Neoproterozoic magmatism and high-grade metamorphism in the Goiás Massif: New LA-MC-ICMPS U–Pb and Sm–Nd data and implications for collisional history of the Brasília Belt

ABSTRACT:The Brasília Belt is one of the most complete Neoproterozoic orogens in western Gondwana. Rapid progress on the understanding of the tectonic evolution of the belt was achieved due to new U-Pb data, combined with Sm-Nd and Lu-Hf analyses. The evolution of the Brasília orogen happened over a long period of time (900 -600 Ma) involving subduction, magmatism and terrain accretion, as a result of the consumption of the Goiás oceanic lithosphere. Provenance studies, based on U-Pb zircon data, indicate that the sedimentary rock units record different tectonic settings and stages of the evolution of the orogen. The Paranoá and Canastra groups represent passive margin sequences derived from the erosion of the São Francisco Craton. The Araxá and Ibiá groups, however, have dominant Neoproterozoic detrital zircon populations, as young as 650 Ma, suggesting derivation from the Goiás Magmatic Arc. The Goiás Magmatic Arc represents a composite arc terrain, formed by the accretion of older (ca. 0.9 -0.8 Ga) intraoceanic island arc(s), followed by more evolved continental arcs. It extends for several thousand kilometers, from SW Goiás, through NE Brazil and into Africa. Metamorphism took place between 650 -630 Ma reflecting final closure of the Goiás Ocean and continental collision. KEYWORDS: Brasília Belt; Neoproterozoic; U-Pb geochronology; Sediment provenance. RESUMO: A Faixa Brasília é um dos mais completos orógenos Neoproterozoicos no Gondwana Ocidental. Durante os últimos dez anos, o rápido progresso no entendimento da evolução tectônica desse orógeno foi proporcionado pela produção de novos dados geocronológicos U-Pb SHRIMP e LA-ICPMS, combinados com análises Sm-Nd e Lu-Hf. Os dados demonstraram que a evolução da Faixa Brasília acontenceu ao longo de um prolongado intervalo de tempo (900 -600 Ma), envolvendo subducção, atividade ígnea e acreção de terrenos, como resultado do consumo da litosfera do oceano Goiás. Estudos de proveniência de sedimentos baseados em geocronologia U-Pb de minerais detríticos indicam que as unidades sedimentares da Faixa

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“…690 and 651 Ma (Della Giustina et al 2009b). Therefore, magmatism and high grade metamorphism took place within this 40 My time span.…”

Section: Uruaçu Complexmentioning

confidence: 83%

The tectonic evolution of the Neoproterozoic Brasília Belt, central Brazil: a geochronological and isotopic approach

Pimentel

2016

Braz. J. Geol.

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115

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“…Ma e contemporâneo com idades interpretadas do pico metamórfico a formação de granulitos (Giustina et al, 2009ae Cordeiro et. al., 2014.…”

Section: Figura 32: Diagrama  Nd Versus Tdm Para As Rochas Intrusivaunclassified

Lineamento transbrasiliano, contribuição aerogeofísica, tectônica e geocronológica no setor nordeste da faixa Brasília

Praxedes¹

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___________________________________________________________________________ ii Ao meu Avô, Raimundo Praxedes (in memoriam)e Regina Célia Lima Silveira (in memoriam). Dissertação de Mestrado -Igor Fernandes Praxedes ___________________________________________________________________________ iii AGRADECIMENTOSA Deus, por ter me dado força ao longo destes 26 anos de muitas vitórias; à minha mãe Glades, por sempre estar ao meu lado nas minhas decisões, praticamente vivendo somente em prol da minha felicidade; à minha avó Nicélia, por ter sido essa minha segunda mãe maravilhosa; às minhas tias e tios que sempre foram exemplos em momentos importantes na minha vida; todos os familiares e amigos que de alguma forma participaram dessa trajetória, muito obrigado; À minha noiva Marcela, que sempre me apoiou nessa caminhada geológica, contribuindo muito nesta reta final de um capítulo da minha vida. Eu te amo. a pesquisa e ajudando a formar novos pesquisadores; A CAPES, pela concessão da bolsa de mestrado e ao Projeto Transbrasiliano (FUB/PETROBRAS) pelo apoio financeiro. Dissertação de Mestrado -Igor Fernandes Praxedes ___________________________________________________________________________ ivAgradeço também a empresa Brasil Minérios Ltda. por ter compreendido e contribuindo para minhas folgas em Brasília, indispensáveis para conclusão nos últimos meses.Muito obrigado a todos que de alguma forma colaboraram durante este caminho cheio de "pedras". (-8.43 to -0.12), showing that the rocks of the Goiás Massif are from crustal melting. Neoproterozoic rocks belonging to Santa Terezinha de Goiás Sequence (Goiás Magmatic Arc) were observed and proven dated hornblende-titanite metatonalito, obtaining crystallization age of 654.4 ± 4.2 Ma, with inherited zircon aged 672.6 ± 4.2 Ma. These rocks had metaigneous TDM ages between 1.09 and 0.88 Ga and εNd (t) positive (3.82 to 3.33), interpreted as representative of crustal accretion of juvenile material generated in the island arc environment in the Neoproterozoic. Tectonically, the study area consists of the LTB itself, formed by a large number of shear zones, typical of strike-slip system, reaching amphibolite facies, the main strike-slip shear zone NE Rio Formiga (ZCRF), establishing contact between Cavalcante-Arraias domain (DCA) and the Goiás Massif, and the strike-slip shear zone NE Jatobazeiro (ZCJ), limit of the Goiás Massif and the Goiás Magmatic Arc, both exhibiting foliation N30º-35ºE / 75º-86ºNW. Further east, the rock outcrops of the DCA, the main shear zones Cruz das Almas (ZCCA) and Mombuca (ZCM), both reaching green schist facies metamorphic. The ZCCA displays foliation NNE and dips moderately high for the WNW (N0º-40ºE / 60°-89ºNW), limiting the Almas-Conceição do Tocantins domain (DACT), the east and DCA, the west. The DACT presents few structures linked to Transbrasiliano Lineament. Lista de Figuras___________________________________________________________________________ viii

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“…Evidences from West Transaharan orogen in Africa and Central Brazil Fuck, 1992, Pimentel et al, 2000;Laux et al, 2005) DellaGiustina et al, 2009; (Neves, 2003;Neves et al 2009). …”

Section: Tectonic Implications: a Long-lived Continental Margin?mentioning

confidence: 99%

“…650 Ma (Baldwin and Brown, 2008;Della Giustina et al, 2009). Younger tectono-magmatic episodes have been registered until ca.…”

Section: Age Of the Amazonian-são Francisco-congo Collision Along Thementioning

confidence: 99%

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Evolução tectônica da margem ativa Neoproterozóica do Orógeno Gondwana Oeste na Província Borborema (NE-Brasil)

Araújo¹

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AgradecimentosAo orientador desta Tese, Prof. Umberto G. Cordani meus profundos agradecimentos por acreditar neste projeto, me orientar e me ensinar a como se portar cientificamente, pela liberdade, e por abrir TODAS as portas necessárias para a realização desta pesquisa. Ao Prof. Miguel A. S. Basei pelo companheirismo e orientação indispensável na zirconologia. Ao Prof. Roberto F. Weinberg pela orientação nos migmatitos e granitóides, por estar sempre aberto e solicito a uma boa discussão geológica e por ser um incentivador de novas ideias científicas. Aos Profs. Daniela Rubatto e Joerg Hermman por me ensinarem que a geocronologia não é somente a busca de uma idade. Ao Prof. Renaud Caby por compartilhar comigo todo seu conhecimento geológico do NE do Brasil e suas correlações africanas. Ao Prof. Yao Agboussomondé pela aventura na coleta ! iv! AbstractThe Neoproterozoic West Gondwana Orogen (WGO), suggested in this Thesis, is a linear belt that extended for more than 5000 km from nowadays northwest Africa to Central Brazil. Traditional views suggest that this orogen resulted from the consumption and closure of the Goiás-Pharusian Ocean that culminated in a continent-continent collision involving mainly the conjoined Amazon and West African cratons against the SãoFrancisco-Congo and Saharan cratons. In this Thesis it has been investigated the crustal evolution of an important sector of the WGO in NE-Brazil at the northwestern portion of the Borborema Province as well as in some areas of Africa in Togo and Mali using a coherent approach. U-Pb Zircon geochronology of siliciclastic and igneous rocks indicates a long-lived convergent tectonics (up to 400 m.y) related to the comsumption of the Goiás-Pharusian Ocean. In the studied, particularly in NE-Brazil in the Ceára Central Domain, convergentrelated magmatism can be divided into three main periods: i) an early period comprising essentially juvenile arc magmatism at ca. 880-800 Ma and continuing to 650 Ma as evidenced indirectly by detrital zircons from synorogenic deposits, ii) a more mature arc period at ca. 660-630 Ma characterized by hybrid mantle-crustal magmatic rocks, and iii) crustal anatexis at 625-618 Ma continuing until ca. 600 Ma. Protracted tectonic evolution in the WGO and synchronicity of UHP metamorphism in NE-Brazil, Togo and Mali indicate that continental subduction, and hence continental collision, occurred simultaneously over at least 2500 km during the Ediacaran period (620-610 Ma). Here, it has been proposed that Borborema Province development from 620 to 570 Ma resulted from two discrete collisional events. Collision I, along the WGO, took place at ca. 620-610 Ma as the result of collision between the Parnaíba Block, as the forefront of the much larger AmazonianWest Africa Craton, and the old basement of the Borborema Province. The suture zone related to this collision was reactivated by a dextral transform zone (the Transbrasiliano Lineament), allowing the Borborema Province to approach and collide against the São Francisco Craton in the s...

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Neoproterozoic magmatism and high-grade metamorphism in the Goiás Massif: New LA-MC-ICMPS U–Pb and Sm–Nd data and implications for collisional history of the Brasília Belt

Cited by 32 publications

References 35 publications

The tectonic evolution of the Neoproterozoic Brasília Belt, central Brazil: a geochronological and isotopic approach

The tectonic evolution of the Neoproterozoic Brasília Belt, central Brazil: a geochronological and isotopic approach

Lineamento transbrasiliano, contribuição aerogeofísica, tectônica e geocronológica no setor nordeste da faixa Brasília

Evolução tectônica da margem ativa Neoproterozóica do Orógeno Gondwana Oeste na Província Borborema (NE-Brasil)

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