High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics

In the flat slab region of the South Central Andes (∼31–32°S), geological observations suggest that the regional crustal structure is inherited from the accretion of different terranes during the Ordovician. These structures were later reactivated, first in extension during the Triassic and later in...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Ammirati, J.-B., Pérez Luján, S., Alvarado, P., Beck, S., Rocher, S., Zandt, G.
Formato: JOUR
Materias:
Andean retroarc
body waves
Eclogite
South America
subduction
surface waves
Faulting
Seismic waves
Seismology
Structural geology
Surface waves
Body waves
Eclogites
Tectonics
body wave
crustal structure
deformation mechanism
eclogite
image resolution
Ordovician
regional geology
seismic tomography
seismic velocity
slab
stacking
tectonic setting
Andes
Argentina
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0012821X_v450_n_p29_Ammirati
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_0012821X_v450_n_p29_Ammirati
record_format dspace
spelling todo:paper_0012821X_v450_n_p29_Ammirati2023-10-03T14:10:34Z High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics Ammirati, J.-B. Pérez Luján, S. Alvarado, P. Beck, S. Rocher, S. Zandt, G. Andean retroarc body waves Eclogite South America subduction surface waves Faulting Seismic waves Seismology Structural geology Surface waves Andean retroarc Body waves Eclogites South America subduction Tectonics body wave crustal structure deformation mechanism eclogite image resolution Ordovician regional geology seismic tomography seismic velocity slab stacking subduction tectonic setting Andes Argentina In the flat slab region of the South Central Andes (∼31–32°S), geological observations suggest that the regional crustal structure is inherited from the accretion of different terranes during the Ordovician. These structures were later reactivated, first in extension during the Triassic and later in compression during the Andean uplift since the Miocene. Seismological observations confirmed that those fault structures extend to depth with décollement levels that accommodate current crustal shortening in the region. In order to get better insight on the regional tectonics we computed higher frequency receiver functions (RF) from local slab seismicity of intermediate ∼100 km depth. Using a common conversion point (CCP) stacking method we obtained cross sections showing high vertical resolution crustal structure at the transition between the Precordillera and the Frontal Cordillera. In addition we performed a joint inversion of our high frequency RFs with surface wave data from ambient noise tomography allowing us to constrain absolute seismic wave velocities. Our higher resolution images reveal more structural details down to a depth of 80 km and laterally over the flat slab in good agreement with previous studies. Our results help to better identify very shallow discontinuities in seismic velocities. Recent petrological analyses combined with our high-resolution RF structure correlates with a crustal mafic composition and partial eclogitization in the lower crust. We observe a shift in the crustal structure between the Precordillera (east) and the Frontal Cordillera (west). Regional seismicity and previously determined focal mechanisms superimposed over our images indicate this shifting is a thrust structure extending down to a depth of 40 km. Our results suggest the presence of a master fault between the Cuyania (Western Precordillera) and Chilenia (Frontal Cordillera) terranes that probably accommodates the crustal deformation in the Pampean flat slab region since the Late Ordovician. © 2016 Elsevier B.V. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0012821X_v450_n_p29_Ammirati
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Andean retroarc
body waves
Eclogite
South America
subduction
surface waves
Faulting
Seismic waves
Seismology
Structural geology
Surface waves
Andean retroarc
Body waves
Eclogites
South America
subduction
Tectonics
body wave
crustal structure
deformation mechanism
eclogite
image resolution
Ordovician
regional geology
seismic tomography
seismic velocity
slab
stacking
subduction
tectonic setting
Andes
Argentina
spellingShingle Andean retroarc
body waves
Eclogite
South America
subduction
surface waves
Faulting
Seismic waves
Seismology
Structural geology
Surface waves
Andean retroarc
Body waves
Eclogites
South America
subduction
Tectonics
body wave
crustal structure
deformation mechanism
eclogite
image resolution
Ordovician
regional geology
seismic tomography
seismic velocity
slab
stacking
subduction
tectonic setting
Andes
Argentina
Ammirati, J.-B.
Pérez Luján, S.
Alvarado, P.
Beck, S.
Rocher, S.
Zandt, G.
High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
topic_facet Andean retroarc
body waves
Eclogite
South America
subduction
surface waves
Faulting
Seismic waves
Seismology
Structural geology
Surface waves
Andean retroarc
Body waves
Eclogites
South America
subduction
Tectonics
body wave
crustal structure
deformation mechanism
eclogite
image resolution
Ordovician
regional geology
seismic tomography
seismic velocity
slab
stacking
subduction
tectonic setting
Andes
Argentina
description In the flat slab region of the South Central Andes (∼31–32°S), geological observations suggest that the regional crustal structure is inherited from the accretion of different terranes during the Ordovician. These structures were later reactivated, first in extension during the Triassic and later in compression during the Andean uplift since the Miocene. Seismological observations confirmed that those fault structures extend to depth with décollement levels that accommodate current crustal shortening in the region. In order to get better insight on the regional tectonics we computed higher frequency receiver functions (RF) from local slab seismicity of intermediate ∼100 km depth. Using a common conversion point (CCP) stacking method we obtained cross sections showing high vertical resolution crustal structure at the transition between the Precordillera and the Frontal Cordillera. In addition we performed a joint inversion of our high frequency RFs with surface wave data from ambient noise tomography allowing us to constrain absolute seismic wave velocities. Our higher resolution images reveal more structural details down to a depth of 80 km and laterally over the flat slab in good agreement with previous studies. Our results help to better identify very shallow discontinuities in seismic velocities. Recent petrological analyses combined with our high-resolution RF structure correlates with a crustal mafic composition and partial eclogitization in the lower crust. We observe a shift in the crustal structure between the Precordillera (east) and the Frontal Cordillera (west). Regional seismicity and previously determined focal mechanisms superimposed over our images indicate this shifting is a thrust structure extending down to a depth of 40 km. Our results suggest the presence of a master fault between the Cuyania (Western Precordillera) and Chilenia (Frontal Cordillera) terranes that probably accommodates the crustal deformation in the Pampean flat slab region since the Late Ordovician. © 2016 Elsevier B.V.
format JOUR
author Ammirati, J.-B.
Pérez Luján, S.
Alvarado, P.
Beck, S.
Rocher, S.
Zandt, G.
author_facet Ammirati, J.-B.
Pérez Luján, S.
Alvarado, P.
Beck, S.
Rocher, S.
Zandt, G.
author_sort Ammirati, J.-B.
title High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
title_short High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
title_full High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
title_fullStr High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
title_full_unstemmed High-resolution images above the Pampean flat slab of Argentina (31–32°S) from local receiver functions: Implications on regional tectonics
title_sort high-resolution images above the pampean flat slab of argentina (31–32°s) from local receiver functions: implications on regional tectonics
url http://hdl.handle.net/20.500.12110/paper_0012821X_v450_n_p29_Ammirati
work_keys_str_mv AT ammiratijb highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
AT perezlujans highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
AT alvaradop highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
AT becks highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
AT rochers highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
AT zandtg highresolutionimagesabovethepampeanflatslabofargentina3132sfromlocalreceiverfunctionsimplicationsonregionaltectonics
_version_ 1807320633526190080

Ejemplares similares