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In the Cuesta del Rahue area, located in the Precordillera Neuquina (northern Argentine Patagonia), late Paleozoic turbiditic rocks with maximum depositional age of ca. 389 Ma were affected by three orogenic events. The oldest orogenic event is the Chanic orogeny (Late Devonian–early Carboniferous) that is characterized by folds with NNE vergence. This deformation is developed in low-grade to very low-grade metamorphic conditions, which allowed the development of a slaty/rough cleavage. The main Chanic structure is an asymmetric fold with a large normal limb tilted by the more recent orogenic events. The characteristics of the deformation and metamorphism allows us to assign the Cuesta del Rahue outcrop to the external hinterland of the western wedge of the Chanic orogen. Early to late Carboniferous igneous rocks intruded the Paleozoic rocks of the Cuesta del Rahue area and crosscut the Chanic structures. After the Chanic orogeny, the Gondwanan orogeny (late Carboniferous–early Permian) took place. The main structures of the Gondwanan orogen are thrust and related folds with SSW vergence that fold the large Chanic normal limb and also affect Carboniferous igneous rocks. The Gondwanan deformation was developed under non-metamorphic conditions, and Permian igneous rocks crosscut the Gondwanan structures. Mesozoic regional extension related to the beginning of the Andean cycle and the formation of the Neuquén Basin gave rise to normal faults and small-scale extensional folds. Finally, the Andean orogeny, developed during the Cenozoic in the study area, also affected the Cuesta del Rahue Paleozoic rocks, with the development of compressional structures related to the Aluminé thrust and fold belt. The main Andean structure in the study area is the NW–SE Rahue fault, which links the E–W Piedra Santa tear fault with the NNE–SSW Catán Lil reverse fault. The Rahue fault has a SW tectonic transport direction. It uplifted the Cuesta del Rahue area and placed Paleozoic rocks on top of Mesozoic and Cenozoic rocks. The Piedra Santa fault partially reactivated the Huincul right-lateral and left-lateral Chanic transverse faults that define the southern end of the doubly vergent Chanic orogen, giving rise to the current Huincul lineament. • New insights on the evolution of the Paleozoic basement of the Andes in the southern end of the Cuyo Sector are presented. • In the Cuesta del Rahue outcrop the Paleozoic basement is a turbiditic succession, Middle to Late Devonian in age. • The Cuesta del Rahue is located on the southern end of the western wedge of the Chanic orogen. • The Paleozoic rocks were deformed by the late Paleozoic Chanic and Gondwanan orogenies and the Cenozoic Andean orogeny. • Th Huincul lineament is a wrench fault, limiting by the south the Chanic orogen, partially reactivated during the Gondwanan and Andean orogenies. [ABSTRACT FROM AUTHOR]

During the late Carboniferous–middle Permian, the basement of the Chilean Coastal Cordillera was deformed by the Gondwanan Orogeny, developed by the subduction of the Paleo-Pacific plate under Gondwana from the early Carboniferous. In the Maule sector (35.4°S), the following metamorphic rock units are distinguished: (i) Western Series, formed by metapelites, metabasites, metacherts, metaconglomerates, and marbles, mixed in a subduction channel, with probably ages between the Cambrian and the Carboniferous; (ii) Eastern Series, consisting of metasediments of a fore-arc basin, Carboniferous in age. In the Eastern Series two units are recognized in terms of lithology and deformation style: the Eastern Pelitic Series and the Eastern Sandy Series. Three Gondwanan deformation episodes have been distinguished, affecting both series unequaly. In the Western Series, D1 structures consist of a foliation (S 1) developed under high-pressure and low-temperature conditions, while in the Eastern Series it comprise tight east-verging folds, with the associated S 1 developed under low PT metamorphic conditions (greenschist facies). D2 structures are only present in the Western Series and Eastern Pelitic Series and represent the exhumation of the accretionary prism and its emplacement to the east over the fore-arc basin, with the development of east-verging recumbent folds and a thick shear-zone. Difficulties in the propagation of the deformation by the presence of the Coastal Batholith to the east led to the development of the D3 deformation event, only well developed in the Eastern Sandy Series, and represented by the Los Tablones Back-thrust and associated folds, as well as N–S open right folds formed under low PT metamorphic conditions. • New data on the lithology, structure and metamorphism of the Paleozoic rocks of the Chilean Coastal Range are presented. • Paleozoic rocks of the Maule River were deformed during the Gondwana orogeny under different metamorphic conditions • The Western Series deformed in HP metamorphic conditions during D1 in the subduction channel and was exhumed by an east-directed thrust during D2 • Structures D1, D2 and D3 of the Oriental Series were developed under LP-LT metamorphic conditions. The D1 and D2 have East vergence and the D3 West [ABSTRACT FROM AUTHOR]