Tectonic evolution of the Sergipano Fold Belt, NE Brazil, during the Brasiliano orogeny

The Rio Preto fold belt borders the northwestern São Francisco craton and shows an exquisite kilometric doubly-vergent asymmetric fan structure, of polyphasic structural evolution attributed exclusively to the Brasiliano Orogeny (∼600-540 Ma). The fold belt can be subdivided into three structural compartments: The Northern and Southern compartments showing a general NE-SW trend, separated by the Central Compartment which shows a roughly E-W trend. The change of dip of S2, a tight crenulation foliation which is the main structure of the fold belt, between the three compartments, characterizes the fan structure. The Central Compartment is characterized by sub-vertical mylonitic quartzites, which materialize a system of low-T strike slip shear zones (Malhadinha – Rio Preto Shear Zone) crosscutting the central portion of the fold belt. In comparison to published analog models, we consider that the unique structure of the Rio Preto fold belt was generated by the oblique, dextral-sense interaction between the Cristalândia do Piauí block to the north and the São Francisco craton to the south.

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U-Pb zircon ages, geochemical and Sr-Nd-Hf isotopic compositions of granitoids in western Songpan-Garze fold belt: Petrogenesis and implication for tectonic evolution

Journal of Earth Science ◽

10.1007/s12583-009-0054-8 ◽

2009 ◽

Vol 20 (4) ◽

pp. 681-698 ◽

Cited By ~ 9

Author(s):

Hongming Cai ◽

Hongfei Zhang ◽

Wangchun Xu

Keyword(s):

Tectonic Evolution ◽

Fold Belt ◽

Isotopic Compositions

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Deciphering superimposed Ellesmerian and Eurekan deformation, Piper Pass area, northern Ellesmere Island (Nunavut)

Canadian Journal of Earth Sciences ◽

10.1139/e07-025 ◽

2007 ◽

Vol 44 (10) ◽

pp. 1439-1452 ◽

Cited By ~ 16

Author(s):

Karsten Piepjohn ◽

Werner von Gosen ◽

Solveig Estrada ◽

Franz Tessensohn

Keyword(s):

Fault Zone ◽

Tectonic Evolution ◽

Canadian Arctic ◽

Ellesmere Island ◽

Thrust Faults ◽

Fold Belt ◽

Sverdrup Basin

The tectonic evolution in the Piper Pass area in northern Ellesmere Island (Canadian Arctic) is characterized by the superimposition of two major deformational events: the Paleozoic Ellesmerian Orogeny and the Tertiary Eurekan deformation. It is difficult to separate the structures formed during each deformation in the parts of the Canadian Arctic in which the post-Ellesmerian and pre-Eurekan Sverdrup Basin is not preserved (Hazen Fold Belt, Central Ellesmere Fold Belt). In the vicinity of the Lake Hazen Fault Zone in the Piper Pass area, kilometre-scale kink folds, cleavage planes and SSE-directed thrust faults are unconformably overlain by Permian through Tertiary rocks of the Sverdrup Basin, which clearly indicates that they are related to the Ellesmerian Orogeny. However, the steep faults of the Lake Hazen Fault Zone are characterized by possible lateral movements and by NNW–SSE compression that cut through or affect both the pre-Ellesmerian Franklinian strata, as well as the post-Ellesmerian Sverdrup Basin deposits. These structures can clearly be assigned to post-mid Cretaceous movements of the Eurekan deformation. The Piper Pass area is a key area in which it is possible to recognize and distinguish Ellesmerian from Eurekan structures.

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ARCABOUÇO TECTÔNICO E ESTRATIGRÁFICO DA FAIXA RIACHO DO PONTAL, DIVISA PERNAMBUCO-PIAUI-BAHIA

Revista Geonomos ◽

10.18285/geonomos.v21i2.269 ◽

2013 ◽

Cited By ~ 7

Author(s):

Fabrício de Andrade Caxito ◽

Alexandre Uhlein

Keyword(s):

Plate Tectonics ◽

Central Zone ◽

Fold Belt ◽

Northern Margin ◽

External Zone ◽

Metasedimentary Rocks ◽

Late Neoproterozoic ◽

Brasiliano Orogeny ◽

Augen Gneiss ◽

Ocean Ridge

A faixa brasiliana Riacho do Pontal bordeja a margem norte do Cráton do São Francisco e pode ser subdividida em três domíniosou zonas tectônicas de características geológicas contrastantes, de norte para sul: zonas Interna, Central, e Externa. A Zona Interna édominada por rochas metavulcanosedimentares intrudidas por rochas plutônicas relacionadas à Orogênese Cariris Velhos (augen-gnaissesda Suíte Afeição, ~1.0-0.9 Ga). A Zona Central é caracterizada pelo Complexo Monte Orebe, composto por metabasaltos de geoquímicasimilar aos basaltos de cadeia oceânica e rochas metassedimentares de ambiente marinho profundo. A Zona Externa é caracterizada pelosistema de nappes Casa Nova, composto por duas unidades: A Formação Barra Bonita na base, que representa uma sequência plataformaldesenvolvida na borda norte do paleocontinente São Francisco; e a Formação Mandacaru no topo, que representa uma sequência marinhaprofunda turbidítica, provavelmente sin-orogênica. Essas rochas foram afetadas por deformação compressiva (D1-D2-D3) com odesenvolvimento do sistema de nappes vergentes para sul, durante o Neoproterozoico (~630-575 Ma), seguida por deformaçãotranscorrente (D4) nos estágios tardios da Orogênese Brasiliana. Toda a faixa é intrudida por múltiplas gerações de plútons graníticos esieníticos sin a pós-colisionais, de idade neoproterozóica a cambriana (~630-530 Ma). A Faixa Riacho do Pontal representa um ciclo deplacas tectônicas completo no Neoproterozoico tardio, envolvendo a colisão do cráton do São Francisco a sul com os blocos litosféricos daProvíncia Borborema a norte.Palavras chave: Orogênese Brasiliana, Faixa Riacho do Pontal, Cráton do São Francisco ABSTRACTTECTONIC AND STRATIGRAPHIC FRAMEWORK OF THE RIACHO DO PONTAL FOLD BELT, PERNAMBUCO-PIAUI-BAHIA BORDER.The Riacho do Pontal Fold Belt borders the northern margin of the São Francisco Craton and can be subdivided into three tectonic domainsor zones of distinct geology, from north to south: the Internal, Central, and External zones. The Internal Zone is composed bymetavulcanosedimentary rocks intruded by plutonic rocks related to the Cariris Velhos Orogeny (Afeição Suite augen-gneiss, ~1.0-0.9 Ga);rocks of this age are absent in the other zones. The Central Zone is characterized by the Monte Orebe Complex, composed by metabasaltswhose geochemistry is similar to mid-ocean ridge basalts and deep marine metasedimentary rocks. The External Zone is characterized bythe Casa Nova nappe system, composed by two units: (a) the Barra Bonita Formation at the base, representing a platformal sequencedeveloped at the northern São Francisco Craton margin; and (b) the Mandacaru Formation at the top, which represents a syn-orogenicdeep marine unit. These rocks were affected by compressive deformation (D1-D2-D3) with the development of a south-verging nappesystem, during the Neoproterozoic (~630-575 Ma), followed by strike-slip deformation (D4) at the late stages of the Brasiliano Orogeny.The whole fold belt is intruded by multiple generations of syn- to post-collisional granitic and syenitic plutons, of Neoproterozoic toCambrian age (~630-530 Ma). The Riacho do Pontal Fold Belt represents a complete plate tectonics cycle at the late Neoproterozoic,involving the collision of the São Francisco Craton to the South with the crustal blocks of the Borborema Province towards North.Keywords: Brasiliano Orogeny, Riacho do Pontal Fold Belt, São Francisco Craton

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