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Metadados | Descrição | Idioma |
---|---|---|
Autor(es): dc.creator | Lagoeiro, Leonardo Evangelista | - |
Autor(es): dc.creator | Hippertt, João | - |
Autor(es): dc.creator | Lana, Cristiano de Carvalho | - |
Data de aceite: dc.date.accessioned | 2019-11-06T13:31:11Z | - |
Data de disponibilização: dc.date.available | 2019-11-06T13:31:11Z | - |
Data de envio: dc.date.issued | 2014-11-18 | - |
Data de envio: dc.date.issued | 2014-11-18 | - |
Data de envio: dc.date.issued | 2003 | - |
Fonte completa do material: dc.identifier | http://www.repositorio.ufop.br/handle/123456789/3953 | - |
Fonte: dc.identifier.uri | http://educapes.capes.gov.br/handle/capes/557072 | - |
Descrição: dc.description | Banded iron formation (BIF) from the Quadrilátero Ferrífero (southeastern Brazil) shows a compositional layering with alternating iron-rich and quartz-rich layers. This layering was intensively folded and transposed at a centimeter/millimeter scale through a component of bedding-parallel shear related to flexural slip at middle to high greenschist facies conditions (400–450 jC). The microstructure and c-axis fabrics of normal limbs, inverted limb and hinge zones of a selected isoclinal fold were analyzed combining optical and scanning electron microscopy (SEM) and digital image analysis. In the normal limbs, recrystallized quartz grains show undulose extinction, relatively dry grain boundaries, c-axes at high angle to foliation and a pervasive grain shape fabric (GSF) indicating operation of crystal-plastic processes. In the inverted limb, quartz grains show more serrated and porous (‘‘wet’’) grain boundaries; the GSF is similar to that of the normal limb, but c-axes are oriented at 90j to those of the normal limb. We interpreted these characteristics as reflecting operation of solution-precipitation deformation in inverted limbs, as a consequence of grains having been rotated to an orientation that was hard to basal hai glide, but easy to dissolution-precipitation creep. This deformation partitioning between crystal-plasticity and solution-transfer during folding/ transposition of quartz may explain the common occurrence of layered quartz rocks, where individual layers show alternating caxis fabrics with opposite asymmetries but a consistent GSF orientation. Such characteristics may reflect an earlier event of pervasive folding/transposition of a preexisting layering. | - |
Idioma: dc.language | en | - |
Direitos: dc.rights | O Periódico Tectonophysics concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3480320613550 | - |
Palavras-chave: dc.subject | Deformation partitioning | - |
Palavras-chave: dc.subject | Microstructures | - |
Palavras-chave: dc.subject | Dissolution-precipitation creep | - |
Palavras-chave: dc.subject | Crystal-plasticity | - |
Palavras-chave: dc.subject | Foliation transposition | - |
Título: dc.title | Deformation partitioning during folding and transposition of quartz layers. | - |
Aparece nas coleções: | Repositório Institucional - UFOP |
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