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The Neuquén Embayment, which developed along the eastern foothills of the southern Central Andes, has a complex history of intraplate deformation. The Paleozoic basement fabrics exerted a major influence in Mesozoic and Cenozoic deformation. The most important feature is an E-W–striking fault system that is related to a late Paleozoic fabric and is associated with the Huincul basement high, which truncates the basin. This fabric is interpreted as being the result of the accretion of the Patagonia terrane with Gondwana during the Early Permian. Two-dimensional (2D) and three-dimensional (3D) seismic coverage and subsurface information identify different sectors in the Neuquén Embayment that record alternating episodes of contraction and extension during the Jurassic and Cretaceous. The deformation history east of the thrust front of the Agrio fold-and-thrust belt is characterized by periods of (1) transpression and almost orthogonal contraction to the continental margin, (2) extension, and (3) relative quiescence, which alternates in different sectors. The earliest shortening occurred in the Early Jurassic when the main stress was oriented in the N-NW sector. The stress rotated to the northwest up to Valanginian times, when a more orthogonal orientation to the continental margin became dominant and prevailed after the Cenomanian. After a period of quiescence in the Neuquén Embayment associated with very oblique subduction during the Paleogene, the final contractional deformation took place in the late Miocene, with a west-east orientation of the main stress, and was followed by Pliocene extension.

The changing stress patterns correlate with differences in convergence vectors between the Aluk, Farallon, and Nazca oceanic plates and the Gondwana or South American continental plates. The Aluk stage from the Jurassic to the Valanginian was characterized by tectonic inversion that is shown by shortening and right-lateral strike-slip structures that are concentrated in the Huincul system and more subtle deformation in the Chihuidos and Entre Lomas systems. The early Farallon stage was distinguished by reduced inversion and displacement in the Huincul system and a general retreat of deformation after the Valanginian. The change to late Farallon stage was characterized by a prominent tectonic inversion of the Entre Lomas system, which resulted from the inception of the formation of the Agrio fold-and-thrust belt in the retroarc area. This belt developed during most of the Late Cretaceous, when the embayment showed a general quiescence. The Nazca stage was characterized by the main episode of uplift, tectonic inversion of the older half-grabens, and important strike-slip faulting that was followed by local collapse of some structures during the Pliocene.

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