Close spatial relationship between plutons and shear zones

Weinberg, Roberto Ferrez; Sial, Alcídes N.; Mariano, Gorki

doi:10.1130/g20290.1

Cited by 118 publications

(70 citation statements)

References 25 publications

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“…While, 1973While, , 1977Urai et al, 1986;Vernon, 2000;Hirth et al, 2001;Stipp et al, 2002;Passchier & Trouw, 2005;Zibra et al, 2010Zibra et al, , 2012Zibra, 2012). A close spatial and temporal relationship between pluton emplacement and shear zones has been documented in various geological settings (see Rosenberg, 2004 for a review; Weinberg et al, 2004). Shear zones display microstructurally very different strain anisotropy to protoliths.…”

Section: Introductionmentioning

confidence: 99%

Evidence of Quartz, Feldspar and Amphibole Crystal Plastic Deformations in the Paleoproterozoic Nyong Complex Shear Zones Under Amphibolite to Granulite Conditions (West Central African Fold Belt, SW Cameroon)

Owona¹,

Ondoa²,

Ekodeck³

2013

JGG

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The Paleoproterozoic is characterised by a global-scale period of crust formation, extensive mafic to granitic magmatism, crustal reworking and intracrustal partial melting. Since a dramatic strength drop is associated with the presence of melt in crystallising or melting rocks, Paleoproterozoic continental deformation is thought to have been largely accommodated by shearing of high-grade gneisses and syntectonic granitoids. The Paleoproterozoic Nyong complex, which is made up of volumetrically dominant granitoids, metapelites and granitic gneisses, quartzites and banded iron formations; has been affected by the Eburnean/Transamazonian polyphase ductile and brittle deformation responsible of S 1/2 foliation and S 2 schistosity, L 2 stretching and mineral lineations, F 3 meso-and large-scale folds, S 2 /C 3 structures and faults. Its shear zone strain anisotropies represent a natural laboratory to study the effect of crystal plastic deformation of felsic minerals and amphibole as predicted by numerical experiments and tectonic models. This paper describes the geometry of the deformation and focus on microstructural evidence of dynamic recrystallization features that were active under granulite conditions (>800 °C, >8.5 Kbar). These thermal conditions can be extended in similar Proterozoic worldwide shear zones.

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Section: Introductionmentioning

confidence: 99%

Evidence of Quartz, Feldspar and Amphibole Crystal Plastic Deformations in the Paleoproterozoic Nyong Complex Shear Zones Under Amphibolite to Granulite Conditions (West Central African Fold Belt, SW Cameroon)

Owona¹,

Ondoa²,

Ekodeck³

2013

JGG

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“…The confluence of shear zones, like SBSZ and CSZ in case of the Aiguá Batholith, could be a major factor controlling magma ascent and creating the space for the emplacement of large volumes of granitic magma, as pointed out for the Borborema Province in Brazil (Neves et al 1996(Neves et al , 2000Weinberg et al 2004).…”

Section: Lithologiesmentioning

confidence: 99%

The Sierra Ballena Shear Zone in the southernmost Dom Feliciano Belt (Uruguay): evolution, kinematics, and deformation conditions

Oyhantçabal

Siegesmund

Wemmer

et al. 2009

Int J Earth Sci (Geol Rundsch)

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The Sierra Ballena Shear Zone (SBSZ) is part of a high-strain transcurrent system that divides the Neoproterozoic Dom Feliciano Belt of South America into two different domains. The basement on both sides of the SBSZ shows a deformation stage preceding that of the transcurrent deformation recognized as a high temperature mylonitic foliation associated with migmatization. Grain boundary migration and fluid-assisted grain boundary diffusion enhanced by partial melting were the main deformation mechanisms associated with this foliation. Age estimate of this episode is [658 Ma. The second stage corresponds to the start of transpressional deformation and the nucleation and development of the SBSZ. During this stage, pure shear dominates the deformation, and is characterized by the development of conjugate dextral and sinistral shear zones and the emplacement of syntectonic granites. This event dates to 658-600 Ma based on the age of these intrusions. The third stage was a second transpressional event at about 586 to \560 Ma that was associated with the emplacement of porphyry dikes and granites that show evidence of flattening. Deformation in the SBSZ took place, during the late stages, under regional low-grade conditions, as indicated by the metamorphic paragenesis in the supracrustals of the country rocks. Granitic mylonites show plastic deformation of quartz and brittle behavior of feldspar. A transition from magmatic to solid-state microstructures is also frequently observed in syntectonic granites. Mylonitic porphyries and quartz mylonites resulted from the deformation of alkaline porphyries and quartz veins emplaced in the shear zone. Quartz veins reflect the release of silica associated with the breakdown of feldspar to white mica during the evolution of the granitic mylonites to phyllonites, which resulted in shear zone weakening. Quartz microstructures characteristic of the transition between regime 2 and regime 3, grain boundary migration and incipient recrystallization in feldspar indicate deformation under lower amphibolite to upper greenschist conditions (550-400°C). On the other hand, the mylonitic porphyries display evidence of feldspar recrystallization suggesting magmatic or high-T solid-state deformation during cooling of the dikes.

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“…A zona estudada funcionou como uma componente antitética do regime regional destral relacionado às zonas de cisalhamento regionais Major Gercino e Itajaí-Perimbó, resultando em uma componente de abertura. Casos semelhantes a esse, onde ocorrem zonas antitéticas com componentes de abertura, são descritos na província Borborema (Weinberg et al, 2004).…”

Section: Considerações Finais E Conclusõesunclassified

Caracterização cinemática de uma zona de cisalhamento transcorrente de direção NNE marcada na evolução de seu magmatismo granítico sintectônico na região de Camboriú, SC

Martini

Bitencourt

2014

Geol. USP, Sér. cient.

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Disponível on-line no endereço www.igc.usp.br/geologiausp -61 -Resumo O Granito Corre-mar (GCM) localiza-se na região de Itapema-Camboriú, Santa Catarina, extremo nordeste do Cinturão Dom Feliciano. Uma zona de cisalhamento subvertical de direção NNE controla seu posicionamento, gerando um par S-C subvertical com cinemática sinistral. A foliação S (magmática), de direção NE-SW, é dada principalmente pela orientação de feldspatos e xenólitos, enquanto a foliação C (cisalhamento), de direção NNE-SSW, é marcada pelo estiramento dos cristais e formação de caudas de recristalização assimétricas nos feldspatos. Nas rochas encaixantes, próximo aos contatos, desenvolvem-se zonas de deformação de baixa temperatura paralelas à foliação C local do GCM. Os corpos do GCM têm uma sistemática variação na espessura, onde zonas mais largas mostram as foliações menos desenvolvidas. Microestruturas indicativas de deformação progressiva em temperatura decrescente são representadas por subgrãos em padrão tabuleiro de xadrez no quartzo e textura granoblástica em K-feldspato, as quais são superpostas por estruturas de mais baixa temperatura, como recristalização fina do quartzo, selamento de fraturas dos cristais maiores de feldspato por material da matriz finamente recristalizada e neoformação de grãos finos ao redor dos cristais de feldspato. A integração dos dados estruturais e petrológicos indica que o GCM se posicionou quando a zona de cisalhamento NNE estava ativa, e sua geometria indica uma componente de abertura na direção NE, típica de regime transtrativo. A estrutura transtrativa é compatível com sua posição em zona de baixa deformação transcorrente do Cinturão de Cisalhamento Sul-brasileiro, situada entre as zonas de mais alta deformação representadas pela zonas de cisalhamento Major Gercino e Itajaí, ativas no estágio pós-colisional do Ciclo Brasiliano no sul do Brasil.Palavras-chave: Zona de cisalhamento transcorrente; Magmatismo granítico; Sintectônico. AbstractThe Corre-mar Granite (GCM) is located in the region of Itapema-Camboriu, Santa Catarina, Brazil, in the northeastern part of Dom Feliciano Belt. A subvertical NNE-trending shear zone controls its emplacement, and a subvertical S-C fabric is generated with sinistral shear sense. The S-planes (magmatic) strike NE-SW and are marked mainly by the orientation of feldspar crystals and xenoliths, while the C-planes (shearing), strike NNE-SSW, marked by mineral stretching, tails of asymmetric recrystallization in feldspars, and inflection of the structures previously oriented along S. Low-temperature deformation zones parallel to the GCM local C-foliation, best developed near the contacts with the host rocks, do not extend more than a few meters into the country rocks. The GCM bodies have a systematic variation in thickness, where wider zones show the least developed foliations. Microstructures indicative of progressive deformation under decreasing temperature are represented by chessboardpattern subgrains in quartz, and granoblastic K-feldspar grains. These are overprin...

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Close spatial relationship between plutons and shear zones

Cited by 118 publications

References 25 publications

Evidence of Quartz, Feldspar and Amphibole Crystal Plastic Deformations in the Paleoproterozoic Nyong Complex Shear Zones Under Amphibolite to Granulite Conditions (West Central African Fold Belt, SW Cameroon)

Evidence of Quartz, Feldspar and Amphibole Crystal Plastic Deformations in the Paleoproterozoic Nyong Complex Shear Zones Under Amphibolite to Granulite Conditions (West Central African Fold Belt, SW Cameroon)

The Sierra Ballena Shear Zone in the southernmost Dom Feliciano Belt (Uruguay): evolution, kinematics, and deformation conditions

Caracterização cinemática de uma zona de cisalhamento transcorrente de direção NNE marcada na evolução de seu magmatismo granítico sintectônico na região de Camboriú, SC

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