The influence of shelf-indenting canyons and infralittoral prograding wedges on coastal morphology: The Carchuna system in Southern Spain

Ortega-Sánchez, Miguel; Lobo, F. J.; López‐Ruiz, Alejandro; Losada, Miguel Á.; Fernández-Salas, L.M.

doi:10.1016/j.margeo.2013.11.006

Cited by 33 publications

(14 citation statements)

References 52 publications

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“…These large‐scale shoreline undulations may be forced by inlets, by islands, by offshore bathymetric anomalies, etc. [ Bender and Dean , ; McNinch , ; Valvo et al , ; Ortega‐Sánchez et al , ]. However, we here deal with those that are not forced externally but that are instead generated by positive feedbacks between waves and morphology through sediment transport.…”

Section: Introductionmentioning

confidence: 99%

Formation mechanisms for self‐organized kilometer‐scale shoreline sand waves

et al. 2017

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The feedbacks between morphology and waves through sediment transport are investigated as a source of kilometer‐scale shoreline sand waves. In particular, the observed sand waves along Srd. Holmslands Tange, Denmark, are examined. We use a linear stability model based on the one‐line approximation, linking the bathymetry to the perturbed shoreline. Previous models that consider the link by shifting the equilibrium profile and neglecting the curvature of the depth contours predict a positive feedback only if the offshore wave incidence angle (θc) is above a threshold, θc≃42°. Considering curvilinear depth contours and using a linearly decaying perturbation in bed level, we find that θc can vary over the range 0–90° depending on the background bathymetric profile and the depth of closure, Dc. Associated to the perturbed wave refraction, there are two sources of instability: the alongshore gradients in wave angle, wave angle mechanism, and the alongshore gradients in wave energy induced by wave crest stretching, wave energy mechanism. The latter are usually destabilizing, but the former are destabilizing only for large enough Dc, steep foreshores, and gently sloping shorefaces. The critical angle comes out from the competition between both mechanisms, but when both are destabilizing, θc=0. In contrast with earlier studies, the model predicts instability for the Holmslands Tange coast so that the observed sand waves could have emerged from such instability. The key point is considering a larger Dc that is reasonably supported by both observations and wave climate, which brings the wave angle mechanism near the destabilizing threshold.

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Section: Introductionmentioning

confidence: 99%

Formation mechanisms for self‐organized kilometer‐scale shoreline sand waves

et al. 2017

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“…Sheet-like deposits may be found intercalated between the regressive wedges ( Figure 11). The most recent depositional event is recorded by inner shelf wedges off the main entry points [13,50], evolving into sigmoid-to-oblique in places of minor fluvial inputs [51,52]. The thickness of major regressive wedges can be 50 ms TWTT or slightly higher on the shelf, and they usually exhibit forestepping stacking patterns [13,53]; the progradation distances generated by such stacking patterns is usually moderate (i.e., few kilometers) ( Figure 11, Table 2).…”

Section: The Southern Shelf Sectormentioning

confidence: 99%

“…The type of sediment input is markedly torrential, with numerous but seasonal minor rivers (e.g., Guadalhorce, Guadalfeo, Adra) and creeks that produce violent, flash floods. In addition, the prevailing uplifting along the Betic Cordillera led to the occurrence of abrupt margins that together with frequent submarine canyons would lead to the generation of such undersupplied margins, as hyperpycnal flows and littoral dynamics could be captured by canyons [52,73] and contribute to submarine fan formation [72].…”

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confidence: 99%

Variability of Shelf Growth Patterns along the Iberian Mediterranean Margin: Sediment Supply and Tectonic Influences

et al. 2018

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Clinoform depositional features along the Iberian Mediterranean margin are investigated in this study, with the aim of establishing the causes of their varied shapes and other characteristics. We have analyzed the broad-scale margin physiography and seismic stratigraphic patterns based on high-resolution bathymetric data and previously interpreted seismic data. In addition, we have evaluated regional supply conditions and the uplift-subsidence regime of the different shelf sectors. The upper Quaternary record is strongly dominated by shelf-margin regressive wedges affected by the prevailing 100 ka cyclicity. However, the margins exhibit considerable lateral variability, as the result of the balance between the amount of sediment supply and the uplift-subsidence relationship. Three major shelf sectors with distinct morpho-sedimentary features have been defined. The relatively narrow northern shelves (Roses, La Planassa and Barcelona) are supplied by discrete river outlets that collectively constitute a linear source and are mainly affected by tectonic tilting. The wide middle shelves (Ebro Shelf, the Gulf of Valencia, and the Northern Arc) receive the sediment supply from the large Ebro River and other medium rivers. Although the tectonic regime changes laterally (strong subsidence in the north and uplift in the south), shelf growth is maintained by lateral advection of sediments. The southern shelves (the Southern Arc and the northern Alboran Shelf) are very abrupt and narrow because of the uplifting Betic Cordillera, and the torrential fluvial regimes that determine a very efficient sediment by-pass toward the deep basin. Submarine canyons deeply incised in the continental margin constitute a key physiographic feature that may enhance the transport of sediment to the deep sea or individualize shelf sectors with specific sedimentation patterns, as occurs in the Catalan margin.

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“…Carchuna Beach, in the province of Granada (SE Spain, Figure 1), has been one of the outcrops on which studies of these progradational units of the coastal plain have focused [9,[12][13][14][15][16]. This beach is 4 km long and is bordered to the west by Cape Sacratif and to the east by the tip of Cerro Gordo (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Ground-Penetrating Radar Study of Progradational Units in Holocene Coastal Plains: Carchuna Beach (SE Spain)

et al. 2020

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The internal geometries of progradational units on the coastal plain in southeastern Spain (Carchuna Beach, Granada) since the maximum Holocene marine transgression (ca. 7000 cal BP) have been analysed using ground-penetrating radar (GPR). Radargram analysis shows the presence of sedimentary structures consistent with the progradation of coastal plains, interpreted as laminations associated with the foreset and topset. Laterally, five middle scale progradational units (H2, H3, H4, H5 and H6) are identified. Each of these units can be grouped into two major units. The general trend towards progradation is interrupted at the boundary of the units. Minor scale units (prograding wedges), deposited at topographically lower areas, are detected in GPR profiles. The radargrams also show channel erosional surfaces and sigmoidal landward dipping reflections interpreted as washover channel deposits, with the erosion and transference of sediments between the beach and the back-ridge domain. Furthermore, the saturation of coastline sediments with saltwater rapidly attenuates the GPR signal. Thus, the GPR is also a good tool to detect saltwater intrusions in shallow aquifers.

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The influence of shelf-indenting canyons and infralittoral prograding wedges on coastal morphology: The Carchuna system in Southern Spain

Cited by 33 publications

References 52 publications

Formation mechanisms for self‐organized kilometer‐scale shoreline sand waves

Formation mechanisms for self‐organized kilometer‐scale shoreline sand waves

Variability of Shelf Growth Patterns along the Iberian Mediterranean Margin: Sediment Supply and Tectonic Influences

Ground-Penetrating Radar Study of Progradational Units in Holocene Coastal Plains: Carchuna Beach (SE Spain)

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