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| Format: | Artículo científico |
| Sprache: | en |
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Servicio Nacional de Geología y Minería
2018
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| Online-Zugang: | https://www.redalyc.org/articulo.oa?id=173955659007 https://www.redalyc.org/journal/1739/173955659007/ https://www.redalyc.org/journal/1739/173955659007/html/ https://www.redalyc.org/journal/1739/173955659007/173955659007.epub https://www.redalyc.org/journal/1739/173955659007/movil https://doi.org/10.5027/andgeoV45n2-3049 |
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- The structure of the northern Agrio fold and thrust belt (37°30’ S), Neuquén Basin, Argentina Fernando Lebinson Martín Turienzo Natalia Sánchez Vanesa Araujo María Celeste D’Annunzio Luis Dimieri Ciencias de la Tierra sections Thick and thin Balanced cross Thrust systems skinned structures The Agrio fold and thrust belt is a thick-skinned orogenic belt developed since Late Cretaceous in response to the convergence between the Nazca and South American plates. The integration of new structural field data and seismic line interpretation allowed us to create two balanced cross-sections, which help to analyse the geometry of both thick and thin-skinned structures, to calculate the tectonic shortenings and finally to discuss the main mechanisms that produced this fold and thrust belt. The predominantly NNW-SSE structures show varying wavelengths, and can be classified into kilometer-scale first order basement involved structures and smaller second, third and fourth order fault-related folds in cover rocks with shallower detachments. Thick-skinned structures comprise fault-bend folds moving into the sedimentary cover, mainly along Late Jurassic evaporites, which form basement wedges that transfer the deformation to the foreland. Thus, shortenings in both basement and cover rocks must be similar and consequently, by measuring the contraction accounted for thin-skinned structures, is possible to propose a suitable model for the thick skinned deformation. The balanced cross-sections indicate shortenings of 11.2 km (18%) for the northern section and 10.9 km (17.3%) for the southern section. These values are different from the shortenings established by previous works in the region, reflecting differences in the assumed model to explain the basement-involved structures. According to our interpretation, the structural evolution of this fold and thrust belt was controlled by major basement-involved thrust systems with subordinate influence of inversion along pre-existing normal faults during the Andean compression. 2018 artículo científico 0718-7092 https://www.redalyc.org/articulo.oa?id=173955659007 https://www.redalyc.org/journal/1739/173955659007/ https://www.redalyc.org/journal/1739/173955659007/html/ https://www.redalyc.org/journal/1739/173955659007/173955659007.epub https://www.redalyc.org/journal/1739/173955659007/movil https://doi.org/10.5027/andgeoV45n2-3049 en http://www.redalyc.org/revista.oa?id=1739 Andean Geology application/pdf Servicio Nacional de Geología y Minería Andean Geology (Chile) Num.2 Vol.45