older sedimentary series, and the expansion and subsidence of the depocentres
demonstrate the intense tectonic activity of this period (Serrano et al. 2007).
The second generation of sedimentary basins formed under a top-to-the-WSW
extensional regime (Sanz de Galdeano and Vera 1992; Vera 2000; RodríguezFernández et al. 2011). These basins, defined as intramontane basins (e.g., Sorbas
Basin) are mostly located in the southeastern Betics and have similar stratigraphic
successions (Rodríguez-Fernández et al. 2011). Extensional structures observed at
the border of the basins or within the earlier deposits lead some authors to link their
initiation with the latest exhumation stages of the Nevado-Filábride complex
(Crespo-Blanc 1995; Meijninger and Vissers 2006; Rodríguez-Fernández and
Sanz de Galdeano 2006; Augier et al. 2013; Do Couto et al. 2014). In detail, the
asymmetrical distribution of the sedimentary series (e.g., Sorbas, Alpujarras corridor) combined with paleostress analysis show that numerous normal faults accommodated the subsidence of the basin.
Ongoing debates surround the amount of westward movement of the Alboran
Domain and its palaeogeographic origin (Jabaloy-Sánchez et al. 2019), the occurrence of STEP faults (Subduction-Transform-Edge-Propagator) (Mancilla et al.
2012, 2013, 2015; d’Acremont et al. 2020), the vergence of the subduction slab
and the direction of spreading in the Algerian oceanic basin (Fig. 5.5). In the Alboran
Region, recent geophysical measurements show that a remnant of relatively cold
lithosphere lies beneath the Gibraltar arc, under the subduction zone, displaying an
overall curved shape anomaly that reaches a depth of 600 km (Bezada et al. 2013).
The curvature of this anomaly roughly mimics the orogenic arc, hence its length
suggests the extent of the Tethys lithosphere slab retreat (Bezada et al. 2013).
5.3.3 Magmatism
The main positive reliefs on the Alboran seafloor are of igneous rocks. The late
Eocene—Pleistocene magmatism in the Alboran Domain is related to the collisional
orogenic processes resulting from Africa-Eurasia convergence (Duggen et al. 2004,
2008). A roughly 200 by 500 km NE–SW trending belt of middle Miocene to
Pleistocene volcanic rocks crops out in this region, which extends from southeastern
Spain through the central-eastern Alboran Sea into northeastern Morocco (Fig. 5.6).
The igneous activity took place in four main stages (Duggen et al. 2004, Gill et al.
2004; El Azzouzi et al. 2014) that are explained mostly in a context of an eastward
subduction and westward roll back of predominantly oceanic lithosphere model
(Lonergan and White 1997; Duggen et al. 2003). Nevertheless, there is still discussion about the mechanisms, convective removal of thickened lithosphere and delamination of the continental lithospheric mantle have also been proposed to explain in
part the magmatism (Platt et al. 1998; Duggen et al. 2005).
Stage 1 It corresponds to the intrusion of tholeiitic to calc-alkaline dyke swarms at
the Malaga area (Fig. 5.6) during the late Eocene to lower Miocene (Turner et al.
122
J.-T. Vázquez et al.
demonstrate the intense tectonic activity of this period (Serrano et al. 2007).
The second generation of sedimentary basins formed under a top-to-the-WSW
extensional regime (Sanz de Galdeano and Vera 1992; Vera 2000; RodríguezFernández et al. 2011). These basins, defined as intramontane basins (e.g., Sorbas
Basin) are mostly located in the southeastern Betics and have similar stratigraphic
successions (Rodríguez-Fernández et al. 2011). Extensional structures observed at
the border of the basins or within the earlier deposits lead some authors to link their
initiation with the latest exhumation stages of the Nevado-Filábride complex
(Crespo-Blanc 1995; Meijninger and Vissers 2006; Rodríguez-Fernández and
Sanz de Galdeano 2006; Augier et al. 2013; Do Couto et al. 2014). In detail, the
asymmetrical distribution of the sedimentary series (e.g., Sorbas, Alpujarras corridor) combined with paleostress analysis show that numerous normal faults accommodated the subsidence of the basin.
Ongoing debates surround the amount of westward movement of the Alboran
Domain and its palaeogeographic origin (Jabaloy-Sánchez et al. 2019), the occurrence of STEP faults (Subduction-Transform-Edge-Propagator) (Mancilla et al.
2012, 2013, 2015; d’Acremont et al. 2020), the vergence of the subduction slab
and the direction of spreading in the Algerian oceanic basin (Fig. 5.5). In the Alboran
Region, recent geophysical measurements show that a remnant of relatively cold
lithosphere lies beneath the Gibraltar arc, under the subduction zone, displaying an
overall curved shape anomaly that reaches a depth of 600 km (Bezada et al. 2013).
The curvature of this anomaly roughly mimics the orogenic arc, hence its length
suggests the extent of the Tethys lithosphere slab retreat (Bezada et al. 2013).
5.3.3 Magmatism
The main positive reliefs on the Alboran seafloor are of igneous rocks. The late
Eocene—Pleistocene magmatism in the Alboran Domain is related to the collisional
orogenic processes resulting from Africa-Eurasia convergence (Duggen et al. 2004,
2008). A roughly 200 by 500 km NE–SW trending belt of middle Miocene to
Pleistocene volcanic rocks crops out in this region, which extends from southeastern
Spain through the central-eastern Alboran Sea into northeastern Morocco (Fig. 5.6).
The igneous activity took place in four main stages (Duggen et al. 2004, Gill et al.
2004; El Azzouzi et al. 2014) that are explained mostly in a context of an eastward
subduction and westward roll back of predominantly oceanic lithosphere model
(Lonergan and White 1997; Duggen et al. 2003). Nevertheless, there is still discussion about the mechanisms, convective removal of thickened lithosphere and delamination of the continental lithospheric mantle have also been proposed to explain in
part the magmatism (Platt et al. 1998; Duggen et al. 2005).
Stage 1 It corresponds to the intrusion of tholeiitic to calc-alkaline dyke swarms at
the Malaga area (Fig. 5.6) during the late Eocene to lower Miocene (Turner et al.
122
J.-T. Vázquez et al.