Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina

Regional considerations on the tectonic regime during the emplacement of the Early Devonian magmatic units in the Sierra de San Luis are inferred from combined field, petrographic and AMS observations. Devonian granitoids of the Sierra de San Luis, in central Argentina, constitute elliptical composi...

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Autores principales: López de Luchi, M.G., Rapalini, A.E., Siegesmund, S., Steenken, A.
Formato: SER
Materias:
Devonian
emplacement
granitoid
magnetic fabric
tectonic evolution
Argentina
San Luis
Sierra de San Luis
South America
Western Hemisphere
World
Entovalva
Typha domingensis
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_03058719_v238_n_p447_LopezdeLuchi
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_03058719_v238_n_p447_LopezdeLuchi
record_format dspace
spelling todo:paper_03058719_v238_n_p447_LopezdeLuchi2023-10-03T15:21:59Z Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina López de Luchi, M.G. Rapalini, A.E. Siegesmund, S. Steenken, A. Devonian emplacement granitoid magnetic fabric tectonic evolution Argentina San Luis Sierra de San Luis South America Western Hemisphere World Entovalva Typha domingensis Regional considerations on the tectonic regime during the emplacement of the Early Devonian magmatic units in the Sierra de San Luis are inferred from combined field, petrographic and AMS observations. Devonian granitoids of the Sierra de San Luis, in central Argentina, constitute elliptical composite batholiths and make up the most voluminous magmatism that appears in the Sierra. Detailed fabric studies have been carried out on the La Totora batholith (33°09′ S, 65° 42′ W), which complement previous studies on two of the largest plutons in the Sierra de San Luis: The Renca and Las Chacras-Potrerillos batholiths. The studies comprised systematic field surveys, petrographic observations and anisotropy of magnetic susceptibility (AMS) measurements. Microstructural studies indicate that the batholith rocks are mainly characterized by magmatic microstructures with limited sub-magmatic to high-temperature solid-state deformation. All three batholiths possess concentric foliation patterns. The average magnetic foliation patterns in the studied plutons agree well with the macroscopic fabrics measured in the field indicating that the AMS-data can be used to study the orientation of fabric elements. Bulk susceptibility indicates a predominance of ferromagnetic contributions, although some paramagnetic sub-units are also present. Most foliations and lineations reflect magmatic flow and their attitude is linked to the interference between regional deformation and batholith inflation, i.e. fabrics may be due to regional strain in combination with the internal dynamics of the magma bodies. Rock fabrics are mainly described by oblate magnetic fabric ellipsoids. Magnetic lineations generally show a NNE-SSW trend that is interpreted to be controlled by the opening transtensional pull-apart structures during batholith inflation. It turns out that the Devonian batholiths intruded the basement syn-kinematically with respect to the Achalian deformational cycle. © The Geological Society of London 2004. SER info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03058719_v238_n_p447_LopezdeLuchi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Devonian
emplacement
granitoid
magnetic fabric
tectonic evolution
Argentina
San Luis
Sierra de San Luis
South America
Western Hemisphere
World
Entovalva
Typha domingensis
spellingShingle Devonian
emplacement
granitoid
magnetic fabric
tectonic evolution
Argentina
San Luis
Sierra de San Luis
South America
Western Hemisphere
World
Entovalva
Typha domingensis
López de Luchi, M.G.
Rapalini, A.E.
Siegesmund, S.
Steenken, A.
Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
topic_facet Devonian
emplacement
granitoid
magnetic fabric
tectonic evolution
Argentina
San Luis
Sierra de San Luis
South America
Western Hemisphere
World
Entovalva
Typha domingensis
description Regional considerations on the tectonic regime during the emplacement of the Early Devonian magmatic units in the Sierra de San Luis are inferred from combined field, petrographic and AMS observations. Devonian granitoids of the Sierra de San Luis, in central Argentina, constitute elliptical composite batholiths and make up the most voluminous magmatism that appears in the Sierra. Detailed fabric studies have been carried out on the La Totora batholith (33°09′ S, 65° 42′ W), which complement previous studies on two of the largest plutons in the Sierra de San Luis: The Renca and Las Chacras-Potrerillos batholiths. The studies comprised systematic field surveys, petrographic observations and anisotropy of magnetic susceptibility (AMS) measurements. Microstructural studies indicate that the batholith rocks are mainly characterized by magmatic microstructures with limited sub-magmatic to high-temperature solid-state deformation. All three batholiths possess concentric foliation patterns. The average magnetic foliation patterns in the studied plutons agree well with the macroscopic fabrics measured in the field indicating that the AMS-data can be used to study the orientation of fabric elements. Bulk susceptibility indicates a predominance of ferromagnetic contributions, although some paramagnetic sub-units are also present. Most foliations and lineations reflect magmatic flow and their attitude is linked to the interference between regional deformation and batholith inflation, i.e. fabrics may be due to regional strain in combination with the internal dynamics of the magma bodies. Rock fabrics are mainly described by oblate magnetic fabric ellipsoids. Magnetic lineations generally show a NNE-SSW trend that is interpreted to be controlled by the opening transtensional pull-apart structures during batholith inflation. It turns out that the Devonian batholiths intruded the basement syn-kinematically with respect to the Achalian deformational cycle. © The Geological Society of London 2004.
format SER
author López de Luchi, M.G.
Rapalini, A.E.
Siegesmund, S.
Steenken, A.
author_facet López de Luchi, M.G.
Rapalini, A.E.
Siegesmund, S.
Steenken, A.
author_sort López de Luchi, M.G.
title Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
title_short Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
title_full Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
title_fullStr Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
title_full_unstemmed Application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central Argentina
title_sort application of magnetic fabrics to the emplacement and tectonic history of devonian granitoids in central argentina
url http://hdl.handle.net/20.500.12110/paper_03058719_v238_n_p447_LopezdeLuchi
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AT siegesmunds applicationofmagneticfabricstotheemplacementandtectonichistoryofdevoniangranitoidsincentralargentina
AT steenkena applicationofmagneticfabricstotheemplacementandtectonichistoryofdevoniangranitoidsincentralargentina
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