Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas

The Nazca Plate subducting beneath the South American Plate has strongly influenced Cenozoic mountain growth in western Argentina and Chile sectors (32-34°S; 70-66°W). At these latitudes, the Pampean flat slab has induced the development of prominent mountain systems such as the Frontal Cordillera,...

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Autores principales: Sánchez, M., Lince Klinger, F., Martinez, M.P., Alvarez, O., Ruiz, F., Weidmann, C., Folguera, A.
Formato: SER
Materias:
crustal shortening
deformation mechanism
foreland basin
Nazca plate
slab
subduction zone
topography
transition zone
upper crust
Andes
Argentina
Precordillera
Sierras Pampeanas
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_03058719_v399_n_p167_Sanchez
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_03058719_v399_n_p167_Sanchez2023-10-03T15:22:04Z Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas Sánchez, M. Lince Klinger, F. Martinez, M.P. Alvarez, O. Ruiz, F. Weidmann, C. Folguera, A. crustal shortening deformation mechanism foreland basin Nazca plate slab subduction zone topography transition zone upper crust Andes Argentina Precordillera Sierras Pampeanas The Nazca Plate subducting beneath the South American Plate has strongly influenced Cenozoic mountain growth in western Argentina and Chile sectors (32-34°S; 70-66°W). At these latitudes, the Pampean flat slab has induced the development of prominent mountain systems such as the Frontal Cordillera, the Precordillera, and the associated Sierras Pampeanas in the eastwards foreland region. Through a gravity study from the Frontal Cordillera to the Sierras Pampeanas region between 32 and 34°S, we delimit a series of geological structures that are accommodating shortening in the upper crust and others of regional and subsurface development, without any clearly defined mechanics of deformation. Additionally, through an isostatic residual anomaly map based on the Airy-Heiskanen local compensation model, we obtain a decompensative gravity anomaly map that highlights anomalous gravity sources emplaced in the upper crust, related to known geological structures. In particular, by applying the Tilt method which enhances the gravity anomalies, the NW-trending Tunuyan Lineament is depicted south of 33.4°S following previous proposals. Using the decompensative gravity anomaly, two profiles were modelled through the northern sector of the study area using deep seismic refraction lines, borehole data and geological information as constraints. These density models of the upper crust of this structurally complex area accurately represent basin geometries and basement topography and constitute a framework for future geological analysis. © 2015 The Geological Society of London. Fil:Folguera, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. SER info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03058719_v399_n_p167_Sanchez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic crustal shortening
deformation mechanism
foreland basin
Nazca plate
slab
subduction zone
topography
transition zone
upper crust
Andes
Argentina
Precordillera
Sierras Pampeanas
spellingShingle crustal shortening
deformation mechanism
foreland basin
Nazca plate
slab
subduction zone
topography
transition zone
upper crust
Andes
Argentina
Precordillera
Sierras Pampeanas
Sánchez, M.
Lince Klinger, F.
Martinez, M.P.
Alvarez, O.
Ruiz, F.
Weidmann, C.
Folguera, A.
Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
topic_facet crustal shortening
deformation mechanism
foreland basin
Nazca plate
slab
subduction zone
topography
transition zone
upper crust
Andes
Argentina
Precordillera
Sierras Pampeanas
description The Nazca Plate subducting beneath the South American Plate has strongly influenced Cenozoic mountain growth in western Argentina and Chile sectors (32-34°S; 70-66°W). At these latitudes, the Pampean flat slab has induced the development of prominent mountain systems such as the Frontal Cordillera, the Precordillera, and the associated Sierras Pampeanas in the eastwards foreland region. Through a gravity study from the Frontal Cordillera to the Sierras Pampeanas region between 32 and 34°S, we delimit a series of geological structures that are accommodating shortening in the upper crust and others of regional and subsurface development, without any clearly defined mechanics of deformation. Additionally, through an isostatic residual anomaly map based on the Airy-Heiskanen local compensation model, we obtain a decompensative gravity anomaly map that highlights anomalous gravity sources emplaced in the upper crust, related to known geological structures. In particular, by applying the Tilt method which enhances the gravity anomalies, the NW-trending Tunuyan Lineament is depicted south of 33.4°S following previous proposals. Using the decompensative gravity anomaly, two profiles were modelled through the northern sector of the study area using deep seismic refraction lines, borehole data and geological information as constraints. These density models of the upper crust of this structurally complex area accurately represent basin geometries and basement topography and constitute a framework for future geological analysis. © 2015 The Geological Society of London.
format SER
author Sánchez, M.
Lince Klinger, F.
Martinez, M.P.
Alvarez, O.
Ruiz, F.
Weidmann, C.
Folguera, A.
author_facet Sánchez, M.
Lince Klinger, F.
Martinez, M.P.
Alvarez, O.
Ruiz, F.
Weidmann, C.
Folguera, A.
author_sort Sánchez, M.
title Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
title_short Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
title_full Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
title_fullStr Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
title_full_unstemmed Geophysical characterization of the upper crust in the transitional zone between the Pampean flat slab and the normal subduction segment to the south (32-34°S): Andes of the Frontal Cordillera to the Sierras Pampeanas
title_sort geophysical characterization of the upper crust in the transitional zone between the pampean flat slab and the normal subduction segment to the south (32-34°s): andes of the frontal cordillera to the sierras pampeanas
url http://hdl.handle.net/20.500.12110/paper_03058719_v399_n_p167_Sanchez
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AT linceklingerf geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
AT martinezmp geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
AT alvarezo geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
AT ruizf geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
AT weidmannc geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
AT folgueraa geophysicalcharacterizationoftheuppercrustinthetransitionalzonebetweenthepampeanflatslabandthenormalsubductionsegmenttothesouth3234sandesofthefrontalcordilleratothesierraspampeanas
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