Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Geology |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892017000300427 |
Resumo: | ABSTRACT: In the Paleoproterozoic Transamazonas Province, synkinematic granitogenesis has taken place synchronously with compressive tectonic stress. The synkinematic character of the granites is marked by their WNW elongate shape, and by the presence of pervasive and concordant synmagmatic foliation. Ductile shear zones are concordant to the previous regional WNW structures, and tend to be accommodated along contacts between Rhyacian synkinematic granitoids and both Archean orthogneisses and Siderian metabasites. Locally phyllonitic shear zones and brittle-ductile shear zones with cataclasites are oriented subparallel to the preexisting ductile foliation. Late orogenic brittle faults N30E-trending strike-slip faults are either sinistral or destral. 40Ar/39Ar dating of muscovite developed on fault planes gave ages of 1977 ± 8 Ma and 1968 ± 11 Ma. Structural and geochronological data from rocks of the Transamazonas Province permit to conclude that most mylonites and brittle structures were controlled by preexisting structures such as geological contacts and petrographic facies boundaries. Compressive tectonic stress would have initiated at ca. 2100 Ma, since the former magmatic arc (Bacajaí complex), still present at 2070 Ma when syntectonic granites were emplaced and remained until 1975 Ma after granite plutonism and regional cooling. |
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Brazilian Journal of Geology |
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Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, BrazilSynkinematic granitesshear zonesstructural anisotropytectonic reactivationABSTRACT: In the Paleoproterozoic Transamazonas Province, synkinematic granitogenesis has taken place synchronously with compressive tectonic stress. The synkinematic character of the granites is marked by their WNW elongate shape, and by the presence of pervasive and concordant synmagmatic foliation. Ductile shear zones are concordant to the previous regional WNW structures, and tend to be accommodated along contacts between Rhyacian synkinematic granitoids and both Archean orthogneisses and Siderian metabasites. Locally phyllonitic shear zones and brittle-ductile shear zones with cataclasites are oriented subparallel to the preexisting ductile foliation. Late orogenic brittle faults N30E-trending strike-slip faults are either sinistral or destral. 40Ar/39Ar dating of muscovite developed on fault planes gave ages of 1977 ± 8 Ma and 1968 ± 11 Ma. Structural and geochronological data from rocks of the Transamazonas Province permit to conclude that most mylonites and brittle structures were controlled by preexisting structures such as geological contacts and petrographic facies boundaries. Compressive tectonic stress would have initiated at ca. 2100 Ma, since the former magmatic arc (Bacajaí complex), still present at 2070 Ma when syntectonic granites were emplaced and remained until 1975 Ma after granite plutonism and regional cooling.Sociedade Brasileira de Geologia2017-09-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892017000300427Brazilian Journal of Geology v.47 n.3 2017reponame:Brazilian Journal of Geologyinstname:Sociedade Brasileira de Geologia (SBGEO)instacron:SBGEO10.1590/2317-4889201720170033info:eu-repo/semantics/openAccessPerico,EdimarBarros,Carlos Eduardo de MesquitaMancini,FernandoRostirolla,Sidnei Pireseng2017-11-13T00:00:00Zoai:scielo:S2317-48892017000300427Revistahttp://bjg.siteoficial.ws/index.htmhttps://old.scielo.br/oai/scielo-oai.phpsbgsede@sbgeo.org.br||claudio.riccomini@gmail.com2317-46922317-4692opendoar:2017-11-13T00:00Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO)false |
dc.title.none.fl_str_mv |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
title |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
spellingShingle |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil Perico,Edimar Synkinematic granites shear zones structural anisotropy tectonic reactivation |
title_short |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
title_full |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
title_fullStr |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
title_full_unstemmed |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
title_sort |
Protracted deformation during cooling of the Paleoproterozoic arc system as constrained by 40Ar/39Ar ages of muscovite from brittle faults: the Transamazonan Bacajá Terrane, Brazil |
author |
Perico,Edimar |
author_facet |
Perico,Edimar Barros,Carlos Eduardo de Mesquita Mancini,Fernando Rostirolla,Sidnei Pires |
author_role |
author |
author2 |
Barros,Carlos Eduardo de Mesquita Mancini,Fernando Rostirolla,Sidnei Pires |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Perico,Edimar Barros,Carlos Eduardo de Mesquita Mancini,Fernando Rostirolla,Sidnei Pires |
dc.subject.por.fl_str_mv |
Synkinematic granites shear zones structural anisotropy tectonic reactivation |
topic |
Synkinematic granites shear zones structural anisotropy tectonic reactivation |
description |
ABSTRACT: In the Paleoproterozoic Transamazonas Province, synkinematic granitogenesis has taken place synchronously with compressive tectonic stress. The synkinematic character of the granites is marked by their WNW elongate shape, and by the presence of pervasive and concordant synmagmatic foliation. Ductile shear zones are concordant to the previous regional WNW structures, and tend to be accommodated along contacts between Rhyacian synkinematic granitoids and both Archean orthogneisses and Siderian metabasites. Locally phyllonitic shear zones and brittle-ductile shear zones with cataclasites are oriented subparallel to the preexisting ductile foliation. Late orogenic brittle faults N30E-trending strike-slip faults are either sinistral or destral. 40Ar/39Ar dating of muscovite developed on fault planes gave ages of 1977 ± 8 Ma and 1968 ± 11 Ma. Structural and geochronological data from rocks of the Transamazonas Province permit to conclude that most mylonites and brittle structures were controlled by preexisting structures such as geological contacts and petrographic facies boundaries. Compressive tectonic stress would have initiated at ca. 2100 Ma, since the former magmatic arc (Bacajaí complex), still present at 2070 Ma when syntectonic granites were emplaced and remained until 1975 Ma after granite plutonism and regional cooling. |
publishDate |
2017 |
dc.date.none.fl_str_mv |
2017-09-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892017000300427 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892017000300427 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/2317-4889201720170033 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
dc.source.none.fl_str_mv |
Brazilian Journal of Geology v.47 n.3 2017 reponame:Brazilian Journal of Geology instname:Sociedade Brasileira de Geologia (SBGEO) instacron:SBGEO |
instname_str |
Sociedade Brasileira de Geologia (SBGEO) |
instacron_str |
SBGEO |
institution |
SBGEO |
reponame_str |
Brazilian Journal of Geology |
collection |
Brazilian Journal of Geology |
repository.name.fl_str_mv |
Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO) |
repository.mail.fl_str_mv |
sbgsede@sbgeo.org.br||claudio.riccomini@gmail.com |
_version_ |
1752122398542397440 |