Assembling West Gondwana in the Neoproterozoic: Clues from the São Francisco craton region, Brazil

Alkmim, Fernando Flecha de; Marshak, Stephen; Fonseca, Marco Antônio

doi:10.1130/0091-7613(2001)029<0319:awgitn>2.0.co;2

Cited by 157 publications

(69 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hence, during the early Cenozoic, the sedimentary basins along the Equatorial Brazilian margin evolved into a pull−apart phase, as the South American plate migrated westward and northwestward (Alkmin, 2001;Costa et al, 2001;Nogueira et al 2010).…”

Section: Accepted Manuscriptmentioning

confidence: 98%

The role of tectonics in the late Quaternary evolution of Brazil's Amazonian landscape

Rossetti

2014

Earth-Science Reviews

View full text Add to dashboard Cite

Section: Accepted Manuscriptmentioning

confidence: 98%

The role of tectonics in the late Quaternary evolution of Brazil's Amazonian landscape

Rossetti

2014

Earth-Science Reviews

View full text Add to dashboard Cite

“…AGSZ Arroio Grande Shear Zone, DCSZ Dorsal de Canguçu Shear Zone, ESZ Erval Shear Zone, LRSZ Laguna Rocha Shear Zone, SBSZ Sierra Ballena Shear Zone, SYSZ Sarandí del Yí Shear Zone, VAYSZ Vila Ayrosa Galvão Shear Zone. Inlet (upper left corner): Brasiliano-Pan-African belts in West Gondwana; ages of main orogenic evolution from Machado et al (1996), Pimentel et al (1999), Hartmann et al (2000a), Alkmim et al (2001), Pedrosa-Soares et al (2001), Saalmann et al (2005a). Cratons: A Amazon, C Congo, K Kalahari, LP Rio de la Plata, PA Paraná, SF São Francisco.…”

Section: Geologic Setting: Tectonic Units Of S-brazil and Uruguaymentioning

confidence: 99%

Multiple accretion at the eastern margin of the Rio de la Plata craton: the prolonged Brasiliano orogeny in southernmost Brazil

Saalmann

Gerdes

Lahaye

et al. 2010

Int J Earth Sci (Geol Rundsch)

120

View full text Add to dashboard Cite

The Neoproterozoic-Eoplalaeozoic Brasiliano orogeny at the eastern margin of the Rio de la Plata craton in southernmost Brazil and Uruguay comprises a complex tectonic history over 300 million years. The southern Brazilian Shield consists of a number of tectono-stratigraphic units and terranes. The São Gabriel block in the west is characterized by c.760-690 Ma supracrustal rocks and calc-alkaline orthogneisses including relics of older, c. 880 Ma old igneous rocks. Both igneous and metasedimentary rocks have positive eNd(t) values and Neoproterozoic TDM model ages; they formed in magmatic arc settings with only minor input of older crustal sources. A trondhjemite from the São Gabriel block intruding dioritc and tonalitic gneisses during the late stages of deformation (D 3 ) yield an U-Pb zircon age (LA-ICP-MS) of 701 ± 10 Ma giving the approximate minimum age of the São Gabriel accretionary event. The Encantadas block further east, containing the supracrustal Porongos belt and the Pelotas batholith, is in contrast characterized by reworking of Neoarchean to Palaeoproterozoic crust. The 789 ± 7 Ma zircon age of a metarhyolite intercalated with the metasedimentary succession of the Porongos belt provides a time marker for the basin formation. Zircons of a sample from tonalitic gneisses, constituting the Palaeoproterozoic basement of the Porongos belt, form a cluster at 2,234 ± 28 Ma, interpreted as the tonalite crystallization age. Zircon rims show ages of 2,100-2,000 Ma interpreted as related to a Palaeoproterozoic metamorphic event. The Porongos basin formed on thinned continental crust in an extensional or transtensional regime between c. 800-700 Ma. The absence of input from Neoproterozoic juvenile sources into the Porongos basin strongly indicates that the Encantadas and São Gabriel blocks were separated terranes that became juxtaposed next to each other during the Brasiliano accretional events. The tectonic evolution comprises two episodes of magmatic arc accretion to the eastern margin of the Rio de la Plata craton, (i) accretion of an intra-oceanic arc at c. 880 Ma (Passinho event) and (ii) accretion of the 760-700 Ma Cambaí/Vila Nova magmatic arc (São Gabriel event). The latter event also includes the collision of the Encantadas block with the Rio de la Plata craton to the west. Collision and crustal thickening was followed by sinistral shear along SW-NE-trending orogenparallel crustal-scale shear zones that can be traced from southern Brazil to Uruguay and have been active between 660 and 590 Ma. Voluminous granitic magmatism in the Pelotas batholith spatially related to shear zones is interpreted as late-to post-orogenic magmatism, possibly assisted by lithospheric delamination. It marks the transition to the post-orogenic molasse stage. Localized deformation by reactivation of preexisting shear zones continued Electronic supplementary material The online version of this article (

show abstract

“…The study area shows interference of two distinct generations of tectonic structures associated with the West Gondwana amalgamation (Alkmim et al 2001). The NS-striking structures of the Paramirim corridor probably represent the propagation of the Araçuaí orogenic front toward the interior of São Francisco Craton, and the WSW-ESE-trending of Rio Preto Belt, the inversion of a preexistent rift structure along the NW craton margin.…”

Section: Structurementioning

confidence: 99%

Stratigraphy, tectonics and detrital zircon U-Pb (LA-ICP-MS) geochronology of the Rio Preto Belt and northern Paramirim corridor, NE, Brazil

et al. 2017

View full text Add to dashboard Cite

Two important Proterozoic metasedimentary sequences, the Rio Preto and Santo Onofre Groups, crop out along the northwestern margin of the São Francisco craton and in northern Paramirim corridor, respectively. The Rio Preto Group, involved in the eponymous fold-thrust belt along the northwestern cratonic boundary, comprises the Formosa (garnet schist, quartz-mica schist, quartzite, chlorite-sericite schist and ferriferous quartz schist) and Canabravinha (quartzite, micaceous quartzite, metarhytmite, phylite, schist and metaturbidite) formations. The Santo Onofre Group occurs exclusively in the Paramirim corridor, and is composed of quartzite and minor carbonaceous or Mn-rich phylite. These units record sedimentation in shallow to deep-water marine settings related to rift basins, and were deformed and metamorphosed under greenschist facies conditions during the Brasiliano orogeny. Here we present 427 new detrital zircon U-Pb ages, which constrain the maximum depositional ages of ca. 971 Ma for the Santo Onofre Group, ca. 912 Ma for the Canabravinha Formation, and ca. 965 Ma for the Formosa Formation of the Rio Preto Group. Our data suggests that the Santo Onofre and the Rio Preto Groups accumulated in two distinct basin settings. The latter, composed mostly of sandy rocks, would represent a relatively stable, shallow-marine shelf environment. The Rio Preto Group, with metadiamictite, quartzite, pelitic and rhythmitic rocks, represents a shallow to deep marine environment influenced by gravity flows. Both groups were probably deposited in the Late Tonian, and are potential correlatives of the lower (pre-glacial) units of the Macaú-bas Group of the Araçuaí belt. KEYWORDS:Detrital zircon U-Pb geochronology, Brasiliano orogeny, sedimentary provenance, Rio Preto Belt, Paramirim corridor. RESUMO: Duas importantes sequências metassedimentares proterozoicas ocorrem ao longo da margem noroeste do Cráton do

show abstract

Assembling West Gondwana in the Neoproterozoic: Clues from the São Francisco craton region, Brazil

Cited by 157 publications

References 13 publications

The role of tectonics in the late Quaternary evolution of Brazil's Amazonian landscape

The role of tectonics in the late Quaternary evolution of Brazil's Amazonian landscape

Multiple accretion at the eastern margin of the Rio de la Plata craton: the prolonged Brasiliano orogeny in southernmost Brazil

Stratigraphy, tectonics and detrital zircon U-Pb (LA-ICP-MS) geochronology of the Rio Preto Belt and northern Paramirim corridor, NE, Brazil

Contact Info

Product

Resources

About