Crustal deformation and submarine canyon incision in a Meso-Cenozoic first-order transfer zone (SW Iberia, North Atlantic Ocean)

• Published in: Tectonophysics
• Main Authors: Sousa Lemos Pereira, Ricardo Nuno, Alves, Tiago Marcos
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2013
• Subjects: GC Oceanography; Newfoundland; North Atlantic
• Online Access: https://orca.cardiff.ac.uk/id/eprint/48751/; https://doi.org/10.1016/j.tecto.2013.05.007

Using a dense grid of high-quality 2D seismic profiles, dredge and outcrop data, the offshore prolongation of a first-order transfer zone, the Messejana–Plasencia Fault Zone (MPFZ), is explained within the context of oblique rifting between Southwest Iberia, Newfoundland, and West Tethys. The offshore MPFZ is shown to comprise a 5–10 km wide region of deformation, oblique to the continental margin, reactivated in the Mesozoic as part of a wider transcurrent domain, the São Vicente sub-basin. Here, the geometry of faults and strata denotes the generation of a pull-apart basin during the Jurassic-Early Cretaceous. In contrast, its Late Cretaceous to Cenozoic evolution favours left-lateral transpression during the counter-clockwise rotation and eastward migration of Iberia towards its present position. Erosion was subsequently enhanced in the São Vicente sub-basin due to the reactivation of syn-rift structures. By documenting the evolution of the São Vicente sub-basin, and adjacent MPFZ, this work demonstrates: 1) the temporal and spatial scales in which first-order transfer zones accommodate crustal movements during continental rifting and subsequent inversion episodes; 2) the generation of an extensive region of strain accommodation in the vicinity of the MPFZ, an observation with profound implications to future palaeogeographic reconstructions of the North Atlantic Ocean; and 3) that the São Vicente Canyon, the physiographic expression of the MPFZ, incised the margin as early as the latest Cretaceous-Paleocene, synchronously with the onset of tectonic uplift in Southwest Iberia. In such a setting, the São Vicente sub-basin and MPFZ formed important by-pass corridors for sediment sourced from proximal areas of the margin. At present, the MPFZ comprises a complex releasing-restraining bend accommodating important vertical and horizontal movements in Southwest Iberia. Based on earthquake data from similar transfer zones, the MPFZ should be able to generate large-magnitude earthquakes and potentially destructive ...