opening the Algero-Provencal basin as the main oceanic back-arc basin along the
Miocene (20–10 Ma) between the Balearic Islands, Tell, Corsica, and Sardinia.
The Alboran Sea, most of the Tyrrhenian Sea (between the Apennines and
Corsica-Sardinia block), and the Valencia Trough, developed by the clockwise
rotation of the Balearic Promontory with respect to Iberia, constitute the main
sedimentary basins formed on strongly stretched thinned continental crust. Moreover, small areas of the Tyrrhenian Sea are floored by Pliocene-Quaternary oceanic
crust. The absence of clear seafloor linear magnetic anomalies (Galdeano and
Rossignol 1977) impedes a detailed study of the oceanic spreading.
Deformation continues up to the consumption of the Ligurian Tethys oceanic
lithosphere (Fig. 5.2) and collision of the accretionary prisms with the forelands that
represent the main alpine belts surrounding the Western Mediterranean (Jolivet and
Faccenna 2000; Handy et al. 2010). In this context, the Alboran Sea is generated in
the interior of the Betic-Rif orocline by extensional forces linked to the contraction
resulting from African-Eurasian convergence, which continues up to Present, with
the coetaneous retreating of an eastward-dipping slab below the Gibraltar Arc
(Pedrera et al. 2011; Faccenna et al. 2014; Molina-Aguilera et al. 2019).
5.3.2 Evolutive Models
In the literature, no consensus exists regarding the tectonic evolution, however, the
scientific community agrees that a major change occurred in the subduction regime
during the Oligocene (Faccenna et al. 1997; Jolivet and Faccenna 2000). In the
Western Mediterranean basin, several hypotheses approach the lithosphere dynamics. They could be synthesized in (1) double westward (Gibraltar Arc) and eastward
(Calabrian Arc) slab retreat, (2) slab fragmentation, and (3) continental delamination. These models have been proposed to explain the formation of forearc and backarc basins, involving the extension, exhumation of metamorphic core units in
internal zones and collapse of orogens (Royden 1993; Lonergan and White 1997;
Jolivet and Faccenna 2000; Wortel and Spakman 2000; Faccenna et al. 2004;
Spakman and Wortel 2004; Handy et al. 2010). In response to slab retreats, several
back-arc basins have opened in the Western Mediterranean region: the LiguroProvençal basin, Algerian basin, Alboran Sea, and the Tyrrhenian Sea, among others
(Faccenna et al. 2001).
The Alboran Sea remains one of the most controversial issues in Western
Mediterranean geodynamics. The present-day complex geometry of seismic tomography anomalies in the mantle show clear evidence of subducted remnants resulting
from progressive slab tearing and detachment (Carminati et al. 1998a, b; Wortel and
Spakman 2000; Bezada et al. 2013; Spakman et al. 2018; Molina-Aguilera et al.
2019) associated with a complex mantle convection pattern (Faccenna et al. 2004;
Spakman and Wortel 2004; Jolivet et al. 2009; Faccenna and Becker 2010; Sternai
et al. 2014). Nevertheless, the exact nature of subducted material remains unclear,
5 A Geological History for the Alboran Sea Region
119
Miocene (20–10 Ma) between the Balearic Islands, Tell, Corsica, and Sardinia.
The Alboran Sea, most of the Tyrrhenian Sea (between the Apennines and
Corsica-Sardinia block), and the Valencia Trough, developed by the clockwise
rotation of the Balearic Promontory with respect to Iberia, constitute the main
sedimentary basins formed on strongly stretched thinned continental crust. Moreover, small areas of the Tyrrhenian Sea are floored by Pliocene-Quaternary oceanic
crust. The absence of clear seafloor linear magnetic anomalies (Galdeano and
Rossignol 1977) impedes a detailed study of the oceanic spreading.
Deformation continues up to the consumption of the Ligurian Tethys oceanic
lithosphere (Fig. 5.2) and collision of the accretionary prisms with the forelands that
represent the main alpine belts surrounding the Western Mediterranean (Jolivet and
Faccenna 2000; Handy et al. 2010). In this context, the Alboran Sea is generated in
the interior of the Betic-Rif orocline by extensional forces linked to the contraction
resulting from African-Eurasian convergence, which continues up to Present, with
the coetaneous retreating of an eastward-dipping slab below the Gibraltar Arc
(Pedrera et al. 2011; Faccenna et al. 2014; Molina-Aguilera et al. 2019).
5.3.2 Evolutive Models
In the literature, no consensus exists regarding the tectonic evolution, however, the
scientific community agrees that a major change occurred in the subduction regime
during the Oligocene (Faccenna et al. 1997; Jolivet and Faccenna 2000). In the
Western Mediterranean basin, several hypotheses approach the lithosphere dynamics. They could be synthesized in (1) double westward (Gibraltar Arc) and eastward
(Calabrian Arc) slab retreat, (2) slab fragmentation, and (3) continental delamination. These models have been proposed to explain the formation of forearc and backarc basins, involving the extension, exhumation of metamorphic core units in
internal zones and collapse of orogens (Royden 1993; Lonergan and White 1997;
Jolivet and Faccenna 2000; Wortel and Spakman 2000; Faccenna et al. 2004;
Spakman and Wortel 2004; Handy et al. 2010). In response to slab retreats, several
back-arc basins have opened in the Western Mediterranean region: the LiguroProvençal basin, Algerian basin, Alboran Sea, and the Tyrrhenian Sea, among others
(Faccenna et al. 2001).
The Alboran Sea remains one of the most controversial issues in Western
Mediterranean geodynamics. The present-day complex geometry of seismic tomography anomalies in the mantle show clear evidence of subducted remnants resulting
from progressive slab tearing and detachment (Carminati et al. 1998a, b; Wortel and
Spakman 2000; Bezada et al. 2013; Spakman et al. 2018; Molina-Aguilera et al.
2019) associated with a complex mantle convection pattern (Faccenna et al. 2004;
Spakman and Wortel 2004; Jolivet et al. 2009; Faccenna and Becker 2010; Sternai
et al. 2014). Nevertheless, the exact nature of subducted material remains unclear,
5 A Geological History for the Alboran Sea Region
119