Tectônica proterozóica no alto e médio Vale do Ribeira, estados de São Paulo e Paraná

Campanha, Ginaldo Ademar da Cruz

doi:10.11606/t.44.1992.tde-13032013-115922

Cited by 59 publications

(147 citation statements)

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“…Regional metamorphism is in the chlorite to biotite zones of the greenschist facies (Table 1). This succession is similar to that described by Souza (1990) and Reis Neto (1994) who also considered that the Água Clara Formation (SE of Itapirapuã Shear Zone), usually con- Campanha, 1991;Basei et al, 1992;Siga Jr, 1995;Campos Neto, 2000 In the basal unit, metamorphosed feldspathic sandstones predominate, and contain interbedded metavolcanic and metavolcanoclastic rocks. Graded and cross beddings are preserved in the metasandstones, which are immature, rich in quartz and microcline clasts, suggesting that the source area was granitic.…”

Section: Geol Geol Geol Geol Geological Fea Ogical Fea Ogical Fea Ogisupporting

confidence: 85%

U-Pb (Zircon) ages of metavolcanic rocks from the Itaiacoca Group: tectonic implications

Siga

Basei

Sato

et al. 2003

Geol. USP, Sér. cient.

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The main aim of this work is to present and discuss the U-Pb ages obtained for zircon grains from metavolcanic rocks of the Itaiacoca Group. The Itaiacoca Group is a metavolcano-sedimentary sequence, which occurs as a narrow belt between the Cunhaporanga granitic batholith to the northwest and the Itapirapuã shear zone to the south and southwest, which separates the sequence from the Três Córregos granite batholith and metasedimentary rocks of the Açungui Group. Geological studies of the southern part of the Itaiacoca belt led to the recognition of three units, represented (from base to top) by metawackes with an important volcanic component, metacarbonate, and metapelitic and metapsammitic rocks. The U-Pb geochronological analyses of zircon grains from two outcrops of metavolcanic rocks yield ages of 628 ± 18 Ma (SHRIMP) and 636 ± 30 Ma (conventional multigrain analyses). These ages are quite close to the metamorphic event recorded in the Itaiacoca Group (628 -610 Ma), suggesting a short interval between the formation of these rocks and closure of the basin. Furthermore, this volcanism is very close to the age of formation of the Três Córregos (630 Ma) and Cunhaporanga (590 Ma) granitic batholiths, admitted as associated with a probable magmatic arc. Such an isotopic pattern characterizes a Neoproterozoic tectonic scenario involving volcanism, metamorphism and granitic plutonism, interpreted here as the final stages in the evolution of the Itaiacoca Basin.Palavras-chave: U-Pb (zircões), seqüências metavulcano-sedimentares, evolução tectônica. RESUMOO objetivo principal deste trabalho é apresentar e discutir as idades geocronológicas U-Pb, em zircões de rochas metavulcânicas pertencentes ao Grupo Itaiacoca. Este é representado por uma seqüência metavulcano-sedimentar, que ocorre como uma faixa relativamente estreita, limitada a norte pelo Batólito Granítico Cunhaporanga, sendo balizada a sul, através da Zona de Cisalhamento Itapirapuã, pelo Batólito Granítico Três Córregos e pelos metassedimentos do Grupo Açungui. Os estudos geológicos efetuados na porção sul da Faixa Itaiacoca permitiram reconhecer três unidades geológicas maiores, representadas, da base para o topo, por metarcóseos (com importante contribuição vulcânica-vulcanoclástica), rochas metacarbonáticas e rochas metapelíticas-metapsamíticas. Análises geocronológicas U-Pb realizadas em zircões de dois afloramentos de rochas metavulcânicas, forneceram idades de 628 ± 18 Ma (SHRIMP) e 636 ± 30 Ma (convencional). O metamorfismo dessas rochas parece ter ocorrido em épocas bastante próximas (628 -610 Ma) à cristalização dos zircões, sugerindo curto intervalo de tempo entre o vulcanismo estudado e os episódios de fechamento da bacia. Não obstante, as idades obtidas também se aproximam da época de formação dos batólitos graníticos Três Córregos (630 Ma) e Cunhaporanga (590 Ma), admitidos como prováveis arcos magmáticos. Tal padrão isotópico caracteriza um cenário tectônico Neoproterozóico envolvendo vulcanismo, metamorfismo e plutonismo granítico, inte...

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Section: Geol Geol Geol Geol Geological Fea Ogical Fea Ogical Fea Ogisupporting

confidence: 85%

U-Pb (Zircon) ages of metavolcanic rocks from the Itaiacoca Group: tectonic implications

Siga

Basei

Sato

et al. 2003

Geol. USP, Sér. cient.

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“…1) lying within the "Ribeira Fold Belt," an orogenic belt of Neo-to Mesoproterozoic age on the east coast of Brazil (Almeida, 1977). Supracrustal rocks of a low to medium degree of metamorphism, known as the Açungui Supergroup, are predominant in this area (Campanha, 1991;Campanha & Sadowski, 1999).…”

Section: Structural and Hydrological Controls In The Development Of Amentioning

confidence: 99%

“…It is composed of fine-grained, white, homogeneous metadolomites (Campanha et al, 1985) (Fig. 2) with an apparent thickness of up to 500 m. Along with underlying phyllites, schists and quartzites (Metapelitic Unit), the marble composes the Serra das Andorinhas Sequence (Faleiros et al, 2012), forming a large synformal structure delimited by transcurrent faults (Neoproterozoic-Eopaleozoic) (Campanha, 1991(Campanha, , 2002.…”

Section: Structural and Hydrological Controls In The Development Of Amentioning

confidence: 99%

Structural and hydrological controls on the development of a river cave in marble (Tapagem Cave, SE Brazil)

Filho¹,

Cordeiro²,

Karmann³

2015

IJS

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Abstract:Tapagem Cave (or Devil's Cave) is a river cave developed in the dolomite marble karst of the Serra do André Lopes (State of São Paulo, southeastern Brazil). Although this region is a plateau with significant variation in elevation and a humid subtropical climate, the cave is an anomalous feature in the André Lopes karst because there are few other caves. The marble, which is in a synclinal structure with subjacent phyllites, is a karst aquifer perched above the regional base level (Ribeira River) and has little allogenic recharge. The cave developed on a secondary anticline on the northwest flank of the marble synform forming a blind valley, the Tapagem River sink, that is an underground tributary of Ostras River. Development of the cave is due to the entrenchment of the Ostras through-valley and the large allogenic catchment area of the sink. In plan view, the morphology of the cave can be divided into three different sectors. The first sector, known as the Tourist Sector, has extensive collapse rooms, fossil passages and a variety of speleothems of notable dimensions. The second and most extensive sector is the river passage, which is a sinuous gallery controlled by marble banding with NE-SW cleavage and NW-SE fractures. In cross-section, the passages are vadose canyons up to 70 m in height, controlled by the marble banding. Four NW-SE diabase dykes in this passage do not affect its direction in plan view. The third sector is an extensive network of passages and collapse rooms, which are interlaced in plan view and on different levels, forming a maze pattern. Initially, the Tapagem and Ostras Rivers developed on a gentle surface and flowed into the Ribeira River. With the entrenchment of the Ostras through-valley, the Tapagem River partially infiltrated via a paleosink into the upper passage of the "Erectus Room," remaining a half-blind valley. Following a series of collapses and obstructions, the River next infiltrated via the current sink, creating a fully blind valley. Currently, the cave has a difference in elevation of 120 m between the sink and the resurgence, which corresponds to the difference in entrenchment between the two valleys.marble, through valley, river cave, cave morphology, Tapagem Cave, Brazil

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“…Planaltos cársticos caracterizados por mosaicos de depressões poligonais recobertos por floresta atlântica ocorrem na Serrania Costeira do Sul do Estado de São Paulo; estão associados a uma faixa dobrada proterozóica compartimentada em blocos tectônicos seguindo um sistema de zonas de cisalhamento transcorrentes com direções NE-SW (Campanha, 1992). O planalto Lajeado-Bombas no municí-pio de Iporanga -SP, com 38 km 2 de superfície encontra-se neste contexto (Figura 1).…”

Section: áRea De Estudounclassified

Comportamento hidrodinâmico de sistemas cársticos na bacia do rio Betari, Município de Iporanga - SP

Ferrari

Karmann

2008

Geol. USP, Sér. cient.

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Tectônica proterozóica no alto e médio Vale do Ribeira, estados de São Paulo e Paraná

Cited by 59 publications

References 0 publications

U-Pb (Zircon) ages of metavolcanic rocks from the Itaiacoca Group: tectonic implications

U-Pb (Zircon) ages of metavolcanic rocks from the Itaiacoca Group: tectonic implications

Structural and hydrological controls on the development of a river cave in marble (Tapagem Cave, SE Brazil)

Comportamento hidrodinâmico de sistemas cársticos na bacia do rio Betari, Município de Iporanga - SP

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