(particularly in the WAB) (Docherty and Banda 1992; Rodríguez-Fernández et al.
1999) and tectonics altered the sizes of the easterly sub-basins (Estrada et al. 1997;
Comas et al. 1999; Martínez-García et al. 2013). The uplift of the Alboran Ridge
propagated from NE to SW, splitting the EAB and WAB (Martínez-García et al.
2013). The Xauen and Tofiño banks area was extensively folded and uplifted
(Bourgois et al. 1992; Chalouan et al. 1997; d’Acremont et al. 2020; Lafosse et al.
2020) and, together with the Alboran Ridge, progressively led to the formation of a
long morphologic barrier in the late Pliocene that is presently ~130 km long and
1.75 km high (Ammar et al. 2007; Martínez-García et al. 2013; Vázquez et al. 2015).
The re-orientation of previous tectonic structures due to the changes in the stress
field during the Pliocene and Quaternary, along with the uplifting of diapirs in the
WAB (Pérez-Belzuz et al. 1997; Talukder et al. 2003), also conditioned smaller
morphotectonic changes behind other evolving tectonic features, such as basement
highs, structural scarps, mud volcanoes, and diapiric ridges.
The morphotectonically active setting that characterized the Alboran Sea during
the Pliocene and Quaternary involved a changing seafloor landscape and basin
configurations. They largely controlled the distribution and lateral continuity of the
Pliocene and Quaternary seismic stratigraphic units. The most common stratigraphic
boundaries of the overlying Pliocene and Quaternary stratigraphy were described in
Ryan et al. (1973) and Campillo et al. (1992), primarily along the Spanish margin. A
recent analysis identified the main tectonic/sedimentary reflectors in the SAB and
EAB (Martínez-García et al. 2013). All these sources were recently combined and
updated by Juan et al. (2016).
The Pliocene-Quaternary sequence of the Alboran Sea has been previously
addressed by means of industrial and academic wells (Jurado and Comas 1992;
Comas et al. 1999) and is known to consist of pelagic to hemipelagic marls and
shales (Fig. 5.11), interlayered with sandy turbidites and/or contourites (Alonso et al.
1999; Juan et al. 2020). Its base is marked by a discontinuity recognized across the
entire basin, linked to erosion and the Messinian Salinity Crisis (Estrada et al. 2011).
The overall geometric configuration of the Pliocene sequence and its units consists
of irregular subtabular sedimentary bodies and roughly wedge-shaped bodies
pinching out upslope and, locally, downslope (Juan et al. 2016). The Quaternary
sequence and its units primarily display wedge shapes along the Spanish and
Moroccan margins (Ercilla et al. 1994; Hernández-Molina et al. 2002), subtabular
shapes in the basin domains, and mounded shapes at the bases and walls of the
seamounts and escarpments, on the Alboran Ridge, and in the Alboran Trough (Juan
et al. 2016).
Throughout the Quaternary, sea level changes related to climate forcing
constrained the edification of continental shelf physiography, especially since the
middle Pleistocene, as a consequence of the greatest importance of the 100 k year
cycles (Hernández-Molina et al. 2002). In low sea level events, the continental shelf
is sculpted and grows seaward through the deposit of shelf-margin wedges tied to
continental sediment input from river mouths; in turn, high sea level events saw the
migration of the coast towards the continent and the deposit of coastal deltas and
138
J.-T. Vázquez et al.
1999) and tectonics altered the sizes of the easterly sub-basins (Estrada et al. 1997;
Comas et al. 1999; Martínez-García et al. 2013). The uplift of the Alboran Ridge
propagated from NE to SW, splitting the EAB and WAB (Martínez-García et al.
2013). The Xauen and Tofiño banks area was extensively folded and uplifted
(Bourgois et al. 1992; Chalouan et al. 1997; d’Acremont et al. 2020; Lafosse et al.
2020) and, together with the Alboran Ridge, progressively led to the formation of a
long morphologic barrier in the late Pliocene that is presently ~130 km long and
1.75 km high (Ammar et al. 2007; Martínez-García et al. 2013; Vázquez et al. 2015).
The re-orientation of previous tectonic structures due to the changes in the stress
field during the Pliocene and Quaternary, along with the uplifting of diapirs in the
WAB (Pérez-Belzuz et al. 1997; Talukder et al. 2003), also conditioned smaller
morphotectonic changes behind other evolving tectonic features, such as basement
highs, structural scarps, mud volcanoes, and diapiric ridges.
The morphotectonically active setting that characterized the Alboran Sea during
the Pliocene and Quaternary involved a changing seafloor landscape and basin
configurations. They largely controlled the distribution and lateral continuity of the
Pliocene and Quaternary seismic stratigraphic units. The most common stratigraphic
boundaries of the overlying Pliocene and Quaternary stratigraphy were described in
Ryan et al. (1973) and Campillo et al. (1992), primarily along the Spanish margin. A
recent analysis identified the main tectonic/sedimentary reflectors in the SAB and
EAB (Martínez-García et al. 2013). All these sources were recently combined and
updated by Juan et al. (2016).
The Pliocene-Quaternary sequence of the Alboran Sea has been previously
addressed by means of industrial and academic wells (Jurado and Comas 1992;
Comas et al. 1999) and is known to consist of pelagic to hemipelagic marls and
shales (Fig. 5.11), interlayered with sandy turbidites and/or contourites (Alonso et al.
1999; Juan et al. 2020). Its base is marked by a discontinuity recognized across the
entire basin, linked to erosion and the Messinian Salinity Crisis (Estrada et al. 2011).
The overall geometric configuration of the Pliocene sequence and its units consists
of irregular subtabular sedimentary bodies and roughly wedge-shaped bodies
pinching out upslope and, locally, downslope (Juan et al. 2016). The Quaternary
sequence and its units primarily display wedge shapes along the Spanish and
Moroccan margins (Ercilla et al. 1994; Hernández-Molina et al. 2002), subtabular
shapes in the basin domains, and mounded shapes at the bases and walls of the
seamounts and escarpments, on the Alboran Ridge, and in the Alboran Trough (Juan
et al. 2016).
Throughout the Quaternary, sea level changes related to climate forcing
constrained the edification of continental shelf physiography, especially since the
middle Pleistocene, as a consequence of the greatest importance of the 100 k year
cycles (Hernández-Molina et al. 2002). In low sea level events, the continental shelf
is sculpted and grows seaward through the deposit of shelf-margin wedges tied to
continental sediment input from river mouths; in turn, high sea level events saw the
migration of the coast towards the continent and the deposit of coastal deltas and
138
J.-T. Vázquez et al.