Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)

The Neuquén Group is an Upper Cretaceous continental sedimentary unit exhumed during the latest Miocene contractional phase occurred in the southern Central Andes, allowing a direct field observation and study of the depositional geometries. The identification of growth strata on these units surroun...

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Detalles Bibliográficos
Autores principales:	Fennell, L.M., Folguera, A., Naipauer, M., Gianni, G., Rojas Vera, E.A., Bottesi, G., Ramos, V.A.
Formato:	JOUR
Materias:	Cretaceous deformation deposition exhumation foreland basin Maastrichtian sedimentation sedimentology uranium-lead dating Andes
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_0950091X_v29_n_p51_Fennell
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_0950091X_v29_n_p51_Fennell2023-10-03T15:49:57Z Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S) Fennell, L.M. Folguera, A. Naipauer, M. Gianni, G. Rojas Vera, E.A. Bottesi, G. Ramos, V.A. Cretaceous deformation deposition exhumation foreland basin Maastrichtian sedimentation sedimentology uranium-lead dating Andes The Neuquén Group is an Upper Cretaceous continental sedimentary unit exhumed during the latest Miocene contractional phase occurred in the southern Central Andes, allowing a direct field observation and study of the depositional geometries. The identification of growth strata on these units surrounding the structures of the frontal parts of the Andes, sedimentological analyses and U–Pb dating of detrital components, allowed the definition of a synorogenic unit that coexisted with the uplift of the early Andean orogen since ca. 100 Ma, maximum age obtained in this work, compatible with previous assignments and constrained in the top by the deposition of the Malargüe Group, in the Maastrichtian (ca. 72 Ma). The definition of a wedge top area in this foreland basin system, where growth strata were described, permitted to identify a Late Cretaceous orogenic front and foredeep area, whose location and amplitude contrast with previous hypotheses. This wedge top area was mostly fed from the paleo-Andes with small populations coming from sources in the cratonic area that are interpreted as a recycling in Jurassic and Lower Cretaceous sections, which contrasts with other analyses performed at the foredeep zone that have mixed sources. In particular, Permian sources are interpreted as coming directly from the cores of the basement structures, where Neopaleozoic sections are exposed, next to the synorogenic sedimentation, implying a strong incision in Late Cretaceous times with an exhumation structural level similar to the present. The maximum recognised advance for this Late Cretaceous deformation in the study area is approximately 500 km east of the Pacific trench, which constitutes an anomaly compared with neighbour segments where Late Cretaceous deformations were found considerably retracted. The geodynamic context of the sedimentation of this unit is interpreted as produced under the westward fast moving of South America, colliding with two consecutive mid-ocean ridges during a period of important plate reorganisation. The subduction of young, anhydrous, buoyant lithosphere would have produced changes in the subduction geometry, reflected first by an arc waning/gap and subsequently by an arc migration that coexisted with synorogenic sedimentation. These magmatic and deformational processes would be the product of a shallow subduction regime, following previous proposals, which occurred in Late Cretaceous times, synchronous to the sedimentation of the Neuquén Group. © 2015 The Authors. Basin Research © 2015 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0950091X_v29_n_p51_Fennell
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Cretaceous deformation deposition exhumation foreland basin Maastrichtian sedimentation sedimentology uranium-lead dating Andes
spellingShingle	Cretaceous deformation deposition exhumation foreland basin Maastrichtian sedimentation sedimentology uranium-lead dating Andes Fennell, L.M. Folguera, A. Naipauer, M. Gianni, G. Rojas Vera, E.A. Bottesi, G. Ramos, V.A. Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
topic_facet	Cretaceous deformation deposition exhumation foreland basin Maastrichtian sedimentation sedimentology uranium-lead dating Andes
description	The Neuquén Group is an Upper Cretaceous continental sedimentary unit exhumed during the latest Miocene contractional phase occurred in the southern Central Andes, allowing a direct field observation and study of the depositional geometries. The identification of growth strata on these units surrounding the structures of the frontal parts of the Andes, sedimentological analyses and U–Pb dating of detrital components, allowed the definition of a synorogenic unit that coexisted with the uplift of the early Andean orogen since ca. 100 Ma, maximum age obtained in this work, compatible with previous assignments and constrained in the top by the deposition of the Malargüe Group, in the Maastrichtian (ca. 72 Ma). The definition of a wedge top area in this foreland basin system, where growth strata were described, permitted to identify a Late Cretaceous orogenic front and foredeep area, whose location and amplitude contrast with previous hypotheses. This wedge top area was mostly fed from the paleo-Andes with small populations coming from sources in the cratonic area that are interpreted as a recycling in Jurassic and Lower Cretaceous sections, which contrasts with other analyses performed at the foredeep zone that have mixed sources. In particular, Permian sources are interpreted as coming directly from the cores of the basement structures, where Neopaleozoic sections are exposed, next to the synorogenic sedimentation, implying a strong incision in Late Cretaceous times with an exhumation structural level similar to the present. The maximum recognised advance for this Late Cretaceous deformation in the study area is approximately 500 km east of the Pacific trench, which constitutes an anomaly compared with neighbour segments where Late Cretaceous deformations were found considerably retracted. The geodynamic context of the sedimentation of this unit is interpreted as produced under the westward fast moving of South America, colliding with two consecutive mid-ocean ridges during a period of important plate reorganisation. The subduction of young, anhydrous, buoyant lithosphere would have produced changes in the subduction geometry, reflected first by an arc waning/gap and subsequently by an arc migration that coexisted with synorogenic sedimentation. These magmatic and deformational processes would be the product of a shallow subduction regime, following previous proposals, which occurred in Late Cretaceous times, synchronous to the sedimentation of the Neuquén Group. © 2015 The Authors. Basin Research © 2015 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
format	JOUR
author	Fennell, L.M. Folguera, A. Naipauer, M. Gianni, G. Rojas Vera, E.A. Bottesi, G. Ramos, V.A.
author_facet	Fennell, L.M. Folguera, A. Naipauer, M. Gianni, G. Rojas Vera, E.A. Bottesi, G. Ramos, V.A.
author_sort	Fennell, L.M.
title	Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
title_short	Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
title_full	Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
title_fullStr	Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
title_full_unstemmed	Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)
title_sort	cretaceous deformation of the southern central andes: synorogenic growth strata in the neuquén group (35° 30′–37° s)
url	http://hdl.handle.net/20.500.12110/paper_0950091X_v29_n_p51_Fennell
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Cretaceous deformation of the southern Central Andes: synorogenic growth strata in the Neuquén Group (35° 30′–37° S)

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