Paleozoic basement structural features have influenced in different ways the development of later both extensional Cretaceous and contractional Cenozoic structures. Tectonic inversion of normal faults related to the Cretaceous rift has been frequently addressed as the main mechanism for explaining double-vergent and retrovergent structures in the hinterland of the Andean orogen in northwestern Argentina. This paper proposes that basement structures played a primary role in the nucleation of both Cretaceous normal faults showing Cenozoic tectonic inversion and Cenozoic reverse faults. A regional section between the Domeyko Cordillera (Chile) and the Santa Bárbara System (nearly at 24º-25ºSL) shows portions with opposite Cenozoic vergence, each one related to different controls made by previous structures. The inversion of Mesozoic rift-related faults mainly influenced the geometry and vergence of the Cenozoic structures linked to Andean shortening in the Domeyko Cordillera, in the Calchaquí Valleys region and in the Santa Bárbara System. Reactivation of structures and heterogeneities formed during the Neoproterozoic-lower Paleozoic tectonic evolution of the basement controlled the Andean contractional structures in the Puna. Reactivation of Neoproterozoic-lower Paleozoic basement heterogeneities not only contributes to changes in attitude and vergence but also to the irregular time distribution showed by the Andean shortening since many of the reactivated or inverted (positive and negative inversion) structures record superposed movements from the Cretaceous up to the Quaternary.

Keywords : Tectonic Inversion; Reactivation; Cretaceous Rift; Andean Shortening; NW-Argentina.

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