The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview

The Eastern Sierras Pampeanas were structured by three main events: the Ediacaran to early Cambrian (580-510 Ma) Pampean, the late Cambrian-Ordovician (500-440 Ma) Famatinian and the Devonian-Carboniferous (400-350 Ma) Achalian orogenies. Geochronological and Sm-Nd isotopic evidence combined with pe...

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Detalles Bibliográficos
Publicado: 2011
Materias:
Eastern Sierras Pampeanas
Magmatism-metamorphism
Neoproterozoic-early Paleozoic orogenies
Sm-Nd systematics
Tectonic evolution
active margin
age determination
continental crust
crustal structure
Devonian
geochronology
isotopic analysis
magmatism
metamorphic rock
metamorphism
Ordovician
Paleozoic
Proterozoic
samarium-neodymium dating
tectonic evolution
Argentina
Sierras Pampeanas
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14373254_v100_n2_p465_Steenken
http://hdl.handle.net/20.500.12110/paper_14373254_v100_n2_p465_Steenken
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_14373254_v100_n2_p465_Steenken
record_format dspace
spelling paper:paper_14373254_v100_n2_p465_Steenken2023-06-08T16:15:43Z The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview Eastern Sierras Pampeanas Magmatism-metamorphism Neoproterozoic-early Paleozoic orogenies Sm-Nd systematics Tectonic evolution active margin age determination continental crust crustal structure Devonian geochronology isotopic analysis magmatism metamorphic rock metamorphism Ordovician Paleozoic Proterozoic samarium-neodymium dating tectonic evolution Argentina Sierras Pampeanas The Eastern Sierras Pampeanas were structured by three main events: the Ediacaran to early Cambrian (580-510 Ma) Pampean, the late Cambrian-Ordovician (500-440 Ma) Famatinian and the Devonian-Carboniferous (400-350 Ma) Achalian orogenies. Geochronological and Sm-Nd isotopic evidence combined with petrological and structural features allow to speculate for a major rift event (Ediacaran) dividing into two Mesoproterozoic major crustal blocks (source of the Grenvillian age peaks in the metaclastic rocks). This event would be coeval with the development of arc magmatism along the eastern margin of the eastern block. Closure of this eastern margin led to a Cambrian active margin (Sierra Norte arc) along the western margin of the eastern block in which magmatism reworked the same crustal block. Consumption of a ridge segment (input of OIB signature mafic magmas) which controlled granulite-facies metamorphism led to a final collision (Pampean orogeny) with the western Mesoprotrozoic block. Sm-Nd results for the metamorphic basement suggest that the TDM age interval of 1.8-1.7 Ga, which is associated with the less radiogenic values of εNd(540) (-6 to -8), can be considered as the mean average crustal composition for the Eastern Sierras Pampeanas. Increasing metamorphic grade in rocks with similar detrital sources and metamorphic ages like in the Sierras de Córdoba is associated with a younger TDM age and a more positive εNd(540) value. Pampean pre-540 Ma granitoids form two clusters, one with TDM ages between 2.0 and 1.75 Ga and another between 1.6 and 1.5 Ga. Pampean post-540 Ma granitoids exhibit more homogenous TDM ages ranging from 2.0 to 1.75 Ga. Ordovician re-activation of active margin along the western part of the block that collided in the Cambrian led to arc magmatism (Famatinian orogeny) and related ensialic back-arc basin in which high-grade metamorphism is related to mid-crustal felsic plutonism and mafic magmatism with significant contamination of continental crust. TDM values for the Ordovician Famatinian granitoids define a main interval of 1.8-1.6, except for the Ordovician TTG suites of the Sierras de Córdoba, which show younger TDM ages ranging from 1.3 to 1.0 Ga. In Devonian times (Achalian orogeny), a new subduction regime installed west of the Eastern Sierras Pampeanas. Devonian magmatism in the Sierras exhibit process of mixing/assimilation of depleted mantle signature melts and continental crust. Achalian magmatism exhibits more radiogenic εNd(540) values that range between 0.5 and -4 and TDM ages younger than 1.3 Ga. In pre-Devonian times, crustal reworking is dominant, whereas processes during Devonian times involved different geochemical and isotopic signatures that reflect a major input of juvenile magmatism. © 2010 Springer-Verlag. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14373254_v100_n2_p465_Steenken http://hdl.handle.net/20.500.12110/paper_14373254_v100_n2_p465_Steenken
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Eastern Sierras Pampeanas
Magmatism-metamorphism
Neoproterozoic-early Paleozoic orogenies
Sm-Nd systematics
Tectonic evolution
active margin
age determination
continental crust
crustal structure
Devonian
geochronology
isotopic analysis
magmatism
metamorphic rock
metamorphism
Ordovician
Paleozoic
Proterozoic
samarium-neodymium dating
tectonic evolution
Argentina
Sierras Pampeanas
spellingShingle Eastern Sierras Pampeanas
Magmatism-metamorphism
Neoproterozoic-early Paleozoic orogenies
Sm-Nd systematics
Tectonic evolution
active margin
age determination
continental crust
crustal structure
Devonian
geochronology
isotopic analysis
magmatism
metamorphic rock
metamorphism
Ordovician
Paleozoic
Proterozoic
samarium-neodymium dating
tectonic evolution
Argentina
Sierras Pampeanas
The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
topic_facet Eastern Sierras Pampeanas
Magmatism-metamorphism
Neoproterozoic-early Paleozoic orogenies
Sm-Nd systematics
Tectonic evolution
active margin
age determination
continental crust
crustal structure
Devonian
geochronology
isotopic analysis
magmatism
metamorphic rock
metamorphism
Ordovician
Paleozoic
Proterozoic
samarium-neodymium dating
tectonic evolution
Argentina
Sierras Pampeanas
description The Eastern Sierras Pampeanas were structured by three main events: the Ediacaran to early Cambrian (580-510 Ma) Pampean, the late Cambrian-Ordovician (500-440 Ma) Famatinian and the Devonian-Carboniferous (400-350 Ma) Achalian orogenies. Geochronological and Sm-Nd isotopic evidence combined with petrological and structural features allow to speculate for a major rift event (Ediacaran) dividing into two Mesoproterozoic major crustal blocks (source of the Grenvillian age peaks in the metaclastic rocks). This event would be coeval with the development of arc magmatism along the eastern margin of the eastern block. Closure of this eastern margin led to a Cambrian active margin (Sierra Norte arc) along the western margin of the eastern block in which magmatism reworked the same crustal block. Consumption of a ridge segment (input of OIB signature mafic magmas) which controlled granulite-facies metamorphism led to a final collision (Pampean orogeny) with the western Mesoprotrozoic block. Sm-Nd results for the metamorphic basement suggest that the TDM age interval of 1.8-1.7 Ga, which is associated with the less radiogenic values of εNd(540) (-6 to -8), can be considered as the mean average crustal composition for the Eastern Sierras Pampeanas. Increasing metamorphic grade in rocks with similar detrital sources and metamorphic ages like in the Sierras de Córdoba is associated with a younger TDM age and a more positive εNd(540) value. Pampean pre-540 Ma granitoids form two clusters, one with TDM ages between 2.0 and 1.75 Ga and another between 1.6 and 1.5 Ga. Pampean post-540 Ma granitoids exhibit more homogenous TDM ages ranging from 2.0 to 1.75 Ga. Ordovician re-activation of active margin along the western part of the block that collided in the Cambrian led to arc magmatism (Famatinian orogeny) and related ensialic back-arc basin in which high-grade metamorphism is related to mid-crustal felsic plutonism and mafic magmatism with significant contamination of continental crust. TDM values for the Ordovician Famatinian granitoids define a main interval of 1.8-1.6, except for the Ordovician TTG suites of the Sierras de Córdoba, which show younger TDM ages ranging from 1.3 to 1.0 Ga. In Devonian times (Achalian orogeny), a new subduction regime installed west of the Eastern Sierras Pampeanas. Devonian magmatism in the Sierras exhibit process of mixing/assimilation of depleted mantle signature melts and continental crust. Achalian magmatism exhibits more radiogenic εNd(540) values that range between 0.5 and -4 and TDM ages younger than 1.3 Ga. In pre-Devonian times, crustal reworking is dominant, whereas processes during Devonian times involved different geochemical and isotopic signatures that reflect a major input of juvenile magmatism. © 2010 Springer-Verlag.
title The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
title_short The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
title_full The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
title_fullStr The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
title_full_unstemmed The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: An overview
title_sort neoproterozoic-early paleozoic metamorphic and magmatic evolution of the eastern sierras pampeanas: an overview
publishDate 2011
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14373254_v100_n2_p465_Steenken
http://hdl.handle.net/20.500.12110/paper_14373254_v100_n2_p465_Steenken
_version_ 1768544655356461056

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