A suture–related accretionary wedge formed in the Neoproterozoic Araçuaí orogen (SE Brazil) during Western Gondwanaland assembly

Peixoto, Eliza; Pedrosa-Soares, Antônio Carlos; Alkmim, Fernando Flecha de; Dussin, Ivo

doi:10.1016/j.gr.2013.11.010

Cited by 65 publications

(54 citation statements)

References 58 publications

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“…Tack et al 2001. Figure 11 shows a comparison of the detrital zircon age spectra of the two analysed samples and samples from the upper Macaúbas Group (upper Chapada Acauã Formation and Ribeirão da Folha Formation), which are considered to represent the distal passive margin of the precursor basin to the Araçuaí Orogen, and also a comparison with samples from the Nova Venécia Complex paragnaisses and the Rio Doce Group, which are believed to represent syn-orogenic basins related to the erosion of the G1 magmatic arc , 2011a, Gonçalves-Dias et al 2011, Novo 2013, Gradim et al 2014, Peixoto et al 2015, Kuchenbecker et al 2015.…”

Section: Sedimentary Provenancementioning

confidence: 99%

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Age, provenance and tectonic setting of the high-grade Jequitinhonha Complex, Araçuaí Orogen, eastern Brazil

et al. 2016

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ABSTRACT:The Jequitinhonha Complex of the northeastern Araçuaí orogen is an extensive sedimentary unit metamorphosed in the amphibolite-granulite facies transition around 580-545 Ma. The unit consists of Al-rich (kinzigitic) paragneisses with decametric intercalations of graphite gneisses and quartzites, and centimetric to metric lenses of calcsilicate rocks. A new detrital zircon U-Pb age spectrum is reported for a sample of quartzite, and whole-rock geochemical (major and trace elements, 9 samples) and Sm-Nd isotope data (10 samples) for Jequitinhonha Complex paragneiss. Together with published data these show that: (1) the geochemistry of paragneiss samples of the Jequitinhonha Complex are similar to those of passive margin sedimentary protoliths; (2) detrital zircon data yield U-Pb age populations between ca. 0.9 and 2.5 Ga; and (3) Sm-Nd T DM model ages range from 1.6 to 1.8 Ga and εNd (575 Ma) around -7.5. The data reveal a mixture of Cryogenian to Mesoproterozoic rift-related igneous rocks with the Palaeoproterozoic-Archaean basement rocks of the São Francisco-Congo palaeocontinent as the main source areas, and also support the correlation between the Jequitinhonha Complex and the passive margin units of the upper Macaúbas Group, constituting the precursor basin of the orogen. Our results, with the absence of ophiolites in the Jequitinhonha Complex, reinforce the interpretation that the São Francisco-Congo palaeocontinent was not divided to the north of the focused region, suggesting an ensialic termination of a gulf during the Neoproterozoic.

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Section: Sedimentary Provenancementioning

confidence: 99%

“…Shaded rows highlight more than 10% discordant data. Peixoto et al (2015); (6) PedrosaSoares et al (2000); (7) Kuchenbecker et al (2015).…”

Section: Sedimentary Provenancementioning

confidence: 99%

Age, provenance and tectonic setting of the high-grade Jequitinhonha Complex, Araçuaí Orogen, eastern Brazil

et al. 2016

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“…14.6c, d) with ocean-floor lithochemical signature occur closely associated with the Ribeirão da Folha Formation (Fig. 14.7) and represent tectonically dismembered ophiolite complexes (Pedrosa-Soares et al 1992, 2008Suita et al 2004;Queiroga 2010;Peixoto et al 2015). These complexes yielded Ediacaran magmatic crystallization U-Pb ages, suggesting oceanic spreading at least from ca.…”

Section: Ribeirão Da Folha Formationmentioning

confidence: 87%

“…14.6b-d), the Macaúbas rift evolved into a passive margin complex, recorded by a sedimentary pile deposited in a inland sea basin, almost completely surrounded by the São Francisco-Congo paleocontinent. The transition to the passive margin took place after the end of the Cryogenian glacial event, as recorded by the post-glacial Upper Chapada Acauã and Ribeirão da Folha formations (Pedrosa-Soares et al 2011a;Babinski et al 2012;Kuchenbecker et al 2015), which are the only units of the group containing Cryogenian detrital zircons (Peixoto et al 2015;Kuchenbecker et al 2015). The Jequitinhonha Complex, consisting of Al-rich paragneiss, quartzite, graphite gneiss and calc-silicate rocks exposed in the northern portion of the orogens' crystalline core, is currently viewed as correlative of the passive margin deposits of the Upper Macaúbas Group (Gonçalves-Dias et al 2011).…”

Section: Upper Macaúbas Groupmentioning

confidence: 99%

The Araçuaí Belt

Alkmim

Kuchenbecker

Reis

et al. 2016

São Francisco Craton, Eastern Brazil

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The Araçuaí belts extends along the curved southeastern margin of the São Francisco craton between the Brazilian coast and Lat 21°S, where it merges with the Ribeira belt. It represents the external, basement-involved fold-thrust belt of the Araçuaí-West Congo confined orogen (AWCO), which formed due to the closure of the terminal branch of the Adamastor ocean during the amalgamation of West Gondwana in the Ediacaran and beginning of the Cambrian. Bounded to the east and southeast by the high grade and granitic core of the AWCO, the Araçuaí belt involves a basement assemblage older than 1.8 Ga, the 1.7-0.9 Ga rift to rift-sag successions of the Espinhaço Supergroup, the Tonian-Edicaran rift-passive margin Macaúbas Group, as well as the syn-orogenic Salinas Formation and crustal derived granitic intrusions. The Macaúbas Group, the type unit of the belt, contains a glaciomarine sequence made up of thick diamictites, sandstones and Rapitan-type banded iron formations. The units exposed along the belt were metamorphosed under greenschist to amphibolite facies conditions and affected by thrusts, reverse faults and cratonward verging folds, developed between 575 and 530 Ma. The Araçuaí orogenic front propagates into the craton interior and interacts with preexistent rift structures. This chapter describes the stratigraphic framework and overall structure of the Araçuaí belt, emphasizing the paleogeographic and tectonic significance of its sedimentary and volcanic assemblages.

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“…The Upper Chapada Acauã Formation passes laterally into Ribeirão da Folha Formation, which contains distal passive-margin and ocean-floor deposits (Pedrosa-Soares et al 1992, 2011, Queiroga et al 2007. Detrital zircon grains suggest a maximum depositional age of around 806 Ma (Peixoto et al 2015). Metamafic and meta-ultramafic rocks with an ocean-floor lithochemical signature yielded Ediacaran magmatic crystallization U-Pb ages, which suggest oceanic spreading from at least ca.…”

Section: Central Espinhaço -Southern Portionmentioning

confidence: 99%

Tectonics and sedimentation of the central sector of the Santo Onofre rift, north Minas Gerais, Brazil

Costa

Filho

2017

Braz. J. Geol.

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ABSTRACT:The Santo Onofre Group registers the filling of a Tonian, intracontinental paleo-rift that developed along the northern and central Espinhaço regions. This paper examines this unit in the central Espinhaço region with stratigraphic analysis and U-Pb geochronology, reviewing and dividing into the Canatiba and Rio Peixe Bravo Formations, which include the Barrinha Member. The Canatiba Formation mainly comprises carbon-rich mudstones that were deposited through low-density turbidity flows that alternated with sediment settling under anoxic conditions. The Rio Peixe Bravo Formation consists of a succession of sandstones and minor mudstones, which were deposited through low-to high-density turbidity flows. The Barrinha Member mainly consists of conglomerates and is related to channelized debris flows. Detrital zircon grains show maximum depositional ages of 930 ± 33 Ma and around 865 Ma for the Canatiba and Rio Peixe Bravo Formations, respectively. We interpret the Santo Onofre rifting to be relative younger than that for the Sítio Novo Group and to be a precursor stage of the glacial and post-glacial rift-to-passive margin-related sequences of the Macaúbas Group. The lithostratigraphic term "Macaúbas Supergroup" would be of better use to accommodate the unconformity-bounded Tonian sequences that were related to the Rodinia breakup in the Congo-São Francisco paleocontinent. (Hoffman 1991, Meert 2001. Several phases that involved the breaking of Rodinia occurred, either through passive or active rifting, which were induced by remotely applied tensions (in-plane stress) and mantle plumes, respectively . These processes operated diachronically through a continental mass, and the full disintegration of the continent was complete at the end of the Tonian Period (Hoffman 1991, Cawood et al. 2016. Many rifts were formed before reaching this stage, some of which were aborted, and mafic dyke swarms intruded, which became dispersed in the scattered continents (Chew et al. 2010, Volkert et al. 2015. Investigations of these features have provided a better understanding of the space-temporal evolution of the Rodinia, for reconstructions (Hoffman 1991, Meert 2001. KEYWORDS:The Congo-São Francisco paleocontinent is characterized as one of several fragments of the Rodinia (Hoffman 1991. This paleocontinent encompasses the cover and basement rocks of São Francisco and Congo cratons and their marginal orogenic belts ( Fig. 1; Almeida 1977, Alkmim et al. 1993, Trompette 1994. The Espinhaço mountain range is a remarkable feature that extends with a sub-meridian direction across the entire extent of the Congo-São Francisco paleocontinent. The southern and central Espinhaço range regions integrate the Araçuaí fold and thrust belt as one of the external domains of the Neoproterozoic Araçuaí-West Congo orogen (Almeida 1977, Pedrosa-Soares et al. 1992, while the northern extension occurs along the eastern border of the Paramirim aulacogen, which was partially inverted, and involves the basement in the cover deformation (Schobbenhau...

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A suture–related accretionary wedge formed in the Neoproterozoic Araçuaí orogen (SE Brazil) during Western Gondwanaland assembly

Cited by 65 publications

References 58 publications

Age, provenance and tectonic setting of the high-grade Jequitinhonha Complex, Araçuaí Orogen, eastern Brazil

Age, provenance and tectonic setting of the high-grade Jequitinhonha Complex, Araçuaí Orogen, eastern Brazil

The Araçuaí Belt

Tectonics and sedimentation of the central sector of the Santo Onofre rift, north Minas Gerais, Brazil

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