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Continental-scale structural heritage from rift extension to postrift inversion: Implications for the central Brazilian Equatorial Margin evolution

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DOI

  • Aline C. Tavares, Universidade Federal do Rio Grande do Norte
    • ,
  • David L. de Castro, Universidade Federal do Rio Grande do Norte
    • ,
  • Ole R. Clausen
  • Francisco H.R. Bezerra, Universidade Federal do Rio Grande do Norte
    • ,
  • Maria O.L. Sousa, Universidade Federal do Rio Grande do Norte
    • ,
  • Moab P. Gomes, Universidade Federal do Rio Grande do Norte
    • ,
  • Helenice Vital, Universidade Federal do Rio Grande do Norte
    • ,
  • Diógenes C. de Oliveira, Universidade Federal do Rio Grande do Norte

The link between major basement anisotropies and basin evolution is crucial for understanding the role of tectonic inheritance on continental margins. However, it is still a matter of debate how and why it happens, especially in the Equatorial Atlantic, where the interplay between Precambrian fabric and the shearing of major oceanic fractures has been studied. Here, we investigate the offshore Ceará Basin and its basement in the central part of the Brazilian Equatorial Margin to (1) map basement anisotropies underneath marginal basins and show how Precambrian crustal domains influenced basin evolution; (2) determine the deformation style of reactivated basement faults; and (3) assess the interplay between reactivated faults and the oceanic Romanche Fracture Zone. The combined geological and geophysical data show that reactivation of NE-SW to ENE-WSW continental-scale ductile shear zones that acted as crustal weakness zones started in the Early Cretaceous under a normal stress field. Stress field inversion occurred in the Barremian during the continental breakup when the South American plate started to became an independent intraplate area under a strike-slip stress regimes. The shear zones arrest at the E-W-striking Romanche Fracture Zone, which marks the continental-oceanic boundary. The major fault offsets occurred along the Transbrasiliano Shear Zone, which represented a collisional boundary between paleocontinents in the Neoproterozoic. Fault reactivation also occurred in the eastern boundary of the Ceará Terrace marginal ridge along the Transbrasiliano Shear Zone, uplifted during tectonic inversion. We conclude that fault reactivation mainly occurred between contrasting Precambrian terrains separated by ductile shear zones. Additionally, the folds associated with the Romanche Fracture Zone were mainly generated along reactivated faults that affected syn- to postrift units on the Equatorial Margin.

OriginalsprogEngelsk
Artikelnummer229446
TidsskriftTectonophysics
Vol/bind837
ISSN0040-1951
DOI
StatusUdgivet - aug. 2022

Bibliografisk note

Funding Information:
The authors thank Webster U. Mohriak, Philippe Schnürle, an anonymous reviewer, and Tectonophysics Editor Claire A. Currie for the valuable suggestions, which significantly improved this paper. We are grateful to the Brazilian oil and gas agency (Agência Nacional de Petróleo, Gás Natural e Biocombustíveis – ANP) for providing the geophysical data and Schlumberger for the Petrel software license. ACT thanks the Brazilian funding agency CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for her PhD grant and the International Ocean Drilling Program (IODP)/CAPES Geohazards and Tectonics Project (Nr. 88887.123925/2015–00), coordinated by Helenice Vital for support. We thank Rubson Maia for help in the conceptual model. ACT also acknowledges the Department of Geoscience, Aarhus University, for providing facilities during one year of her PhD in Denmark. DLC, FHRB, MPG, and HV thank the Brazilian Research Council (Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq) for their productivity grants.

Funding Information:
The authors thank Webster U. Mohriak, Philippe Schnürle, an anonymous reviewer, and Tectonophysics Editor Claire A. Currie for the valuable suggestions, which significantly improved this paper. We are grateful to the Brazilian oil and gas agency ( Agência Nacional de Petróleo, Gás Natural e Biocombustíveis – ANP ) for providing the geophysical data and Schlumberger for the Petrel software license. ACT thanks the Brazilian funding agency CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for her PhD grant and the International Ocean Drilling Program (IODP)/CAPES Geohazards and Tectonics Project (Nr. 88887.123925/2015–00), coordinated by Helenice Vital for support. We thank Rubson Maia for help in the conceptual model. ACT also acknowledges the Department of Geoscience, Aarhus University, for providing facilities during one year of her PhD in Denmark. DLC, FHRB, MPG, and HV thank the Brazilian Research Council ( Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq ) for their productivity grants.

Publisher Copyright:
© 2022 Elsevier B.V.

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