A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate

A gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The...

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Main Authors: Mario E. Gimenez, Carla Braitenberg, M. Patricia Martinez, Antonio Introcaso
Format: Article
Language:English
Published: Wiley 2009-01-01
Series:International Journal of Geophysics
Online Access:http://dx.doi.org/10.1155/2009/607458
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author Mario E. Gimenez
Carla Braitenberg
M. Patricia Martinez
Antonio Introcaso
author_facet Mario E. Gimenez
Carla Braitenberg
M. Patricia Martinez
Antonio Introcaso
author_sort Mario E. Gimenez
collection DOAJ
description A gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The comparison reveals discrepancies between the gravity Moho depths and those obtained from seismological investigations (CHARGE project), the latter giving deeper values than those resulting from the gravimetric inversion. These discrepancies are attenuated when the positive gravimetric effect of the Nazca plate is considered. Nonetheless, a small residuum of about 5 km remains beneath the Cuyania terrane region, to the east of the main Andean chain. This residuum could be gravimetrically justified if the existence of a high density or eclogitized portion of the lower crust is considered. This result differed from the interpretations from Project “CHARGE” which revealed that the entire inferior crust extending from the Precordillera to the occidental “Sierras Pampeanas” could be “eclogitized”. In this same sector, we calculated the effective elastic thickness (Te) of the crust. These results indicated an anomalous value of Te = 30 km below the Cuyania terrane. This is further conclusive evidence of the fact that the Cuyania terrane is allochthonous, for which also geological evidences exist.
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spelling doaj-art-1cfbe551ea1f41b882caacac50bbfc232025-08-20T03:54:51ZengWileyInternational Journal of Geophysics1687-885X1687-88682009-01-01200910.1155/2009/607458607458A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca PlateMario E. Gimenez0Carla Braitenberg1M. Patricia Martinez2Antonio Introcaso3CONICET, Universidad Nacional de San Juan, IGSV-Métodos Potenciales, San Juan CP. 5400, ArgentinaDepartment of Earth Sciences, University Trieste, Via Weiss 1, 34100 Trieste, ItalyCONICET, Universidad Nacional de San Juan, IGSV-Métodos Potenciales, San Juan CP. 5400, ArgentinaCONICET, Universidad Nacional de Rosario, Rosario CP. 2000, ArgentinaA gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The comparison reveals discrepancies between the gravity Moho depths and those obtained from seismological investigations (CHARGE project), the latter giving deeper values than those resulting from the gravimetric inversion. These discrepancies are attenuated when the positive gravimetric effect of the Nazca plate is considered. Nonetheless, a small residuum of about 5 km remains beneath the Cuyania terrane region, to the east of the main Andean chain. This residuum could be gravimetrically justified if the existence of a high density or eclogitized portion of the lower crust is considered. This result differed from the interpretations from Project “CHARGE” which revealed that the entire inferior crust extending from the Precordillera to the occidental “Sierras Pampeanas” could be “eclogitized”. In this same sector, we calculated the effective elastic thickness (Te) of the crust. These results indicated an anomalous value of Te = 30 km below the Cuyania terrane. This is further conclusive evidence of the fact that the Cuyania terrane is allochthonous, for which also geological evidences exist.http://dx.doi.org/10.1155/2009/607458
spellingShingle Mario E. Gimenez
Carla Braitenberg
M. Patricia Martinez
Antonio Introcaso
A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
International Journal of Geophysics
title A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
title_full A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
title_fullStr A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
title_full_unstemmed A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
title_short A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate
title_sort comparative analysis of seismological and gravimetric crustal thicknesses below the andean region with flat subduction of the nazca plate
url http://dx.doi.org/10.1155/2009/607458
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