Ediacaran post-collisional K-rich granitic magmatism within the Major Gercino Shear Zone, Southern Brazil: An example of prolonged magmatism and differentiation under active transcurrent tectonism

Lithos ◽  
2021 ◽  
pp. 106341
Author(s):  
Felipe Manfredini Peruchi ◽  
Luana Moreira Florisbal ◽  
Maria de Fátima Bitencourt ◽  
Dionatan Ferri Padilha ◽  
Lauro Valentim Stoll Nardi
2017 ◽  
Vol 75 ◽  
pp. 116-133 ◽  
Author(s):  
Jefferson V. de Lima ◽  
Ignez de P. Guimarães ◽  
Lucilene Santos ◽  
José Victor A. Amorim ◽  
Douglas José S. Farias

Tectonics ◽  
1994 ◽  
Vol 13 (2) ◽  
pp. 421-437 ◽  
Author(s):  
Andréa Tommasi ◽  
Alain Vauchez ◽  
Luis A. D. Femandes ◽  
Carla C. Porcher

2020 ◽  
Vol 136 ◽  
pp. 104058 ◽  
Author(s):  
G.B. De Toni ◽  
M.F. Bitencourt ◽  
J. Konopásek ◽  
A. Martini ◽  
P.H.S. Andrade ◽  
...  

2011 ◽  
Vol 32 (4) ◽  
pp. 369-378 ◽  
Author(s):  
Cláudia Regina Passarelli ◽  
Ian McReath ◽  
Miguel Ângelo Stipp Basei ◽  
Oswaldo Siga ◽  
Mário da Costa Campos Neto
Keyword(s):  

2000 ◽  
Vol 137 (1) ◽  
pp. 39-51 ◽  
Author(s):  
ALAN S. COLLINS ◽  
THEODORE RAZAKAMANANA ◽  
BRIAN F. WINDLEY

A laterally extensive, Neoproterozoic extensional detachment (the Betsileo shear zone) is recognized in central Madagascar separating the Itremo sheet (consisting of Palaeoproterozoic to Mesoproterozoic sediments and underlying basement rocks) from the Antananarivo block (Archaean/Palaeoproterozoic crust re-metamorphosed in the Neoproterozoic). Non-coaxial deformation gradually increases to a maximum at a lithological contrast between the granitoids and gneisses of the footwall and the metasedimentary rocks of the hangingwall. Ultramylonites at this highest-strained zone show mineral-elongation lineations that plunge to the southwest.σ-, δ- and C/S-type fabrics imply top-to-the-southwest extensional shear sense. Contrasting metamorphic grades are found either side of the shear zone. In the north, where this contrast is greatest, amphibolite-grade footwall rocks are juxtaposed with lower-greenschist-grade hangingwall rocks. The metamorphic grade in the hangingwall increases to the south, suggesting that a crustal section is preserved.The Betsileo shear zone facilitated crustal-scale extensional collapse of the East African Orogeny, and thus represents a previously poorly recognized structural phase in the story of Gondwanan amalgamation. Granitic magmatism and granulite/amphibolite-grade metamorphism in the footwall are all associated with formation of the Betsileo shear zone, making recognition of this detachment important in any attempt to understand the tectonic evolution of central Gondwana.


2004 ◽  
Vol 55 ◽  
Author(s):  
Renata De P.X. MORO ◽  
Benjamim Bley de Brito NEVES

A Formação Camarinha constitui uma unidade sedimentar do final do Neoproterozóico no centro-leste do Estado do Paraná, em contato por falha e discordância com unidades metamórficas do Cinturão Ribeira, este último representado pelas formações Água Clara, Votuverava e Capiru. Na região, ocorrem também o Complexo Atuba, Núcleo Betara (ambos paleoproterozóicos) e o Complexo Granítico Três Córregos, de idade Neoproterozóica. A oeste, a formação é recoberta discordantemente por rochas sedimentares devonianas da Bacia do Paraná (Formação Furnas). A Formação Camarinha é constituída por conglomerados, brechas, arenitos, siltitos, lamitos e ritmitos imaturos, medianamente a mal selecionados, distribuídos em três unidades denominadas A, B e C, com contatos transicionais entre si, sendo as unidades A e C de natureza predominantemente psamo-pelítica, e a unidade B de natureza conglomerática, depositadas em sistemas de leques progradantes e retrogradantes de ambientes costeiros (fandeltas). As áreas-fonte dos sedimentos são representadas pelas formações Água Clara, Votuverava e Capiru e pelos complexos Atuba e Três Córregos, sendo que a deposição processou-se em ambiente tardi a pós-orogênico com relação à Orogênese Brasiliana, antes das manifestações magmáticas pós-orogênicas representadas pelos granitos alcalinos e pelas rochas vulcano-sedimentares das bacias de Castro e Guaratubinha. As rochas da Formação Camarinha encontram-se deformadas por um evento que também gerou a Zona de Cisalhamento Transcorrente da Falha da Lancinha, com deslocamento lateral direito, e dobramentos abertos, sistemas de fraturas e estiramento de clastos. A formação encontra-se atualmente preservada em duas faixas com dobras na forma de sinclinais, um dos quais relacionado à Falha da Lancinha, constituindo remanescentes da bacia original, sem preservação dos limites originais da bacia em que foi depositada. EXPLANATORY NOTES OF THE GEOLOGICAL MAP OF CAMARINHA FORMATION - PR Abstract The Camarinha Formation (central-eastern part of the State of Paraná, southern Brazil) is a late Proterozoic unit which has a faulted and discordant contact with older Proterozoic metasedimentary rocks of the Ribeira Belt (Água Clara, Votuverava and Capiru formations), close to the Atuba, Betara and Três Córregos complexes. On its western side, it is unconformably covered by Devonian basal strata of the Paraná Basin (Furnas Formation). The Camarinha Formation consits of poorly sorted immature rocks, such as conglomerates, breccias, sandstones, siltstones, mudstones and rhytmites, grouped into three units (A, B, and C) with transitional contacts. A and C units are sandy and muddy, and B unit is conglomeratic. These units were deposited by processes that are common in prograding and retrograding fans in coastal environments (fandeltas). The source areas are represented by the Água Clara, Votuverava and Capiru formations, and Atuba and Três Córregos complexes. The basin was formed in a late-to-post orogenic environment related to the Brasiliano Orogeny, just before postorogenic alkaline magmatic intrusions and volcanic-sedimentary rocks of the Castro and Guaratubinha basins. The rocks of Camarinha Formation are deformed related to the Lancinha Shear Zone, whose right-lateral movement generated associated folds and fractures. The formation is preserved as remains of the original basin, in two folded zones forming synclines, one of which is related to the Lancinha Shear Zone. The original borders of the basin are not preserved.


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