geomorphological types can be classified according to their genesis in depositional,
erosive, gravitational, and anthropogenic origins (Bárcenas et al. 2016).
6.5.1.1 Depositional Features
The most important types are prodeltaic wedges and infralittoral prograding wedges
(IPWs). Additionally, bedform fields at various scales have been documented in
specific locations (Fig. 6.4).
Prodeltaic bodies are wedge-shaped morphologies with variable seaward extensions, depending on the dimensions of the parent drainage basins (Fig. 6.4a, b, c).
They exhibit very narrow topsets (relatively flat proximal segments) bounded seawards by a shallow break of slope, close to the coast. Seawards, the seafloor gradient
is higher in the foresets and becomes distally asymptotic in the bottomsets. These
geomorphological boundaries are controlled by the wave base levels associated to
medium and high-energy conditions (Bárcenas et al. 2015). Overall, the vast majority of cross-sectional geometries are concave-upward (Fig. 6.4c, d). In plain view,
these dominant geometries mostly produce lobate and elongate patterns (Bárcenas
et al. 2015). The seismic facies of prodeltaic bodies are mainly stratified with
progradational and aggradational patterns. The progradational pattern is
characterised by an oblique-sigmoidal configuration and varies from perpendicular
to oblique to parallel with respect to the shoreline (Lobo et al. 2014). Most of the
prodeltaic wedges of the Alboran Sea exhibit superimposed seafloor undulations
over the foresets and bottomsets (Fig. 6.4a, b, c, d). The undulations can be up to a
few metres high and the wavelengths range between tens and hundreds of metres
(Bárcenas et al. 2009; Lafosse et al. 2018). These undulations are generally regarded
as sediment waves (Fernández-Salas et al. 2007).
Infralittoral prograding wedges (IPWs) are narrow (i.e. a few kilometres wide)
wedge-shaped clinoform bodies which have been mapped in the inner shelf stretches
of the Iberian margin (Fig. 6.4c, e). A well-marked break of slope occurs at water
depths of about 20–25 m; seawards, a steep slope of greater than 2
extends to water
depths of up to 60 m (Hernández-Molina et al. 2000). The characteristic slope break
may be relatively linear and continuous or instead be composed of arcuate, discontinuous segments (Fernández-Salas et al. 2009). These wedges have been recognised
in several sectors, but the most important bodies occur off Carchuna-Calahonda,
Campo de Dalías, and Gata Cape (Hernández-Molina et al. 2000; Fernández-Salas
et al. 2009). In some particular cases, such as off the Adra River the infralittoral
wedges develop laterally from the main deltaic protuberances, representing the
morphological response of an evolving deltaic system (Jabaloy-Sánchez et al.
2010) (Fig. 6.4c). In the Carchuna-Calahonda shelf area (Iberian shelf) and the
Nekor Basin shelf (African shelf), marine-built terraces observed at different water
depths from the outer to the inner shelf, are regarded as the morphological expression of IPWs (Martínez-Martos et al. 2016; Lafosse et al. 2018).
Fields of large-scale bedforms such as elongated bars and ridges have been
described in specific outer shelf settings of the Iberian shelf (Lobo et al. 2006;
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G. Ercilla et al.
erosive, gravitational, and anthropogenic origins (Bárcenas et al. 2016).
6.5.1.1 Depositional Features
The most important types are prodeltaic wedges and infralittoral prograding wedges
(IPWs). Additionally, bedform fields at various scales have been documented in
specific locations (Fig. 6.4).
Prodeltaic bodies are wedge-shaped morphologies with variable seaward extensions, depending on the dimensions of the parent drainage basins (Fig. 6.4a, b, c).
They exhibit very narrow topsets (relatively flat proximal segments) bounded seawards by a shallow break of slope, close to the coast. Seawards, the seafloor gradient
is higher in the foresets and becomes distally asymptotic in the bottomsets. These
geomorphological boundaries are controlled by the wave base levels associated to
medium and high-energy conditions (Bárcenas et al. 2015). Overall, the vast majority of cross-sectional geometries are concave-upward (Fig. 6.4c, d). In plain view,
these dominant geometries mostly produce lobate and elongate patterns (Bárcenas
et al. 2015). The seismic facies of prodeltaic bodies are mainly stratified with
progradational and aggradational patterns. The progradational pattern is
characterised by an oblique-sigmoidal configuration and varies from perpendicular
to oblique to parallel with respect to the shoreline (Lobo et al. 2014). Most of the
prodeltaic wedges of the Alboran Sea exhibit superimposed seafloor undulations
over the foresets and bottomsets (Fig. 6.4a, b, c, d). The undulations can be up to a
few metres high and the wavelengths range between tens and hundreds of metres
(Bárcenas et al. 2009; Lafosse et al. 2018). These undulations are generally regarded
as sediment waves (Fernández-Salas et al. 2007).
Infralittoral prograding wedges (IPWs) are narrow (i.e. a few kilometres wide)
wedge-shaped clinoform bodies which have been mapped in the inner shelf stretches
of the Iberian margin (Fig. 6.4c, e). A well-marked break of slope occurs at water
depths of about 20–25 m; seawards, a steep slope of greater than 2
extends to water
depths of up to 60 m (Hernández-Molina et al. 2000). The characteristic slope break
may be relatively linear and continuous or instead be composed of arcuate, discontinuous segments (Fernández-Salas et al. 2009). These wedges have been recognised
in several sectors, but the most important bodies occur off Carchuna-Calahonda,
Campo de Dalías, and Gata Cape (Hernández-Molina et al. 2000; Fernández-Salas
et al. 2009). In some particular cases, such as off the Adra River the infralittoral
wedges develop laterally from the main deltaic protuberances, representing the
morphological response of an evolving deltaic system (Jabaloy-Sánchez et al.
2010) (Fig. 6.4c). In the Carchuna-Calahonda shelf area (Iberian shelf) and the
Nekor Basin shelf (African shelf), marine-built terraces observed at different water
depths from the outer to the inner shelf, are regarded as the morphological expression of IPWs (Martínez-Martos et al. 2016; Lafosse et al. 2018).
Fields of large-scale bedforms such as elongated bars and ridges have been
described in specific outer shelf settings of the Iberian shelf (Lobo et al. 2006;
166
G. Ercilla et al.