Transpressive dextral shear in the Italva-Itaperuna section, Northern State of Rio de Janeiro, Brazil

Anais da Academia Brasileira de Ciências

Tiago R. Karniol²  Rômulo Machado¹  Nolan M. Dehler¹ 

[1] ,Universidade de São Paulo Instituto de Geociências São Paulo SP ,Brasil

关键词: Ribeira Belt;    kinematics;    transpression;    syncontractional extension;    Cinturão Ribeira;    cinemática;    transpressão;    extensão sincontracional;   

DOI  :  10.1590/S0001-37652008000300016

来源: SciELO

【 摘 要 】

Structural analysis carried out on a segment of the Neoproterozoic Ribeira Belt, southeastern Brazil, show that it represents part of the transpressive dextral orogen related to the Central Mantiqueira Province. NNE-trending and steeply dipping regional mylonitic belts form anastomosed geometry, and describe a map-scale, S-C-like structure that is characterized by their deflection towards NE near the Além Paraíba Lineament. Lithological and structural control related to deformation partition were responsible for the formation of felsic mylonitic granulites with S-type granites lenses developed in ductile shear zones, alternated with less deformed intermediate to basic granulites associated with charnockites. The dextral shear sense indicators are consistent with transpressive deformation in the region and are common especially at the border of the main shear zones. The presence of S-type leucogranite may lead to variations of linear and planar relationships, which result in local extension zones. These elements are consistent with oblique continental collision considering the São Francisco Craton as a stable block.

【 授权许可】

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