Orosirian (ca. 1.96 Ga) mafic crust of the northwestern São Francisco Craton margin: Petrography, geochemistry and geochronology of amphibolites from the Rio Preto fold belt basement, NE Brazil

Caxito, Fabrício de Andrade; Uhlein, Alexandre; Dantas, Elton Luiz; Stevenson, Ross; Pedrosa-Soares, Antônio Carlos

doi:10.1016/j.jsames.2015.02.003

Cited by 28 publications

(9 citation statements)

References 64 publications

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“…Although Rhyacian rocks are common and widespread in the Atlantic shield (in effect composing the majority of it), Orosirian rocks, on the other hand, are quite scarce, and might represent a magmatic event that was not previously considered in its full importance until recent times. In effect, in the southern Borborema Province, in the basement of the Rio Preto Fold belt, Caxito et al (2015) recognized the first well described Orosirian rocks of the region, amphibolites which were then interpreted as developed in a supra-subduction zone setting, much like our interpretation for the Sumé Complex. The recognition of Orosirian fragments in both the southern and central Borborema Province might provide clues to a previously undetected important tectonic scenario, which deserves further studies and investigation.…”

Section: Stratigraphic Implications and Regional Correlationssupporting

confidence: 62%

Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil

Santos¹,

Santos

2019

Braz. J. Geol.

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The Alto Moxotó Terrane represents the largest exposure of Paleoproterozoic rocks in the central Borborema Province. Several medium-to high-grade metamorphic units are described in the terrane, however geochronological data are still scarce, and the main periods of crust buildup and recycling are poorly known. In this study, we investigate the nature and age of metagranitic and metamafic-ultramafic rocks in the type area of the Sumé Complex. U-Pb zircon data from a metasyenogranite yields a concordant age of 1.97 Ga, which is in contrast with the previously published age of the complex (c. 640 Ma). In addition, Sm-Nd isotope signature indicates Paleoproterozoic to Mesoarchean sources that coupled with negative εNd(t) values suggest reworking of a preexisting crust. Whole-rock geochemical data indicate that metamafic rocks are similar to those already described in the terrane, corresponding to island-arc tholeiites, whereas the metagranitic rocks share similarities with magmas that were generated in an evolved stage of an orogenic setting. The obtained results are coherent with a long-lived Paleoproterozoic accretionary-collisional event (c. 2.1-1.9 Ga) described in the Borborema Province, which is correlative with Paleoproterozoic (c. 2.2-2.0 Ga) basement inliers/terranes from Pan-African Fold belts..

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Section: Stratigraphic Implications and Regional Correlationssupporting

confidence: 62%

Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil

Santos¹,

Santos

2019

Braz. J. Geol.

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“…The Sm and Nd concentrations and the 147 Sm / 144 Nd ratios have an reproducibility of 0.5% that corresponds to an average error on the initial εNd value of ± 0.5. For details on the methodology used in the geochemical and Sm-Nd analysis, see Caxito et al (2015).…”

Section: Methodsmentioning

confidence: 99%

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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“…3.75-2.7 Ga;Dantas et al 2013, Ganade de Araújo et al 2017, Santos et al 2017a and Paleoproterozoic blocks/terranes (ca. 2.2-2.0 Ga; Hollanda et al 2011, Caxito et al 2015, Santos L.C.M.L. et al 2013, 2015 mostly bounded by Neoproterozoic metavolcanosedimentary domains generated during the Cariris Velhos (ca.…”

Section: Geological Settingmentioning

confidence: 99%

Accretionary models for the Neoproterozoic evolution of the Borborema Province: advances and open questions

Santos

Caxito

2021

Braz. J. Geol.

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The current knowledge on the accretionary evolution of the Borborema Province is evaluated considering recently published data and interpretations. Early to late Neoproterozoic eclogite, ophiolite, and magmatic arc remnants have been documented and point to oceanic crust consumption. Isotopic contrasts as well as geophysical anomalies across the major domain boundaries are suggestive of collisional sutures and a speculative model of terrane accretion is presented here. On the other hand, the lack of concise evidence for some of the proposed deep-seated structures as well as putative lithospheric continuity in both sides of it suggest reworking of previously continuous lithosphere through intracontinental deformation in localized sectors of the province interior. It is patent that one model does not preclude the other and available evidence so far has triggered the emergence of conciliatory proposals for the Neoporterozoic history the Borborema Province.

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Orosirian (ca. 1.96 Ga) mafic crust of the northwestern São Francisco Craton margin: Petrography, geochemistry and geochronology of amphibolites from the Rio Preto fold belt basement, NE Brazil

Cited by 28 publications

References 64 publications

Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil

Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil

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

Accretionary models for the Neoproterozoic evolution of the Borborema Province: advances and open questions

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