Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations

Detalhes bibliográficos
Autor(a) principal: FERREIRA FILHO, Cesar Fonseca
Data de Publicação: 2010
Outros Autores: PIMENTEL, Márcio Martins, ARAÚJO, Sylvia Maria de, LAUX, Jorge Henrique
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional de Geociências - RIGEO
Texto Completo: https://rigeo.cprm.gov.br/handle/doc/592
Resumo: A 350-km long belt of layered complexes and associated volcano-sedimentary sequences forms a continental-scale feature exposed along the internal portion of the Neoproterozoic Brasília Belt in central Brazil. This study provides new geochronological results and a critical review of the available data of these igneous associations of central Brazil. Precise age dating combined with geological and petrological studies indicate that this belt consists of two distinct igneous rock associations. The 1.25 and 0.79 Ga igneous episodes are constrained by reliable U–Pb zircon ages (SHRIMP and ID-TIMS)obtained in different regions and lithotypes of this belt. Both igneous associations were affected by high-grade metamorphism and tectonism at ca. 0.76 Ga, which partially disrupted the original igneous stratigraphy of the layered complexes and volcano-sedimentary sequences. The present configuration of this belt results from later|events, probably caused by final ocean closure and continental collision between the São Francisco and Amazonian continents at ca. 0.63 Ga. The 1.25 Ga magmatic event represents an igneous rock association comprising extensive bimodal volcanic rocks (Palmeirópolis, Juscelândia and Indaianópolis sequences) and associated large mafic layered intrusions (Serra dos Borges and Serra da Malacacheta complexes). Geochemical data of mafic volcanic rocks indicate compositions similar to MORB, suggesting a tectonic setting where continental rifting led to the opening of an ocean basin. Large layered intrusions coeval to the volcano-sedimentary sequence consist mainly of olivine plus plagioclase cumulates, with abundant troctolite and leucotroctolite, associated with olivine gabbro, gabbro, anorthosite and pyroxenite. These layered intrusions are characterized by moderately primitive olivine compositions (Fo 63–76), positive εNd(1250Ma) values, low contents of incompatible trace elements and LREE-depleted mantle-normalized-REE patterns. These features suggest an origin from the same depleted mantle source that produced the extensive MORB-type volcanism. Intrusion of layered complexes possibly occurred since the early stages of rifting, being emplaced both at the base of and within the volcanic pile. Different magmatic ages and fractionation trends of layered bodies suggest that they represent a cluster of intrusions that originated during the time span of the continental to oceanic ridge rifting event. The 0.79 Ga igneous association consists of three large layered intrusions (Niquelândia, Barro Alto, and Canabrava complexes). Despite intense tectonism, several striking geological similarities between the three separate bodies have been used to suggest that they originally constituted a single continuous magmatic structure. These layered intrusion are characterized by thick ultramafic zones, highly primitive compositions of olivine (up to Fo 93) and extensive Fe-enrichment trends of pyroxenes. Layered mafic–ultramafic rocks have abundant evidence of crustal contamination, including highly negative εNd(800Ma) values, as well as older crustal xenoliths and zircon xenocrysts. Cyclic units consisting of successive layers of dunite, harzburgite, orthopyroxenite, websterite and gabbronorite occur throughout the stratigraphy of these layered intrusions. The Niquelandia Complex ranks among the thickest layered intrusions in the world, and together with the Barro Alto and Canabrava layered intrusions represent an enormous volume of mantle-derived magma emplaced into the crust during a continental rifting event
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spelling FERREIRA FILHO, Cesar FonsecaPIMENTEL, Márcio MartinsARAÚJO, Sylvia Maria deLAUX, Jorge Henrique2013-12-19T16:32:45Z2013-12-19T16:32:45Z2010FERREIRA FILHO, Cesar Fonseca; PIMENTEL, Márcio Martins; ARAÚJO, Sylvia Maria de; LAUX, Jorge Henrique. Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations. Precambrian Research, Amsterdam, v.183, p.617–634, 2010.03019268https://rigeo.cprm.gov.br/handle/doc/592A 350-km long belt of layered complexes and associated volcano-sedimentary sequences forms a continental-scale feature exposed along the internal portion of the Neoproterozoic Brasília Belt in central Brazil. This study provides new geochronological results and a critical review of the available data of these igneous associations of central Brazil. Precise age dating combined with geological and petrological studies indicate that this belt consists of two distinct igneous rock associations. The 1.25 and 0.79 Ga igneous episodes are constrained by reliable U–Pb zircon ages (SHRIMP and ID-TIMS)obtained in different regions and lithotypes of this belt. Both igneous associations were affected by high-grade metamorphism and tectonism at ca. 0.76 Ga, which partially disrupted the original igneous stratigraphy of the layered complexes and volcano-sedimentary sequences. The present configuration of this belt results from later|events, probably caused by final ocean closure and continental collision between the São Francisco and Amazonian continents at ca. 0.63 Ga. The 1.25 Ga magmatic event represents an igneous rock association comprising extensive bimodal volcanic rocks (Palmeirópolis, Juscelândia and Indaianópolis sequences) and associated large mafic layered intrusions (Serra dos Borges and Serra da Malacacheta complexes). Geochemical data of mafic volcanic rocks indicate compositions similar to MORB, suggesting a tectonic setting where continental rifting led to the opening of an ocean basin. Large layered intrusions coeval to the volcano-sedimentary sequence consist mainly of olivine plus plagioclase cumulates, with abundant troctolite and leucotroctolite, associated with olivine gabbro, gabbro, anorthosite and pyroxenite. These layered intrusions are characterized by moderately primitive olivine compositions (Fo 63–76), positive εNd(1250Ma) values, low contents of incompatible trace elements and LREE-depleted mantle-normalized-REE patterns. These features suggest an origin from the same depleted mantle source that produced the extensive MORB-type volcanism. Intrusion of layered complexes possibly occurred since the early stages of rifting, being emplaced both at the base of and within the volcanic pile. Different magmatic ages and fractionation trends of layered bodies suggest that they represent a cluster of intrusions that originated during the time span of the continental to oceanic ridge rifting event. The 0.79 Ga igneous association consists of three large layered intrusions (Niquelândia, Barro Alto, and Canabrava complexes). Despite intense tectonism, several striking geological similarities between the three separate bodies have been used to suggest that they originally constituted a single continuous magmatic structure. These layered intrusion are characterized by thick ultramafic zones, highly primitive compositions of olivine (up to Fo 93) and extensive Fe-enrichment trends of pyroxenes. Layered mafic–ultramafic rocks have abundant evidence of crustal contamination, including highly negative εNd(800Ma) values, as well as older crustal xenoliths and zircon xenocrysts. Cyclic units consisting of successive layers of dunite, harzburgite, orthopyroxenite, websterite and gabbronorite occur throughout the stratigraphy of these layered intrusions. The Niquelandia Complex ranks among the thickest layered intrusions in the world, and together with the Barro Alto and Canabrava layered intrusions represent an enormous volume of mantle-derived magma emplaced into the crust during a continental rifting eventElsevierGEOLOGIAGEOCRONOLOGIAGEOQUÍMICAMAGMATISMOVULCANISMOPETROLOGIAZIRCON SHRIMPNEOPROTEROZOICOBRASILLayered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associationsinfo: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_laux.pdf.txtart_laux.pdf.txtExtracted texttext/plain78578http://rigeo.cprm.gov.br/jspui/bitstream/doc/592/2/art_laux.pdf.txt46d201c969bbdb38d7b28b6d48b8abe6MD52THUMBNAILart_laux.pdf.jpgart_laux.pdf.jpgGenerated Thumbnailimage/jpeg1638http://rigeo.cprm.gov.br/jspui/bitstream/doc/592/3/art_laux.pdf.jpge78cb5fff4689e95b88bd128a860072cMD53ORIGINALart_laux.pdfart_laux.pdfproducao cientificaapplication/pdf3968884http://rigeo.cprm.gov.br/jspui/bitstream/doc/592/1/art_laux.pdfa82cf081698fd333607f9238bd69b8faMD51doc/5922023-02-13 11:13:18.237oai:rigeo.sgb.gov.br:doc/592Repositório InstitucionalONGhttps://rigeo.sgb.gov.br/oai/request https://rigeo.cprm.gov.br/oai/requestrigeo@sgb.gov.bropendoar:2023-02-13T14:13:18Repositório Institucional de Geociências - RIGEO - Companhia de Pesquisa de Recursos Minerais (CPRM)false
dc.title.none.fl_str_mv Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
title Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
spellingShingle Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
FERREIRA FILHO, Cesar Fonseca
GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
MAGMATISMO
VULCANISMO
PETROLOGIA
ZIRCON SHRIMP
NEOPROTEROZOICO
BRASIL
title_short Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
title_full Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
title_fullStr Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
title_full_unstemmed Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
title_sort Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations
author FERREIRA FILHO, Cesar Fonseca
author_facet FERREIRA FILHO, Cesar Fonseca
PIMENTEL, Márcio Martins
ARAÚJO, Sylvia Maria de
LAUX, Jorge Henrique
author_role author
author2 PIMENTEL, Márcio Martins
ARAÚJO, Sylvia Maria de
LAUX, Jorge Henrique
author2_role author
author
author
dc.contributor.author.fl_str_mv FERREIRA FILHO, Cesar Fonseca
PIMENTEL, Márcio Martins
ARAÚJO, Sylvia Maria de
LAUX, Jorge Henrique
dc.subject.por.fl_str_mv GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
MAGMATISMO
VULCANISMO
PETROLOGIA
ZIRCON SHRIMP
NEOPROTEROZOICO
BRASIL
topic GEOLOGIA
GEOCRONOLOGIA
GEOQUÍMICA
MAGMATISMO
VULCANISMO
PETROLOGIA
ZIRCON SHRIMP
NEOPROTEROZOICO
BRASIL
description A 350-km long belt of layered complexes and associated volcano-sedimentary sequences forms a continental-scale feature exposed along the internal portion of the Neoproterozoic Brasília Belt in central Brazil. This study provides new geochronological results and a critical review of the available data of these igneous associations of central Brazil. Precise age dating combined with geological and petrological studies indicate that this belt consists of two distinct igneous rock associations. The 1.25 and 0.79 Ga igneous episodes are constrained by reliable U–Pb zircon ages (SHRIMP and ID-TIMS)obtained in different regions and lithotypes of this belt. Both igneous associations were affected by high-grade metamorphism and tectonism at ca. 0.76 Ga, which partially disrupted the original igneous stratigraphy of the layered complexes and volcano-sedimentary sequences. The present configuration of this belt results from later|events, probably caused by final ocean closure and continental collision between the São Francisco and Amazonian continents at ca. 0.63 Ga. The 1.25 Ga magmatic event represents an igneous rock association comprising extensive bimodal volcanic rocks (Palmeirópolis, Juscelândia and Indaianópolis sequences) and associated large mafic layered intrusions (Serra dos Borges and Serra da Malacacheta complexes). Geochemical data of mafic volcanic rocks indicate compositions similar to MORB, suggesting a tectonic setting where continental rifting led to the opening of an ocean basin. Large layered intrusions coeval to the volcano-sedimentary sequence consist mainly of olivine plus plagioclase cumulates, with abundant troctolite and leucotroctolite, associated with olivine gabbro, gabbro, anorthosite and pyroxenite. These layered intrusions are characterized by moderately primitive olivine compositions (Fo 63–76), positive εNd(1250Ma) values, low contents of incompatible trace elements and LREE-depleted mantle-normalized-REE patterns. These features suggest an origin from the same depleted mantle source that produced the extensive MORB-type volcanism. Intrusion of layered complexes possibly occurred since the early stages of rifting, being emplaced both at the base of and within the volcanic pile. Different magmatic ages and fractionation trends of layered bodies suggest that they represent a cluster of intrusions that originated during the time span of the continental to oceanic ridge rifting event. The 0.79 Ga igneous association consists of three large layered intrusions (Niquelândia, Barro Alto, and Canabrava complexes). Despite intense tectonism, several striking geological similarities between the three separate bodies have been used to suggest that they originally constituted a single continuous magmatic structure. These layered intrusion are characterized by thick ultramafic zones, highly primitive compositions of olivine (up to Fo 93) and extensive Fe-enrichment trends of pyroxenes. Layered mafic–ultramafic rocks have abundant evidence of crustal contamination, including highly negative εNd(800Ma) values, as well as older crustal xenoliths and zircon xenocrysts. Cyclic units consisting of successive layers of dunite, harzburgite, orthopyroxenite, websterite and gabbronorite occur throughout the stratigraphy of these layered intrusions. The Niquelandia Complex ranks among the thickest layered intrusions in the world, and together with the Barro Alto and Canabrava layered intrusions represent an enormous volume of mantle-derived magma emplaced into the crust during a continental rifting event
publishDate 2010
dc.date.issued.fl_str_mv 2010
dc.date.accessioned.fl_str_mv 2013-12-19T16:32:45Z
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dc.identifier.citation.fl_str_mv FERREIRA FILHO, Cesar Fonseca; PIMENTEL, Márcio Martins; ARAÚJO, Sylvia Maria de; LAUX, Jorge Henrique. Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations. Precambrian Research, Amsterdam, v.183, p.617–634, 2010.
dc.identifier.uri.fl_str_mv https://rigeo.cprm.gov.br/handle/doc/592
dc.identifier.issn.none.fl_str_mv 03019268
identifier_str_mv FERREIRA FILHO, Cesar Fonseca; PIMENTEL, Márcio Martins; ARAÚJO, Sylvia Maria de; LAUX, Jorge Henrique. Layered intrusions and volcanic sequences in Central Brazil: Geological and geochronological constraints for Mesoproterozoic (1.25 Ga) and Neoproterozoic (0.79 Ga) igneous associations. Precambrian Research, Amsterdam, v.183, p.617–634, 2010.
03019268
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