The Paleoproterozoic Eastern Bahia Orogenic Domain

Barbosa, Johildo Salomão Figueirêdo; Barbosa, Rafael Gordilho

doi:10.1007/978-3-319-01715-0_4

Cited by 39 publications

(20 citation statements)

References 32 publications

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“…As implicit in its name, this orogeny spans, like the Pan‐African/Brasiliano orogen, the Atlantic Ocean (e.g., Feybesse et al, 1998; Ledru, Johan, Milési, & Tegyey, 1994; Lerouge et al, 2006; Trompette, 1994). It encompasses the whole WCAFB (e.g., Feybesse et al, 1998; Lerouge et al, 2006; Loose & Schenk, 2018; Toteu et al, 1994), its South American equivalents, such as the Eastern Bahia and Mineiro belts (e.g., Aguilar et al, 2017; Alkmim & Wilson, 2017; Barbosa & Barbosa, 2017; Carvalho, Janasi, & Sayer, 2017), and its West African counterparts, the Ashanti‐Kumasi, Houndé, Lawra, Kédougou, Ouago‐Fitini, and Reguibat belts (e.g., Kouamelan et al, 1997; Lambert‐Smith et al, 2015; Parra‐Avila et al, 2017; Peucat et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…The basement of southwestern Cameroon comprises the Ntem, Nyong, and Oubanguide complexes (e.g., Owona et al, 2011). While the Ntem Complex comprises the Cameroonian part of the Archean Congo Shield, the Nyong Complex of the WCAFB represents those parts of the Archean Shield that were remobilized during the Eburnean/Trans‐Amazonian Orogeny (Figures 1b,c and 2; e.g., Aguilar et al, 2017; Alkmim & Wilson, 2017; Barbosa & Barbosa, 2017; Feybesse et al, 1998; Neves et al, 2006; Pénaye et al, 2004). The Oubanguide Complex or North Equatorial Fold Belt, is the result of the Neoproterozoic collision between the Congo, West African, and Saharan shields (Figure 1a,b; Abdelsalam, Liégeois, & Stern, 2002; Castaing et al, 1994; Caxito et al, 2020; Feybesse et al, 1998).…”

Section: Geological Settingmentioning

confidence: 99%

“…It stretches across Cameroon, the Central African Republic, Equatorial Guinea, and Gabon, forming the West Central African Fold Belt (WCAFB; Boniface, Schenk, & Appel, 2012; Houketchang Bouyo, Pénaye, Mouri, & Toteu, 2019; Feybesse et al, 1998; Loose & Schenk, 2018; Nga Essomba et al, 2019; Thiéblemont, Callec, Fernandez‐Alonso, & Chène, 2018). Units equivalent to the Nyong Complex were mapped around the West African Shield, notably the Ashanti‐Kumasi, Houndé, Lawra, Kédougou, Ouago‐Fitini, and Reguibat belts (Kouamelan, Delor, & Peucat, 1997; Lambert‐Smith, Lawrence, Müller, & Treloar, 2015; Parra‐Avila et al, 2017; Peucat, Capdevila, Drareni, Mahdjoub, & Kahoui, 2005), and around the São Francisco Shield in Brazil, comprising the Eastern Bahia and Mineiro belts (Figure 1a; e.g., Aguilar et al, 2017; Alkmim & Wilson, 2017; Barbosa & Barbosa, 2017; Lopez, Cameron, & Jones, 2001; Neves et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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New U–Pb zircon ages of Nyong Complex meta‐plutonites: Implications for the Eburnean/Trans‐Amazonian Orogeny in southwestern Cameroon (Central Africa)

Owona

Ratschbacher

et al. 2020

Geological Journal

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ICP-MS U-Pb zircon ages from the Nyong Complex of southwestern Cameroona part of the West Central African Fold Belt-trace Late Mesoarchean (2,850 Ma), Middle Palaeoproterozoic (2,080 Ma), and Neoproterozoic (605 Ma) events: Two meta-syenites and the protolith of an amphibolite are Late Mesoarchean; two meta-granodiorites are Middle Palaeoproterozoic; the amphibolite may have recrystallized in the Middle Palaeoproterozoic; all rocks are overprinted by the Neoproterozoic event. Integration with published data shows that our amphibolite sample has one of the oldest amphiboliteprotolith ages (2,810 Ma) reported so far. It shares the Middle Palaeoproterozoic metamorphism/recrystallization with other, previously dated amphibolites. An earlier reported metamorphic zircon age (2,090 Ma) from eclogite is somewhat older than the regional Middle Palaeoproterozoic metamorphism/recrystallization ages (2,040 Ma) reported from amphibolites. Thus, the eclogite-amphibolite ages may date an exhumation process. A published charnockite age, interpreted as an Early Mesoarchean crystallization age, is older than the Late Mesoarchean meta-syenite and amphibolite-protolith dates; its Middle Palaeoproterozoic metamorphism/recrystallization age, however, is identical with the metagranodiorites and amphibolites. The Neoproterozoic ages demonstrate the regional overprint of the Nyong Complex during this period. Integration of the Nyong Complex ages with published ones from the entire West Central African Fold Belt, and comparison with those from West Africa and South America, support their common origin from the Palaeoproterozoic collision between the Archean Congo and São Francisco shields.

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Section: Discussionmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New U–Pb zircon ages of Nyong Complex meta‐plutonites: Implications for the Eburnean/Trans‐Amazonian Orogeny in southwestern Cameroon (Central Africa)

Owona

Ratschbacher

et al. 2020

Geological Journal

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“…In the northern half of the craton, a mosaic of Archean blocks comprised of the 3.4–3.2 Ga Gavião block, the 3.0–2.7 Ga Jequié block, and the 3.0–2.1 Ga Serrinha block was assembled with Paleoproterozoic, juvenile crustal segments during the 2.17–2.04 Ga Itabuna–Salvador–Curaçá orogeny (Barbosa & Barbosa, , Barbosa & Sabaté, , ; Teixeira, Oliveira, & Marques, ; Figure ). The southern part of the craton is separated from the northern part by the Paramirim Aulacogen filled with the Proterozoic rift sequences.…”

Section: The Eastern Margin Of the São Francisco Cratonmentioning

confidence: 99%

Post‐Great Oxidation Event Orosirian–Statherian iron formations on the São Francisco craton: Geotectonic implications

Rosière

Bekker

Rolim³

et al. 2019

Island Arc

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The protocratonic core of the São Francisco craton assembled during the 2.1–2.0 Ga Transamazonian orogeny. Orosirian Fe‐rich sequences that extend from the northwestern border of the São Francisco protocraton (Colomi Group) to the southeast under the Espinhaço Belt (the < 1.99 Ga Serra da Serpentina Group) record the opening of an intracratonic basin with the episodically developed ferruginous waters prior to the initiation of the Espinhaço rift at 1.8 Ga. Ferruginous conditions developed again during deposition of the Canjica Iron Formation of the < 1.7 Ga Serra de São José Group in the Espinhaço rift (contemporaneously with felsic magmatism; Conceição do Mato Dentro Rhyolite and Borrachudos Granitic Suite) and extensive sandstones of the < (1666 ±32) Ma Itapanhoacanga and < (1683 ±11) Ma São João da Chapada Formations. In the upper São João da Chapada Formation, banded hematitic phyllite also records input of Fe‐rich fluids. The young age of these iron formations with respect to the conventionally accepted 1.88 Ga age for the youngest shallow‐marine Paleoproterozoic iron formations, the apparent absence of granular facies (granular iron formations), and yet shallow‐water (above fair‐weather base) depositional environment indicate that an unusual setting developed in a large basin after the Great Oxidation Event, in the aftermath of the Transamazonian orogeny. We propose that mantle plumes led to the opening of a previously unrecognized rift system, that could have caused the magmatism, supplied hydrothermal Fe and led to the opening of the Espinhaço, Pirapora, and Paramirim rifts, later obliterated by the Araçuaí orogenic belt during the Neoproterozoic to Early Paleozoic Brasiliano orogeny. The rift system did not develop into an open continental margin but probably evolved into a broad sag basin, stretching across the São Francisco and Congo cratons.

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“…The SFC represents a crustal block underlain by Archean components that was consolidated during the Paleoproterozoic, around 2.08 Ga (Barbosa and Barbosa, 2017). It contains rocks with ages ranging between 3.4 and 1.9 Ga , which were not significantly affected by the deformation and metamorphism resulting from younger events, of Brasiliano age, during the Neoproterozoic (Barbosa and Sabaté, 2003;Cruz et al, 2016).…”

Section: Regional Geological Settingmentioning

confidence: 99%

The paleoproterozoic post-tectonic granites of the Gavião Block: the example of Salininha monzogranite, Brumado, Bahia, Brazil

Barbosa

Hamilton

Oliveira

et al. 2019

Geol. USP. Sér. Cient.

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The Gavião Block is underlain by a variety of Archean orthogneisses and greenstone belts, intruded by a suite of syn-deformational and post-tectonic granitoids which ages of emplacement are poorly constrained between the Paleoand Mesoproterozoic. The Salininha monzogranite is a massive intrusion located approximately 50 km northwest of Brumado, south-central Bahia state, Brazil. The intrusion is representative of several post-tectonic felsic plutons in the Gavião Block. Their petrology, geochemistry and age have been largely unstudied. Salininha pluton is a roughly 16 km2 irregular, elongate body intruding strongly deformed and metamorphosed orthogneisses and migmatites of the Archean Gavião Complex. Modally, the Salininha rocks contain biotite as the major ferromagnesian accessory, besides lesser hornblende, muscovite, chlorite, zircon, opaques and epidote. They are slightly peraluminous rocks with high silica contents (71.6 – 75.0wt%), obtained by lithium tetraborate fusion inductively coupled plasma (ICP). The rocks have high concentration of Rb, Sr and Ba (323,88 and 1,155 ppm, respectively). These values were obtained by lithium tetraborate fusion (mass spectrometer—MS). The average value obtained for the La/Yb ratio was 18.83. Chondrite-normalized rare earth element (REE) patterns show a smooth, restricted range, with moderate light REE enrichment, but flat heavy REE patterns — all samples show pronounced negative Eu anomalies consistent with feldspar fractionation. Major and trace elements have trends, which indicate that crystal fractionation of plagioclase, K-feldspar and biotite — an important process during magmatic evolution of the pluton. The trace element data provided support to the classification of the Salininha monzogranite as a post-collisional intrusion. A representative sample has yielded an early Orosirian U-Pb (zircon) age of 2003 ± 4 Ma, via chemical abrasion-isotope dilution-thermal ionization

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The Paleoproterozoic Eastern Bahia Orogenic Domain

Cited by 39 publications

References 32 publications

New U–Pb zircon ages of Nyong Complex meta‐plutonites: Implications for the Eburnean/Trans‐Amazonian Orogeny in southwestern Cameroon (Central Africa)

New U–Pb zircon ages of Nyong Complex meta‐plutonites: Implications for the Eburnean/Trans‐Amazonian Orogeny in southwestern Cameroon (Central Africa)

Post‐Great Oxidation Event Orosirian–Statherian iron formations on the São Francisco craton: Geotectonic implications

The paleoproterozoic post-tectonic granites of the Gavião Block: the example of Salininha monzogranite, Brumado, Bahia, Brazil

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