Influence of Precambrian shear zones on the formation of oceanic fracture zones along the continental margin of Brazil

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  • David L. Vasconcelos, Universidade Federal do Rio Grande do Norte, Brazil
  • Francisco H.R. Bezerra, Universidade Federal do Rio Grande do Norte, Brazil
  • Ole Rønø Clausen
  • Walter E. Medeiros, Universidade Federal do Rio Grande do Norte, Brazil
  • David L. de Castro, Universidade Federal do Rio Grande do Norte, Brazil
  • Helenice Vital, Universidade Federal do Rio Grande do Norte, Brazil
  • José A. Barbosa, Universidade Federal de Pernambuco, Recife, Brazil

Structural inheritance control of oceanic fracture zone formation by a large basement shear zone during continental breakup is still a matter of debate. In this research, we investigated the reactivation of Precambrian shear zones and their role in the formation of the Ascension and Fernando Poo fracture zones during the evolution of the South Atlantic Ocean. We used aeromagnetic and multichannel 2D seismic reflection data associated with previous geological and geophysical data to analyze how the Precambrian shear zones may have influenced the formation of oceanic fracture zones. Our results suggest that the fracture zones are extensions of the shear zones in the transition between continental and oceanic crust. The São Miguel do Aleixo and Pernambuco shear zones were reactivated during the Pangea breakup and acted as zones of weakness controlling the location of the Ascension and Fernando Poo fracture zones during the process of oceanic crust spreading. Our model suggests that the formation of these fracture zones influenced by the shear zones occurred in the early stages of ocean opening. It indicates that the fracture zones that formed in the late opening stages were related to the thermal subsidence stage, as suggested in previous studies.

Original languageEnglish
JournalMarine and Petroleum Geology
Volume101
Pages (from-to)322-333
Number of pages12
ISSN0264-8172
DOIs
Publication statusPublished - Mar 2019

    Research areas

  • Ascencion fracture zone, Continental breakup, Fernando Poo fracture zone, Oceanic fracture zone, Shear zone, Structural inheritance

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