Petrographical and geochemical signatures of the Granja paragneisses (Médio Coreaú Domain, NW Ceará, Brasil)

Silva, A. J.F.; Azevedo, M.R.; Aguado, B. Valle; Neto, José de Araújo Nogueira; Santos, Ticiano José Saraiva dos; Silva, F. D.O.

doi:10.3989/egeol.41750.326

Cited by 3 publications

(3 citation statements)

References 26 publications

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“…The record of Rhyacian‐Orosirian orogenic events in the Ceará Central Domain demonstrates that the Palaeoproterozoic basement of the Northern Borborema Province is directly related to the Atlantica palaeocontinent amalgamation from 2.1 to 1.8 Ga (Meert & Santosh, 2017; Rogers & Santosh, 2002, 2009; Zhao, Cawood, Wilde, & Sun, 2002; Zhao, Li, Sun, & Wilde, 2011; Zhao, Sun, Wilde, & Li, 2004). In the Borborema Province, Rhyacian‐Orosirian khondalitic rocks also occur in the Jaguaretama Complex (Calado et al, 2019) and in the Granja Complex (Santos et al, 2001; Silva et al, 2014). The rocks from the Ceará Khondalite Belt and the Jaguaretama Complex (see JC in Figure 1b) are limited by the transcurrent Senador Pompeu Shear Zone generated in the Neoproterozoic.…”

Section: Discussionmentioning

confidence: 99%

“…In the Borborema Province, Rhyacian-Orosirian khondalitic rocks also occur in the Jaguaretama Complex (Calado et al, 2019) and in the Granja Complex (Santos et al, 2001;Silva et al, 2014). The rocks from the Ceará Khondalite Belt and the Jaguaretama Complex (see JC in metamorphic events linked to the building of metamorphic belts that are essential for palaeogeographic reconstructions (e.g., Chaves, 2021).…”

Section: Melting Of Metasedimentary Rocks and Orthogneisses Of The Sãomentioning

confidence: 99%

“…In the Brasília Belt, the Ticunzal Fomation was deposited in a continental arc‐related basin between 2.16 and 2.19 Ga (Cuadros et al, 2017). The Palaeoproterozoic khondalitic rocks of the Northern Borborema Province (Figure 1b) occur in the Granja (Santos, Nogueira Neto, Fetter, & Hackspacher, 2001; Silva et al, 2014), Jaguaretama (Calado et al, 2019), and Canindé do Ceará (Fragomeni & Pereira, 2013) complexes. The latter—object of this study—is flanked by greenstone belts and Palaeoproterozoic intraoceanic and continental magmatic arcs (Costa et al, 2018; Costa, Palheta, Rodrigues, Gomes, & Vasconcelos, 2015; Martins, Oliveira, & Lafon, 2009) and metasedimentary and ortho‐derived rocks associated with a Neoproterozoic continental magmatic arc (Figure 1c) (Fetter et al, 2003; Ganade et al, 2014; Pitombeira, Amaral, Santos, Dantas, & Fuck, 2021; Torres et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Rhyacian‐Orosirian Khondalite Belt in the Borborema Province (NE Brazil): An active margin setting based on U–Pb zircon and monazite constraints

Muniz¹,

Santos²,

Dantas

et al. 2022

Geological Journal

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Khondalite belts are of special importance is delimiting old suture zones and in palaeocontinental reconstruction of Precambrian terrains. In the South‐American Platform, khondalitic rocks surround cratonic areas and Archean blocks reworked in the Neoproterozoic, an example of which being the Ceará Khondalite Belt (CKB). Located in the northern portion of the Borborema Province in NE Brazil, CKB is here described by means of its petrographic, structural, and LA‐SF‐ICP‐MS zircon and monazite U–Pb geochronological characteristics. CKB constitutes an E‐W to NE–SW striking belt comprising migmatitic spinel (hercynite)‐ and graphite‐bearing cordierite‐garnet‐sillimanite‐biotite gneisses, small granulitic boudins, garnet‐biotite quartzite, lenses of garnet amphibolite, calc‐silicate rock, gondite, and mylonitized leucogneiss. Relicts of Palaeoproterozoic island and continental arcs surrounding CKB are represented by tonalitic and dioritic gneiss, respectively. The contact between CKB and the Neoproterozoic Independência Unit is marked by a transpressional shear zone to the north, whereas the contact between CKB and Archean and Palaeoproterozoic rocks to the south is via a N‐verging thrust fault. The metamorphic peak is given by the parageneses: spinel (hercynite)‐quartz, spinel (hercynite)‐cordierite, and cordierite‐sillimanite‐garnet, possibly stable under UHT conditions. Crystallization ages of 2,086 ± 8 Ma and 2,063 ± 9 Ma were obtained by dating CKB migmatitic dioritic orthogneisses using the zircon U–Pb method. The CKB para‐derived rocks yielded detrital zircon U–Pb age peaks at 2,190, 2,130, and 2,060 Ma. Three metamorphic stages are identified in the Palaeoproterozoic via U–Pb dating of zircon rims and monazite at 2,094 ± 4 Ma, 2,055 ± 5 Ma, and 1,958 ± 3 Ma. A fourth metamorphic event with associated migmatization in shear zones took place in the Neoproterozoic between 595 ± 6 Ma and 573 ± 15 Ma, as indicated by dating zircon rims and monazite, respectively. Our study shows that the metamorphic events occurring in CKB in the Palaeoproterozoic share similarities with those that affected the khondalitic rocks bordering the São Francisco and the North China cratons, which suggests the existence of a continuous orogen during the Rhyacian‐Orosirian related to the Columbia Supercontinent amalgamation.

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Section: Discussionmentioning

confidence: 99%

Section: Melting Of Metasedimentary Rocks and Orthogneisses Of The Sãomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rhyacian‐Orosirian Khondalite Belt in the Borborema Province (NE Brazil): An active margin setting based on U–Pb zircon and monazite constraints

Muniz¹,

Santos²,

Dantas

et al. 2022

Geological Journal

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The Ediacaran metamorphosed banded iron formation (BIF) at Gohar Zamin mine (Gol-e-Gohar #3 anomaly), Sirjan (southeastern Iran): Perspective from ore structures, bulk ore-rock geochemistry and O-S-Pb isotopic signatures

Hassanzadeh,

Atapour,

Ranjbar

2023

Precambrian Research

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Metasediments in the Alahina Sector and Associated Mineralization (North-Eastern Guinea)

Tchokpon¹,

Kaki²,

Adissin³

et al. 2019

OJG

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The Alahina sector is located in the NorthEast of Guinea, precisely in the Siguiri volcano-sedimentary basin. It consists mainly of meta-sediments traversed by Paleoproterozoic pyroclastite, granite, monzogranite and granodiorite veins as well as Mesozoic dolerite and gabbros veins. This article presents new data, on the one hand, on the geochemical petrographic features and the origin of the metasediments of this zone, and on the other hand, on the genetic model of the gold mineralization that they contain. Field observations, as well as petrographic and geochemical studies reveal that the meta-sediments consist of sericite and chlorite schists. They belong to the groups of shales and grauwackes. Their protholites are moderately altered (60 < CIA < 80) andesitic, basaltic and granodioritic rocks emplaced in a geotectonic oceanic island arc and/or active continental margin. Their chondrite normalized REE patterns show a moderate LREE enrichment (La N /Yb N = 6.31-13.24) and a flat heavy rare earth patterns (HREE). This spectrum is almost identical to those of the "Post-Archean average Australian Shale" and Early Proterozoic Greywackes. Two types of polyphase gold mineralization occur in the Alahina sector: disseminated and veined. They consist of particular of grains and nanoparticles pyrite associated with gold, magnetite, hematite, ilmenite. The hydrothermal alteration accompanying this mineralization consists of silica, microcline, chlorite-epidote-sericite-carbonates.

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Petrographical and geochemical signatures of the Granja paragneisses (Médio Coreaú Domain, NW Ceará, Brasil)

Cited by 3 publications

References 26 publications

Rhyacian‐Orosirian Khondalite Belt in the Borborema Province (NE Brazil): An active margin setting based on U–Pb zircon and monazite constraints

Rhyacian‐Orosirian Khondalite Belt in the Borborema Province (NE Brazil): An active margin setting based on U–Pb zircon and monazite constraints

The Ediacaran metamorphosed banded iron formation (BIF) at Gohar Zamin mine (Gol-e-Gohar #3 anomaly), Sirjan (southeastern Iran): Perspective from ore structures, bulk ore-rock geochemistry and O-S-Pb isotopic signatures

Metasediments in the Alahina Sector and Associated Mineralization (North-Eastern Guinea)

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