Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira

Detalhes bibliográficos
Autor(a) principal: De Oliveira, Marcos Aurélio Farias [UNESP]
Data de Publicação: 2011
Outros Autores: De Melo, Rodrigo Prudente [UNESP], Nardy, Antônio José Ranalli [UNESP], Arab, Paola Bruno
Tipo de documento: Artigo
Idioma: por
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://rbg.sbgeo.org.br/index.php/rbg/article/view/17529/0
http://hdl.handle.net/11449/72647
Resumo: Metamafic orthoderivate rocks, characterized by MORB signatures and paleoproterozoic ages occur in Cajamar region central east part of São Paulo State, Brazil. They are associated to philites, metasandstones and metalimestones of São Roque Group volcanosedimentary sequence, Southeastern portion of the Ribeira Belt. For the metamafic rocks the assemblage of metamorphic peak is represented by actinolitealbite- epidote-chlorite typical of regional metamorphism, greenschist facies. For a good characterization of P and T parameters of metamorphism microprobe analyses of main minerals were performed. Metamorphism did not destroy completely the primary mineralogy of original basalt and microgabbro, and augite crystals are registered in many samples, preserved together with metamorphic assemblage, and possibly indicate that the igneous temperatures of crystallization are between 900 and 1.100°C. Textures of mineral equilibrium for the peak paragenesis are not always present in the studied samples. It may be partially caused by the superposition of retrometamorphic events that is a consequence of regional shearing process. Where the equilibrium is reached, chiefly in the occurrences in the south of the area temperature and pressure determinations indicate values close to 487 ± 42°C and 8,2 ± 2.0 kbar, respectively. Other values for P and T lower than that of the peak were also obtained in central and north portion of the area and they are: 450 ± 68°C for T e 4.7 kbar for P and 315 ± 26°C for T and 3.0 kbar for P and may indicate that the mineral equilibrium was not reached in these samples or that they represent the retrometamorphic event. As a concluding remark considering the metamorphic P-T path now obtained one can say that the exhumation process in this area occurred by isothermal decompression.
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spelling Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão RibeiraGeothermobarometric characterization of metabasic rocks of cajamar region (sp): São roque group, ribeira beltActinolite-albite-epidoto-chlorite assemblageGreenschist regional metamorphismMetamafic rocksRibeira BeltSão Roque GroupSoutheastern BrazilMetamafic orthoderivate rocks, characterized by MORB signatures and paleoproterozoic ages occur in Cajamar region central east part of São Paulo State, Brazil. They are associated to philites, metasandstones and metalimestones of São Roque Group volcanosedimentary sequence, Southeastern portion of the Ribeira Belt. For the metamafic rocks the assemblage of metamorphic peak is represented by actinolitealbite- epidote-chlorite typical of regional metamorphism, greenschist facies. For a good characterization of P and T parameters of metamorphism microprobe analyses of main minerals were performed. Metamorphism did not destroy completely the primary mineralogy of original basalt and microgabbro, and augite crystals are registered in many samples, preserved together with metamorphic assemblage, and possibly indicate that the igneous temperatures of crystallization are between 900 and 1.100°C. Textures of mineral equilibrium for the peak paragenesis are not always present in the studied samples. It may be partially caused by the superposition of retrometamorphic events that is a consequence of regional shearing process. Where the equilibrium is reached, chiefly in the occurrences in the south of the area temperature and pressure determinations indicate values close to 487 ± 42°C and 8,2 ± 2.0 kbar, respectively. Other values for P and T lower than that of the peak were also obtained in central and north portion of the area and they are: 450 ± 68°C for T e 4.7 kbar for P and 315 ± 26°C for T and 3.0 kbar for P and may indicate that the mineral equilibrium was not reached in these samples or that they represent the retrometamorphic event. As a concluding remark considering the metamorphic P-T path now obtained one can say that the exhumation process in this area occurred by isothermal decompression.Departamento de Petrologia e Metalogenia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Rio Claro (SP)Programa de Pós-Graduação em Geologia Regional IGCE UNESP, Rio Claro (SP)Programa de Pós-Graduação Escola de Engenharia de São Carlos, São Carlos (SP)Departamento de Petrologia e Metalogenia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Rio Claro (SP)Programa de Pós-Graduação em Geologia Regional IGCE UNESP, Rio Claro (SP)Universidade Estadual Paulista (Unesp)Escola de Engenharia de São CarlosDe Oliveira, Marcos Aurélio Farias [UNESP]De Melo, Rodrigo Prudente [UNESP]Nardy, Antônio José Ranalli [UNESP]Arab, Paola Bruno2014-05-27T11:25:59Z2014-05-27T11:25:59Z2011-09-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article375-389application/pdfhttp://rbg.sbgeo.org.br/index.php/rbg/article/view/17529/0Revista Brasileira de Geociencias, v. 41, n. 3, p. 375-389, 2011.0375-75362177-4382http://hdl.handle.net/11449/726472-s2.0-848634657692-s2.0-84863465769.pdfScopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPporRevista Brasileira de Geocienciasinfo:eu-repo/semantics/openAccess2023-11-02T06:09:18Zoai:repositorio.unesp.br:11449/72647Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T16:43:37.808047Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
Geothermobarometric characterization of metabasic rocks of cajamar region (sp): São roque group, ribeira belt
title Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
spellingShingle Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
De Oliveira, Marcos Aurélio Farias [UNESP]
Actinolite-albite-epidoto-chlorite assemblage
Greenschist regional metamorphism
Metamafic rocks
Ribeira Belt
São Roque Group
Southeastern Brazil
title_short Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
title_full Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
title_fullStr Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
title_full_unstemmed Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
title_sort Caracterização geotermobarométrica dos metabasitos de Cajamar (SP), Grupo São Roque, Cinturão Ribeira
author De Oliveira, Marcos Aurélio Farias [UNESP]
author_facet De Oliveira, Marcos Aurélio Farias [UNESP]
De Melo, Rodrigo Prudente [UNESP]
Nardy, Antônio José Ranalli [UNESP]
Arab, Paola Bruno
author_role author
author2 De Melo, Rodrigo Prudente [UNESP]
Nardy, Antônio José Ranalli [UNESP]
Arab, Paola Bruno
author2_role author
author
author
dc.contributor.none.fl_str_mv Universidade Estadual Paulista (Unesp)
Escola de Engenharia de São Carlos
dc.contributor.author.fl_str_mv De Oliveira, Marcos Aurélio Farias [UNESP]
De Melo, Rodrigo Prudente [UNESP]
Nardy, Antônio José Ranalli [UNESP]
Arab, Paola Bruno
dc.subject.por.fl_str_mv Actinolite-albite-epidoto-chlorite assemblage
Greenschist regional metamorphism
Metamafic rocks
Ribeira Belt
São Roque Group
Southeastern Brazil
topic Actinolite-albite-epidoto-chlorite assemblage
Greenschist regional metamorphism
Metamafic rocks
Ribeira Belt
São Roque Group
Southeastern Brazil
description Metamafic orthoderivate rocks, characterized by MORB signatures and paleoproterozoic ages occur in Cajamar region central east part of São Paulo State, Brazil. They are associated to philites, metasandstones and metalimestones of São Roque Group volcanosedimentary sequence, Southeastern portion of the Ribeira Belt. For the metamafic rocks the assemblage of metamorphic peak is represented by actinolitealbite- epidote-chlorite typical of regional metamorphism, greenschist facies. For a good characterization of P and T parameters of metamorphism microprobe analyses of main minerals were performed. Metamorphism did not destroy completely the primary mineralogy of original basalt and microgabbro, and augite crystals are registered in many samples, preserved together with metamorphic assemblage, and possibly indicate that the igneous temperatures of crystallization are between 900 and 1.100°C. Textures of mineral equilibrium for the peak paragenesis are not always present in the studied samples. It may be partially caused by the superposition of retrometamorphic events that is a consequence of regional shearing process. Where the equilibrium is reached, chiefly in the occurrences in the south of the area temperature and pressure determinations indicate values close to 487 ± 42°C and 8,2 ± 2.0 kbar, respectively. Other values for P and T lower than that of the peak were also obtained in central and north portion of the area and they are: 450 ± 68°C for T e 4.7 kbar for P and 315 ± 26°C for T and 3.0 kbar for P and may indicate that the mineral equilibrium was not reached in these samples or that they represent the retrometamorphic event. As a concluding remark considering the metamorphic P-T path now obtained one can say that the exhumation process in this area occurred by isothermal decompression.
publishDate 2011
dc.date.none.fl_str_mv 2011-09-01
2014-05-27T11:25:59Z
2014-05-27T11:25:59Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://rbg.sbgeo.org.br/index.php/rbg/article/view/17529/0
Revista Brasileira de Geociencias, v. 41, n. 3, p. 375-389, 2011.
0375-7536
2177-4382
http://hdl.handle.net/11449/72647
2-s2.0-84863465769
2-s2.0-84863465769.pdf
url http://rbg.sbgeo.org.br/index.php/rbg/article/view/17529/0
http://hdl.handle.net/11449/72647
identifier_str_mv Revista Brasileira de Geociencias, v. 41, n. 3, p. 375-389, 2011.
0375-7536
2177-4382
2-s2.0-84863465769
2-s2.0-84863465769.pdf
dc.language.iso.fl_str_mv por
language por
dc.relation.none.fl_str_mv Revista Brasileira de Geociencias
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 375-389
application/pdf
dc.source.none.fl_str_mv Scopus
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv
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