Tectonic inheritances in rifts: The meaning of NNE lineaments in the continental rift of SE-Brazil

The effect of previous structures inheritance is known to be important in the development of tectonic rifts. A series of overlapping structures generally can be represented by lineaments marking the successive tectonic events. We studied the NNE structural lineaments corridor in the central region o...

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Veröffentlicht in:Journal of South American earth sciences 2021-06, Vol.108, p.103225, Article 103225
Hauptverfasser: Giro, João Paulo, Almeida, Julio, Guedes, Eliane, Bruno, Henrique
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Sprache:eng
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Zusammenfassung:The effect of previous structures inheritance is known to be important in the development of tectonic rifts. A series of overlapping structures generally can be represented by lineaments marking the successive tectonic events. We studied the NNE structural lineaments corridor in the central region of the Ribeira Belt. We used a digital elevation model (DEM) and new and previous fieldwork data to investigate the structural control of such lineaments and their relevance for the Brazilian continental margin. Our results suggest that the NNE direction is a crustal weakness zone characterising corridors of intense ductile and brittle deformation which was recurrently reactivated. Aligned NNE Neoproterozoic-Ordovician ductile and brittle structures as foliations, shear zones, lithological boundaries, and fractures filled by pegmatitic veins coincide with the lineaments. During the Cretaceous rift, a transtensional sinistral regime generated NNE T-fractures filled by mafic dykes. In the Cenozoic, the NNE direction is represented by transfer and domino faults developed within a mega accommodation zone in an intracontinental rift system. Our results suggest that the NNE direction was active in this region throughout the Phanerozoic and has high relevance for the structural development of the continental margin of southeastern Brazil. •Geotectonic differences between the Ribeira Belt's terranes led to a distinct ductile deformation.•Sinistral transtensional regime, mafic dykes, and riedel fractures associated with the Gondwana break-up.•Brittle deformation geometry and kinematic evolution of riedel shear fractures during the Cretaceous and Cenozoic.
ISSN:0895-9811
1873-0647
DOI:10.1016/j.jsames.2021.103225