Evidence of Segmentation in the Iberia–Africa Plate Boundary: A Jurassic Heritage?

Abstract

The present structure of the Iberia–Africa plate boundary between the Gorringe Bank and the Algerian Basin is characterized by a highly segmented geometry and diffused seismicity. Filtered Bouguer gravity data show conspicuous highs coinciding with the Gorringe Bank, the Guadalquivir–Portimao Bank, and the Ronda/Beni–Bousera massifs, reflecting the current geometry of the plate boundary segments. The Africa–Eurasia Alpine convergence produced crustal-scale thrusting in the Atlantic segments and roll-back subduction in the Ligurian–Tethys segments. Despite the growing consensus that the Gorringe and the Guadalquivir–Portimao Banks resulted from tectonic inversion of hyperextended margin structures inherited from the Early Jurassic, this heritage is more debatable for the Ronda/Beni–Bousera massifs lacking models linking the Atlantic and Mediterranean realms. On the basis of gravity analysis combined with plate reconstruction models, geological cross-sections, and recent local tomography, we infer a strong Jurassic heritage of the present-day segmentation and substantiate a comprehensive tectonic evolution model of the Iberia–Africa plate boundary since the Early Jurassic to Recent that includes the Atlantic and the Mediterranean domains.

Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

“…The palaeo-thermal structure in the HT-metamorphism zone in the Nieves Unit showing an obliquity of isograds with the contact also reinforces our extensional emplacement model. The proposed extensional setting with mantle exhumation fits the observations of Pedrera et al (2020) with sheared peridotite bodies embedded in Triassic sediments and is similar to what is generally expected from the pre-orogenic setting of the Betics corresponding to a former oblique and segmented system between the Central Atlantic and the Western Tethys (Leprêtre et al, 2018;Fernàndez et al, 2019;Angrand et al, 2020;Pedrera et al, 2020).…”

“…Proposed ages range from the early Permian (Rossetti et al, 2020;Acosta-Vigil et al, 2014) to the Jurassic (Michard et al, 1991;Sanchez-Rodriguez et al, 1996), the Late Oligocene or Early Miocene (Précigout et al, 2013;Frasca et al, 2017;Gueydan et al, 2019). Recent models also propose a Mesozoic hyperextension and mantle exhumation within the segmented rift system between Iberia and Africa (Fernàndez et al, 2019;Pedrera et al, 2020). The main reason for this lack of consensus is the clustering of most radiometric ages at ca.…”

A kinematic reconstruction of Iberia using intracontinental strike‐slip corridors

“…Similarly, the reconstructed Jurassic IB‐AFR motion path is parallel to displacement zones inferred by Fernández et al. (2019). Both structural trends fit with the motion path and confirm the validity of our approach (Figure 1).…”

Opposite Symmetry in the Lithospheric Structure of the Alboran and Algerian Basins and Their Margins (Western Mediterranean): Geodynamic Implications

“…The opposite direction of slab retreat in the adjacent segments proposed by scenario 3 (Figure 1b and Vergés & Fernàndez, 2012) implies opposite symmetry in the crust and upper mantle structure as observed in our models (Figure 8). Scenario 3 is based on the pre‐convergence geometry of the Iberia‐Africa Ligurian‐Tethys, characterized by markedly segmented margin configuration (Fernàndez et al., 2019; Frizon de Lamotte et al., 2011; Martín‐Chivelet et al., 2019; Pedrera et al., 2020; Ramos et al., 2020; Schettino & Turco, 2011; Vergés & Fernàndez, 2012). The margin segmentation exerted a strong control on the further evolution of the Ligurian‐Tethys realm allowing for opposed subduction polarities in adjacent segments.…”

“…The Ligurian‐Tethys rifting and subsequent ocean spreading started during Early‐Middle Jurassic by the propagation of the Central Atlantic ridge separating Africa, Iberia, and Adria. The Ligurian‐Tethys transtensive rifting resulted in a highly extended and segmented Iberian and Africa margins transitioning to oceanic lithosphere to the east (Angrand et al., 2020; Fernàndez et al., 2019; Frizon de Lamotte et al., 2011; Schettino & Turco, 2011; Stampfli & Borel, 2002; Vergés & Fernàndez, 2012). The protracted N‐NNW displacement of Africa relative to Eurasia since late Santonian was accommodated by the consumption of the Ligurian‐Tethys oceanic domain.…”