Variable structural controls through time in the Southern Central Andes (~36°S)

The Southern Central Andes at 36°S have been recognized as an orogenic belt where contraction, accommodated mainly by basement structures, is associated with the inversion of a Late Triassic-Early Jurassic extensional detachment. Based on a structural cross-section, constrained by field data, 2D sei...

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Autores principales:	Orts, Dario Leandro, Folguera, Andrés, Ramos, Victor Alberto
Publicado:	2012
Materias:	Argentina Brittle-ductile transitions Central Andes Foreland basin Malargüe fold and thrust belt Orogenic front Tectonic inversion basement rock deformation extension fold and thrust belt foreland basin geochronology gravity anomaly orogenic belt slip structural geology subduction tectonic evolution upper crust Andes Cordillera Malargue Mendoza Paraguay
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07187092_v39_n2_p220_Orts http://hdl.handle.net/20.500.12110/paper_07187092_v39_n2_p220_Orts
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_07187092_v39_n2_p220_Orts
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spelling	paper:paper_07187092_v39_n2_p220_Orts2023-06-08T15:43:14Z Variable structural controls through time in the Southern Central Andes (~36°S) Orts, Dario Leandro Folguera, Andrés Ramos, Victor Alberto Argentina Brittle-ductile transitions Central Andes Foreland basin Malargüe fold and thrust belt Orogenic front Tectonic inversion basement rock deformation extension fold and thrust belt foreland basin geochronology gravity anomaly orogenic belt slip structural geology subduction tectonic evolution upper crust Andes Argentina Cordillera Malargue Mendoza Paraguay The Southern Central Andes at 36°S have been recognized as an orogenic belt where contraction, accommodated mainly by basement structures, is associated with the inversion of a Late Triassic-Early Jurassic extensional detachment. Based on a structural cross-section, constrained by field data, 2D seismic and bore-hole information, and the processing of Bouger anomalies, we propose a polyphasic tectonic evolution. In the westernmost sector, along the axis of the Cordillera, NW to NNW basement structures were inverted, being a first order control in the generation of frontal narrow N-trending thin-skinned belts. This slip transfer is controlled by the Late Jurassic main detachment. These structures have low gravity anomalies that cross obliquely the main Andean trend. East of this inversion domain, beneath the frontal thin-skinned belts, seismic information reveals that Late Triassic wedge-like depocenters did not experience substantial inversion. To the east double-vergent basement blocks define the Andean emergent orogenic front at these latitudes. These contractional structures truncate gravity anomalies defined by basement discontinuities, indicating that they are not related to tectonic inversion, in contraposition to the westernmost domain. Two contractional phases were distinguished. The oldest is Late Cretaceous in age, as inferred from onlap relations in Upper Cretaceous strata identified in seismic lines. These successions have a maximum age of 97 Ma as inferred by U-Pb in detrital zircons published in previous studies in the area. Contrastingly, the easternmost sector was mainly deformed in Late Miocene times as inferred from less than 18 Ma old synorogenic deposits. Moreover, contractional mechanisms varied through time for each specific sector. While Late Cretaceous contractional tectonics was generated by tectonic inversion and subordinate thin-skinned deformation, it is proposed that Late Miocene deformation was controlled mainly by brittle-ductile transitions at the upper crust with no major influence of previous structures. This fact can be explained by a higher thermal flux achieved in the retroarc area in the last 17 Ma due to the eastward arc expansion during a shallow subduction regime. Fil:Orts, D.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Folguera, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ramos, V.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07187092_v39_n2_p220_Orts http://hdl.handle.net/20.500.12110/paper_07187092_v39_n2_p220_Orts
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Argentina Brittle-ductile transitions Central Andes Foreland basin Malargüe fold and thrust belt Orogenic front Tectonic inversion basement rock deformation extension fold and thrust belt foreland basin geochronology gravity anomaly orogenic belt slip structural geology subduction tectonic evolution upper crust Andes Argentina Cordillera Malargue Mendoza Paraguay
spellingShingle	Argentina Brittle-ductile transitions Central Andes Foreland basin Malargüe fold and thrust belt Orogenic front Tectonic inversion basement rock deformation extension fold and thrust belt foreland basin geochronology gravity anomaly orogenic belt slip structural geology subduction tectonic evolution upper crust Andes Argentina Cordillera Malargue Mendoza Paraguay Orts, Dario Leandro Folguera, Andrés Ramos, Victor Alberto Variable structural controls through time in the Southern Central Andes (~36°S)
topic_facet	Argentina Brittle-ductile transitions Central Andes Foreland basin Malargüe fold and thrust belt Orogenic front Tectonic inversion basement rock deformation extension fold and thrust belt foreland basin geochronology gravity anomaly orogenic belt slip structural geology subduction tectonic evolution upper crust Andes Argentina Cordillera Malargue Mendoza Paraguay
description	The Southern Central Andes at 36°S have been recognized as an orogenic belt where contraction, accommodated mainly by basement structures, is associated with the inversion of a Late Triassic-Early Jurassic extensional detachment. Based on a structural cross-section, constrained by field data, 2D seismic and bore-hole information, and the processing of Bouger anomalies, we propose a polyphasic tectonic evolution. In the westernmost sector, along the axis of the Cordillera, NW to NNW basement structures were inverted, being a first order control in the generation of frontal narrow N-trending thin-skinned belts. This slip transfer is controlled by the Late Jurassic main detachment. These structures have low gravity anomalies that cross obliquely the main Andean trend. East of this inversion domain, beneath the frontal thin-skinned belts, seismic information reveals that Late Triassic wedge-like depocenters did not experience substantial inversion. To the east double-vergent basement blocks define the Andean emergent orogenic front at these latitudes. These contractional structures truncate gravity anomalies defined by basement discontinuities, indicating that they are not related to tectonic inversion, in contraposition to the westernmost domain. Two contractional phases were distinguished. The oldest is Late Cretaceous in age, as inferred from onlap relations in Upper Cretaceous strata identified in seismic lines. These successions have a maximum age of 97 Ma as inferred by U-Pb in detrital zircons published in previous studies in the area. Contrastingly, the easternmost sector was mainly deformed in Late Miocene times as inferred from less than 18 Ma old synorogenic deposits. Moreover, contractional mechanisms varied through time for each specific sector. While Late Cretaceous contractional tectonics was generated by tectonic inversion and subordinate thin-skinned deformation, it is proposed that Late Miocene deformation was controlled mainly by brittle-ductile transitions at the upper crust with no major influence of previous structures. This fact can be explained by a higher thermal flux achieved in the retroarc area in the last 17 Ma due to the eastward arc expansion during a shallow subduction regime.
author	Orts, Dario Leandro Folguera, Andrés Ramos, Victor Alberto
author_facet	Orts, Dario Leandro Folguera, Andrés Ramos, Victor Alberto
author_sort	Orts, Dario Leandro
title	Variable structural controls through time in the Southern Central Andes (~36°S)
title_short	Variable structural controls through time in the Southern Central Andes (~36°S)
title_full	Variable structural controls through time in the Southern Central Andes (~36°S)
title_fullStr	Variable structural controls through time in the Southern Central Andes (~36°S)
title_full_unstemmed	Variable structural controls through time in the Southern Central Andes (~36°S)
title_sort	variable structural controls through time in the southern central andes (~36°s)
publishDate	2012
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07187092_v39_n2_p220_Orts http://hdl.handle.net/20.500.12110/paper_07187092_v39_n2_p220_Orts
work_keys_str_mv	AT ortsdarioleandro variablestructuralcontrolsthroughtimeinthesoutherncentralandes36s AT folgueraandres variablestructuralcontrolsthroughtimeinthesoutherncentralandes36s AT ramosvictoralberto variablestructuralcontrolsthroughtimeinthesoutherncentralandes36s
_version_	1768545789431250944

Variable structural controls through time in the Southern Central Andes (~36°S)

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