Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil

Detalhes bibliográficos
Autor(a) principal: RIZZOTTO, Gilmar José
Data de Publicação: 2012
Outros Autores: HARTMANN, Léo Afraneo
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional de Geociências - RIGEO
Texto Completo: https://rigeo.cprm.gov.br/handle/doc/623
Resumo: We document the first-known Mesoproterozoic ophiolite from the southwestern part of the Amazon craton, corresponding to the Trincheira Complex of Calymmian age, and propose a tectonic model that explains many previously enigmatic features of the Precambrian history of this key craton, and discuss its role in the reconstruction of the Columbia supercontinent. The complex comprises extrusive rocks (fine-grained amphibolites derived from massive and pillowed basalts), mafic–ultramafic intrusive rocks, chert, banded iron formation (BIFs), pelites, psammitic and a smaller proportion of calc-silicate rocks. This sequence was deformed, metasomatized and metamorphosed during the development of the Alto Guaporé Belt, a Mesoproterozoic accretionary orogen. The rocks were deformed by a single tectonic event, which included isoclinal folding and metamorphism of the granulite–amphibolite facies. Layered magmatic structures were preserved in areas of low strain, including amygdaloidal and cumulate structures. Metamorphism was pervasive and reached temperatures of 780–853 °C in mafic granulites and 680–720 °C in amphibolites under an overall pressure of 6.8 kbar. The geochemical composition of the extrusive and intrusive rocks indicates that all noncumulus mafic–ultramafic rocks are tholeiitic basalts. The mafic–ultramafic rocks display moderate to strong fractionation of light rare earth elements (LREE), near-flat heavy rare earth element (HREE) patterns and moderate to strong negative high field strength element (HFSE) anomalies (especially Nb), a geochemical signature typical of subduction zones. The lowest units of mafic granulites and porphyroblastic amphibolites in the Trincheira ophiolite are similar to the modern mid-ocean ridge basalt (MORB), although they locally display small Ta, Ti and Nb negative anomalies, indicating a small subduction influence. This behavior changes to an island arc tholeiite (IAT) signature in the upper units of fine-grained amphibolites and amphibole rich-amphibolites, characterized by progressive depletion in the incompatible elements and more pronounced negative Ta and Nb anomalies, as well as common Ti|and Zr negative anomalies. Tectono-magmatic variation diagrams and chondrite-normalized REE and primitive mantle normalized patterns suggest a back-arc to intra-oceanic island arc tectonic regime for the eruption of these rocks. Therefore, the Trincheira ophiolite appears to have originated in an intraoceanic supra-subduction setting composed of an arc-back-arc system. Accordingly, the Trincheira Complex is a record of oceanic crust relics obducted during the collision of the Amazon craton and the Paraguá block during the Middle|Mesoproterozoic. Thus, the recognition of the Trincheira ophiolite and suture significantly changes views on the evolution of the southern margin of the Amazon craton, and how it can influence the global tectonics and the reconstruction of the continents
id CPRM_ba7d33f9960255d43b539967cfa59afa
oai_identifier_str oai:rigeo.sgb.gov.br:doc/623
network_acronym_str CPRM
network_name_str Repositório Institucional de Geociências - RIGEO
repository_id_str
spelling RIZZOTTO, Gilmar JoséHARTMANN, Léo Afraneo2013-12-19T16:32:49Z2013-12-19T16:32:49Z2012RIZZOTTO, Gilmar José; HARTMANN, Léo Afraneo. Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil. Lithos, Amsterdam, v.148, n.1, p.277–295, 2012.00244937https://rigeo.cprm.gov.br/handle/doc/623We document the first-known Mesoproterozoic ophiolite from the southwestern part of the Amazon craton, corresponding to the Trincheira Complex of Calymmian age, and propose a tectonic model that explains many previously enigmatic features of the Precambrian history of this key craton, and discuss its role in the reconstruction of the Columbia supercontinent. The complex comprises extrusive rocks (fine-grained amphibolites derived from massive and pillowed basalts), mafic–ultramafic intrusive rocks, chert, banded iron formation (BIFs), pelites, psammitic and a smaller proportion of calc-silicate rocks. This sequence was deformed, metasomatized and metamorphosed during the development of the Alto Guaporé Belt, a Mesoproterozoic accretionary orogen. The rocks were deformed by a single tectonic event, which included isoclinal folding and metamorphism of the granulite–amphibolite facies. Layered magmatic structures were preserved in areas of low strain, including amygdaloidal and cumulate structures. Metamorphism was pervasive and reached temperatures of 780–853 °C in mafic granulites and 680–720 °C in amphibolites under an overall pressure of 6.8 kbar. The geochemical composition of the extrusive and intrusive rocks indicates that all noncumulus mafic–ultramafic rocks are tholeiitic basalts. The mafic–ultramafic rocks display moderate to strong fractionation of light rare earth elements (LREE), near-flat heavy rare earth element (HREE) patterns and moderate to strong negative high field strength element (HFSE) anomalies (especially Nb), a geochemical signature typical of subduction zones. The lowest units of mafic granulites and porphyroblastic amphibolites in the Trincheira ophiolite are similar to the modern mid-ocean ridge basalt (MORB), although they locally display small Ta, Ti and Nb negative anomalies, indicating a small subduction influence. This behavior changes to an island arc tholeiite (IAT) signature in the upper units of fine-grained amphibolites and amphibole rich-amphibolites, characterized by progressive depletion in the incompatible elements and more pronounced negative Ta and Nb anomalies, as well as common Ti|and Zr negative anomalies. Tectono-magmatic variation diagrams and chondrite-normalized REE and primitive mantle normalized patterns suggest a back-arc to intra-oceanic island arc tectonic regime for the eruption of these rocks. Therefore, the Trincheira ophiolite appears to have originated in an intraoceanic supra-subduction setting composed of an arc-back-arc system. Accordingly, the Trincheira Complex is a record of oceanic crust relics obducted during the collision of the Amazon craton and the Paraguá block during the Middle|Mesoproterozoic. Thus, the recognition of the Trincheira ophiolite and suture significantly changes views on the evolution of the southern margin of the Amazon craton, and how it can influence the global tectonics and the reconstruction of the continentsElsevierGEOLOGIAGEOCRONOLOGIAGEOQUÍMICAMETAMORFISMOMESOPROTEROZOICOCRATON AMAZÔNICOBRASILGeological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazilinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleAmsterdamengreponame:Repositório Institucional de Geociências - RIGEOinstname:Companhia de Pesquisa de Recursos Minerais (CPRM)instacron:CPRMinfo:eu-repo/semantics/openAccessTEXTArt_Rizzotto_Rev_Cient.pdf.txtArt_Rizzotto_Rev_Cient.pdf.txtExtracted texttext/plain97942http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/2/Art_Rizzotto_Rev_Cient.pdf.txtdb49167fd75d76f73272a445812e736cMD52THUMBNAILArt_Rizzotto_Rev_Cient.pdf.jpgArt_Rizzotto_Rev_Cient.pdf.jpgGenerated Thumbnailimage/jpeg1464http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/3/Art_Rizzotto_Rev_Cient.pdf.jpg5c8701d2ffd68295c76be05209ca3ed2MD53ORIGINALArt_Rizzotto_Rev_Cient.pdfArt_Rizzotto_Rev_Cient.pdfproducao cientificaapplication/pdf4990466http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/1/Art_Rizzotto_Rev_Cient.pdfa19c25979b11fef1ee5207bc4c702b72MD51doc/6232023-02-13 11:13:20.21oai:rigeo.sgb.gov.br:doc/623Repositório InstitucionalONGhttps://rigeo.sgb.gov.br/oai/request https://rigeo.cprm.gov.br/oai/requestrigeo@sgb.gov.bropendoar:2023-02-13T14:13:20Repositório Institucional de Geociências - RIGEO - Companhia de Pesquisa de Recursos Minerais (CPRM)false
dc.title.none.fl_str_mv Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
title Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
spellingShingle Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
RIZZOTTO, Gilmar José
GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
METAMORFISMO
MESOPROTEROZOICO
CRATON AMAZÔNICO
BRASIL
title_short Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
title_full Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
title_fullStr Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
title_full_unstemmed Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
title_sort Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil
author RIZZOTTO, Gilmar José
author_facet RIZZOTTO, Gilmar José
HARTMANN, Léo Afraneo
author_role author
author2 HARTMANN, Léo Afraneo
author2_role author
dc.contributor.author.fl_str_mv RIZZOTTO, Gilmar José
HARTMANN, Léo Afraneo
dc.subject.por.fl_str_mv GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
METAMORFISMO
MESOPROTEROZOICO
CRATON AMAZÔNICO
BRASIL
topic GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
METAMORFISMO
MESOPROTEROZOICO
CRATON AMAZÔNICO
BRASIL
description We document the first-known Mesoproterozoic ophiolite from the southwestern part of the Amazon craton, corresponding to the Trincheira Complex of Calymmian age, and propose a tectonic model that explains many previously enigmatic features of the Precambrian history of this key craton, and discuss its role in the reconstruction of the Columbia supercontinent. The complex comprises extrusive rocks (fine-grained amphibolites derived from massive and pillowed basalts), mafic–ultramafic intrusive rocks, chert, banded iron formation (BIFs), pelites, psammitic and a smaller proportion of calc-silicate rocks. This sequence was deformed, metasomatized and metamorphosed during the development of the Alto Guaporé Belt, a Mesoproterozoic accretionary orogen. The rocks were deformed by a single tectonic event, which included isoclinal folding and metamorphism of the granulite–amphibolite facies. Layered magmatic structures were preserved in areas of low strain, including amygdaloidal and cumulate structures. Metamorphism was pervasive and reached temperatures of 780–853 °C in mafic granulites and 680–720 °C in amphibolites under an overall pressure of 6.8 kbar. The geochemical composition of the extrusive and intrusive rocks indicates that all noncumulus mafic–ultramafic rocks are tholeiitic basalts. The mafic–ultramafic rocks display moderate to strong fractionation of light rare earth elements (LREE), near-flat heavy rare earth element (HREE) patterns and moderate to strong negative high field strength element (HFSE) anomalies (especially Nb), a geochemical signature typical of subduction zones. The lowest units of mafic granulites and porphyroblastic amphibolites in the Trincheira ophiolite are similar to the modern mid-ocean ridge basalt (MORB), although they locally display small Ta, Ti and Nb negative anomalies, indicating a small subduction influence. This behavior changes to an island arc tholeiite (IAT) signature in the upper units of fine-grained amphibolites and amphibole rich-amphibolites, characterized by progressive depletion in the incompatible elements and more pronounced negative Ta and Nb anomalies, as well as common Ti|and Zr negative anomalies. Tectono-magmatic variation diagrams and chondrite-normalized REE and primitive mantle normalized patterns suggest a back-arc to intra-oceanic island arc tectonic regime for the eruption of these rocks. Therefore, the Trincheira ophiolite appears to have originated in an intraoceanic supra-subduction setting composed of an arc-back-arc system. Accordingly, the Trincheira Complex is a record of oceanic crust relics obducted during the collision of the Amazon craton and the Paraguá block during the Middle|Mesoproterozoic. Thus, the recognition of the Trincheira ophiolite and suture significantly changes views on the evolution of the southern margin of the Amazon craton, and how it can influence the global tectonics and the reconstruction of the continents
publishDate 2012
dc.date.issued.fl_str_mv 2012
dc.date.accessioned.fl_str_mv 2013-12-19T16:32:49Z
dc.date.available.fl_str_mv 2013-12-19T16:32:49Z
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.citation.fl_str_mv RIZZOTTO, Gilmar José; HARTMANN, Léo Afraneo. Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil. Lithos, Amsterdam, v.148, n.1, p.277–295, 2012.
dc.identifier.uri.fl_str_mv https://rigeo.cprm.gov.br/handle/doc/623
dc.identifier.issn.none.fl_str_mv 00244937
identifier_str_mv RIZZOTTO, Gilmar José; HARTMANN, Léo Afraneo. Geological and geochemical evolution of the Trincheira Complex, a Mesoproterozoic ophiolite in the southwestern Amazon craton, Brazil. Lithos, Amsterdam, v.148, n.1, p.277–295, 2012.
00244937
url https://rigeo.cprm.gov.br/handle/doc/623
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Repositório Institucional de Geociências - RIGEO
instname:Companhia de Pesquisa de Recursos Minerais (CPRM)
instacron:CPRM
instname_str Companhia de Pesquisa de Recursos Minerais (CPRM)
instacron_str CPRM
institution CPRM
reponame_str Repositório Institucional de Geociências - RIGEO
collection Repositório Institucional de Geociências - RIGEO
bitstream.url.fl_str_mv http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/2/Art_Rizzotto_Rev_Cient.pdf.txt
http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/3/Art_Rizzotto_Rev_Cient.pdf.jpg
http://rigeo.cprm.gov.br/jspui/bitstream/doc/623/1/Art_Rizzotto_Rev_Cient.pdf
bitstream.checksum.fl_str_mv db49167fd75d76f73272a445812e736c
5c8701d2ffd68295c76be05209ca3ed2
a19c25979b11fef1ee5207bc4c702b72
bitstream.checksumAlgorithm.fl_str_mv MD5
MD5
MD5
repository.name.fl_str_mv Repositório Institucional de Geociências - RIGEO - Companhia de Pesquisa de Recursos Minerais (CPRM)
repository.mail.fl_str_mv rigeo@sgb.gov.br
_version_ 1810104914951536640