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Shaded relief map of the Albora´nAlbora´n Basin compiled from multibeam data. See Fig. 2 for names of prominent topographic features. AI ¼ Albora´nAlbora´n Island; AL ¼ Almun˜ecarAlmun˜ecar Canyon System; AM ¼ Almerıá Canyon System; C ¼ Calahonda Canyon System ; F ¼ Fuengirola Canyon System; D ¼ Dalıás Canyon System; M ¼ Motril Canyon System; SC ¼ Serrata-Carboneras Fault.
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Bathymetric, 3D relief and shaded relief maps created from multibeam echo-sounding data image the morphology of the Alborán Basin, a structural low along the east–west-trending Eurasian–African plates boundary. Topographic features in the basin are the consequence of volcanism associated with Miocene rifting, rift and post-rift sedimentation, and r...
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... southeast to east of south-plunging swell extending from the shelf's edge to a depth of 850 m; Chella Bank is located east of the axis of this swell (Fig. 2). Along the west side of this swell is a chain of narrow depressions that terminate northward on a line of northwest-trending ridges that in turn terminate about a northeast-aligned fracture (Fig. 3). In its center is another north-trending swell whose outer edge is about 900 m deep. West of the embayment is a northwest to southeast-trending swell at whose southeastern end is the Algarrobo Seamount. This swell marks the location of Malaga sub-basin (Fig. 2). The Albora´nAlbora´n Basin north apron from slightly east of 3150 0 W to ...
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... scarp and the ridge itself terminate on the Habibas Escarpment. Along the southeast scarp are 2 km-wide benches, one located at 3115 0 W and the other at 3107 0 W. At the base of the scarp also are presnt two irregular surfaced terrains, one near 31W and the other at 3110 0 W, with the latter extending to the crest of the Albora´nAlbora´n Ridge (Fig. 3). Onlapping the southeast side of the Albora´nAlbora´n Ridge also are three fans, one east of 3115 0 W, another near 3100 0 W and the third at 2154 0 W. Feeding the last one is a canyon that can be traced to the edge of the platform at the crest of the Albora´nAlbora´n Ridge. The fan at 3100 0 W also is fed by a single canyon displaying ...
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... biotherms probably composed of deep-water corals. Apparently, deep-water corals tend to concentrate in regions of tectonic uplift, such as the highs in the Albora´nAlbora´n Basin ( Hoernle et al., 2003). Many of the seamounts are partially surrounded by circular outlined moats that seismic reflection profiles (Alonso and Maldonado, 1992; their Fig. 3) show are erosional in origin; they are probably due to bottom current activity. The multibeam data recorded during the present investigation verify such an ...
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... canyons and channels in the Albora´nAlbora´n Basin are found on the basin's north slope, the east side of Djibouti Trough and the flanks of the Albora´nAlbora´n Trough and Ridge and Habibas Escarpment (Fig. 3). The canyons on the basin's north slope, west of Cabo de Gata, extend some distance onto the basin's apron before dying out, whereas the erosional features on the east side of the Djibouti Trough, Albora´nAlbora´n Ridge and Trough and Habibas Escarpment are generally limited to the scarps. In those along the southeast side of the ...
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... have grouped the submarine canyons on the basin's north slope into five systems: the Fuengirola ( Ercilla et al., 1992), Almun˜ecarAlmun˜ecar, Motril, Calahonda, Campo de Dalıás and Almerıá canyon systems (Fig. 3). According to Alonso and Ercilla (2003), the rivers feeding many of these systems are of similar length, 69-96 km, and drain areas of about the same size of 1258-1915 km 2 . The Fuengirola system on the west drains into the West Albora´nAlbora´n sub-basin, the Almun˜ecarAlmun˜ecar, Motril and Calahonda systems into the Djibouti Trough ...
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... of these systems are of similar length, 69-96 km, and drain areas of about the same size of 1258-1915 km 2 . The Fuengirola system on the west drains into the West Albora´nAlbora´n sub-basin, the Almun˜ecarAlmun˜ecar, Motril and Calahonda systems into the Djibouti Trough and those in the Gulf of Almerıá into the East Albora´nAlbora´n sub-basin (Fig. ...
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... Fuengirola System, supposedly fed now or in the past by Rıó de Fungirola, displays a simple geometry consisting of a meandering trunk valley that cuts into the shelf's edge and can be traced to a depth of 1100 m (Fig. 3). The main canyon is sinuous and has a length of about 33 km and a relief ranging from about 100 m at its head to less than 10 m at its mouth. A distributary splaying from the main channel at 36120 0 N has topographic expression to a depth of about 950 ...
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... East slope of the Djibouti Trough and south side of the 36110 0 N high A system of northwest-trending 9-20 km long, o1 to 1 km wide and tens of meters deep gullies occur on the east slope of the Djibouti Trough and on the south side of the 36110 0 N high (Figs. 3-5). Their topographic continuity is disrupted by one circular depression that probably represents a pockmark formed by the expulsion of gas (see below). The southeast of the Serrata-Carboneras Fault extends to the base of the slope descending to the East Albora´nAlbora´n Sub-Basin. Those in the 36110 0 N high are connected to the ...
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... shaded relief map in Fig. 3 and the 3-D map in Fig. 11 allow one to appreciate the nature and extent of linear topographic features on the Albora´nAlbora´n Basin. These features, which are limited to the part of the Albora´nAlbora´n Basin east of 3140 0 W, have three topographic expressions, scarps, narrow linear furrows and ridges and a chain of small ...
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... infer that all these features are the expressions of faulting and folding, and as these dislocations affect the sea floor, they are of recent geologic age. The faults display four trends: east-west, northeast-southwest and west of north and northwest, and affect the sea floor, indicating that they are active or have been active in the recent past (Fig. 3). In a companion paper ( Ballesteros et al., in press), we discuss the significance and origin of these ...
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... Masswasting structures associated with volcanic structures and B/O Vizconde de Eza, a metamorphic basement high, range from embayments created by slumping/debris flows to irregular topography. We infer that the irregular topography on the northwest side of the Albora´nAlbora´n Ridge between 2140 0 W and 310 0 W was formed by creep or thin slides (Fig. 3). Embayments along the bases and upper slope of seamounts formed by gravitational processes range in size from 2 Â 2 km to features whose dimensions are in the order of tens of km. ...
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A detailed study of the relationships between basements and lava flows gives the full meaning of the modifications due to the volcanic environment. Syneffusive thermal metamorphism is an exceptional event and posteffusive evolution of fossilized profiles consists of weak but typical chemical and mineralogical contaminations. This cryptoevolution is...
Citations
... In a very different context, other authors interpret some kilometric diapirs located in a tectonically inactive basin in northern Calabria [28]. However, they attribute a similar genesis to many other mud diapirs from volcanic provinces of the Mediterranean with active tectonics [31][32][33]. ...
The mouth of the Tinto River is located on the southwest coast of the Iberian Peninsula in the northwest of the Gulf of Cadiz. The river flows into an estuarine system shared with the Odiel River, commonly known as the “Ría de Huelva”. In the 1960s, a wide area of ancient salt marshes was transformed by a stockpile of industrial wastes of phosphogypsum, reaching a height of 35 m above the level of the salt marsh at its highest point. Two surveys using high-resolution seismic reflection in conjunction with a parametric profiler were carried out in 2016 and 2018. The purpose of these geophysical studies was the realization of a 3D model of the sedimentary units constituting the most recent filling of the estuary. The records present abundant extrusion structures located on the margins of the waste stockpiles, which break the visible stratification of the surficial units of the estuary. In some sectors, these structures have reached the estuarine surface and have, therefore, a morphological expression on the estuarine floor. The origin of these structures is interpreted as a vertical escape of fluidized sediments from lower units caused by overpressure from stacking.
... soft bottoms, rocky outcrops and cliffs), as well as in the circalittoral and bathyal zones (e.g. submarine canyons, banks, knolls, carbonated mounds and mud volcanoes) (Muñoz et al. 2008, Palomino et al. 2015Vázquez et al. 2021). This also promotes a great heterogeneity of benthic habitats and communities that favour the presence of species with different ecological requirements, including some that are highly threatened and vulnerable (Templado 2011, Templado et al. 2021, Rueda et al. 2021. ...
... Other small elevations or pinnacles with steeper slopes are located around the NE and W slopes between 135 and 200 m depth (Muñoz et al. 2008). These areas are dominated by rocky outcrops colonized by communities of large sponges (e.g. ...
Molluscs of Chella Bank and its surroundings were studied from 21 samples collected with a van Veen grab in the depth range 95-729 m. A total of 299 taxa were identified (77 live-taken), thus increasing by more than 95% the species of molluscs reported in the recently declared site of community importance “Sur de Almería–Seco de los Olivos”. Two of the species are new records to Spanish waters and one to the Alboran Sea. The high species richness observed could be related to the location, the hydrological characteristics and the topographical heterogeneity of the area within the Alboran Sea. Four significant groups of samples were discriminated through multivariate analysis of quantitative data of live-taken molluscs: (I) bathyal muddy bottoms with buried rhodoliths; (II) bathyal muddy bottoms with coral rubble; (III) bathyal hemipelagic muddy bottoms and (IV) bathyal sandy bottoms. Molluscs were more diverse on coral framework bottoms than on sedimentary bottoms around Chella Bank. Most of the live-taken species are widely distributed along the Atlantic and Mediterranean Sea, and a few are strictly Mediterranean. The most striking feature was the occurrence of two species with planktotrophic larval development for which Chella Bank is the sole recorded locality in the Mediterranean (Episcomitra angelesae and Mitrella templadoi) and which elsewhere extremely rare (Mathilda spp.).
... Hence, they are firstly dependent on the biological activity of their reef-forming organisms, which include colonial suspension feeding invertebrates, such as cnidarians (e.g., scleractinians, stony hydrozoans and octocorals) [9,10], sponges [11], serpulids [12] and bryozoans [13]. These framework-building organisms sometimes have eastern Spain), in front of Marbella (around the Torrenueva submarine canyon), in front of Málaga and southwest off Almería [6,58,59,64]. Sampling and direct observations of the southern Alboran Sea carbonate mounds (East and West Melilla CWC mound provinces) confirmed that CWCs were the main organism involved in their formation [15,43,46,55]. Nevertheless, some of those CWC mounds are nowadays partly or even completely buried by contouritic and hemipelagic sediments [55,56,65]. ...
... Geosciences 2022, 12, 111 3 of 25 [46,55], as well as in the Cabliers bank [62,63] ( Figure 1A). Furthermore, three mound fields have been located within the contouritic terraces of the northern Alboran Sea margin (south-eastern Spain), in front of Marbella (around the Torrenueva submarine canyon), in front of Málaga and southwest off Almería [6,58,59,64]. Sampling and direct observations of the southern Alboran Sea carbonate mounds (East and West Melilla CWC mound provinces) confirmed that CWCs were the main organism involved in their formation [15,43,46,55]. Nevertheless, some of those CWC mounds are nowadays partly or even completely buried by contouritic and hemipelagic sediments [55,56,65]. ...
... The distribution and burial state of the observed CWC mounds were explained by changes in water mass dynamics during the Late Quaternary climatic cycles [15,43,46]. The northern Alboran Sea mounds were initially identified on high-resolution bathymetric maps during the analysis of the main morphotectonic characteristics of this margin [58,59]. Subsequently, some of the mounds located in front of Málaga were investigated using a Remotely Operated Vehicle (ROV) during a German expedition with the R/V POSEIDON (POS385, led by MARUM) [60]. ...
Carbonate mounds clustering in three fields were characterized on the upper continental slope of the northern Alboran Sea by means of a detailed analysis of the morphosedimentary and structural features using high-resolution bathymetry and parametric profiles. The contemporary and past benthic and demersal species were studied using ROV underwater imagery and some samples. A total of 325 mounds, with heights between 1 and 18 m, and 204 buried mounds were detected between 155 to 401 m water depth. Transparent facies characterize the mounds, which root on at least six erosive surfaces, indicating different growth stages. At present, these mounds are covered with soft sediments and typical bathyal sedimentary habitat-forming species, such as sea-pens, cerianthids and sabellid polychaetes. Nevertheless, remains of colonial scleractinians, rhodoliths and bivalves were detected and their role as potential mound-forming species is discussed. We hypothesized that the formation of these mounds could be related to favorable climatic conditions for cold-water corals, possibly during the late Pleistocene. The occurrence on top of some mounds of abundant rhodoliths suggests that some mounds were in the photic zone during minimum sea level and boreal guest fauna (e.g., Modiolus modiolus), which declined in the western Mediterranean after the Termination 1a of the Last Glacial (Late Pleistocene).
... Soft bottoms are the most widespread habitats in the bathyal stage of the Alboran Sea and elsewhere, the sediments originating either from deposition of planktonic organisms or from sediment mobilization from the shelf to the slope or along the slope due to the contouritic transport (Emig 1997;Muñoz et al. 2008;Cartes et al. 2004;Templado et al. 2012). These sediments can be of different textures (from bioclastic gravel to clay), and they generally display a higher mud content in deep areas with low hydrodynamism Ciércoles et al. 2018). ...
Benthic habitats, as well as their associated biota, have been studied in the Alboran Sea since the nineteenth century, with a very significant increase of knowledge in the last five decades. The geographical location of the Alboran Sea between three different biogeographical regions, the complex oceanography and the heterogeneous seafloor promote the coexistence of a wide diversity of habitat-forming species and, therefore, of habitat types. Some of these habitats host very complex communities in comparison to similar ones that are located northwards in the Atlantic Ocean or eastwards in the Mediterranean Sea. Moreover, some of those habitats are considered to be threatened or are experiencing very strong declines during this last decade and are probably extinct nowadays (e.g. Zostera marina beds). General knowledge of the associated biota is larger for those habitats of shallow waters in comparison to those of the deep sea and for those located in the northern sector in relation to those of the southern sector of the Alboran Sea. In most habitats, only some components of the associated biota have been studied, and there is a general lack of information for specific groups (e.g. meiofauna, Platyhelminthes, etc.).
... It has a flattened main elevation, or "guyot", and two shallower ridges culminating into "pinnacles", with steeper slopes located to the north-east and west of the main elevation and culminating at ca. 200 m depth (Lo Iacono et al. 2008, 2012. The uneven topography with steep flanks, flat summit, rocky outcrops and sedimentary moats (Lo Iacono et al. 2008;Muñoz et al. 2008) offers a wide variety of bottom types (e.g. rhodolith beds, detritic sandy bottoms, coral-rubble bottoms, rocky bottoms, hemipelagic muddy bottoms), which host a great diversity of habitats and species. ...
Chella Bank (also known as Seco de los Olivos seamount) is a volcanic submarine elevation (76-700 m deep) located ca. 16 km off the southern coast of Spain, within the Alboran Sea, in the Atlantic-Mediterranean transition zone. It represents a biodiversity hotspot for Europe, with more than 600 species listed to date, and contains several habitats included in the EU Habitats Directive. During three ship-based expeditions, several areas of Chella Bank were surveyed and sampled in a depth range of 95-729 m, resulting in new records that improve our knowledge on poorly studied phyla, such as bryozoans.
... Presence of structural relief with intense scouring at the base of the relief is proof of current action induced turbulence around the Lacking sediment stratification with sediment cover at the peak of the drift structure, parallel streamlined sediment horizons at the distal end of the drift structural high. Erosional features around structural highs caused due to bottom current action have also been reported for some parts of the Mediterranean Sea in earlier studies (Lo Iacono et al. 2008;Muñoz et al. 2008) but without detailed analyses of interplay with current controlled processes. Slope channels prominently located at the basin walls do not interact directly with the bottom currents as no such evidence from their morphology was found. ...
Geomorphic analysis utilizing multibeam bathymetry and sediment profiler data along with conductivity, temperature and depth (CTD) measurements was undertaken to investigate morphological aspects of bottom current features that prevail in the area. The aim of the study was to deduce the prevailing water mass in the area and to infer interactions between water mass and seabed of South Eastern Arabian Sea. Morphological and bottom current features were identified and analysed. Based on morphological components and their structural orientation, deduction of flow pattern and direction of current flow in the area were attempted. Deconstructing structural aspects of typical bottom current features such as contourite drifts and scours reveal origin under influence of consistent exogenic bottom current having definitive flow pattern. Sub-surface seismic profiles were analysed to infer the presence of a consistently aggrading seafloor. The aspect distribution computed exhibits a prominent trend ranging between 200° and 275° indicating NNW-SSE orientation of erosive features which is usually synonymous with flow direction in the area. Backscatter intensity analysis undertaken for the area revealed seafloor with patches of loose to compact surface sediment distribution. Variation in reflection intensity level from surface sediments was utilized to demarcate zones that are susceptible in future to consistent turbulence-induced erosion. Temperature salinity (TS) diagram for values from CTD measurements was plotted overlaying isopycnals and the resulting plots tagged for various water masses that prevail in the Arabian Sea. Owing to the depth of the study area (~ 1800 m) and structural orientation of bottom current features, dominant oceanographic agent from TS plot was deduced to be the North Indian Deep Water (NIDW). Surface and sub-surface morphology of existing features were interpreted for influence of bottom current action. Geomorphic analysis of seabed is an efficient method to understand the flow pattern and of prevailing water masses and can be applied as passive indicators of bottom current flow. This approach of deducing flow pattern and intensity of water mass movement by analysing morphology of the undersea features can be effectively used globally especially in areas where adequate data and observations for deep water masses are scarce.
... The Alboran Sea displays a relatively complex seafloor geomorphology, including three main sub-basins (i.e. West, East and South Alboran Basins) separated by the Alboran Ridge, a major NE-SW oriented structural high (Muñoz et al., 2008;Lo Iacono et al., 2014;Gràcia et al., 2006. The shelf of the Alboran Sea displays a variable extension, from 3.5 to 12 km, and is bounded by the shelf edge at a depth of 100-115 m. ...
... The sediment dynamics of the margin are strongly controlled by the prevailing along-slope current regimes, which gave origin to large contourite deposits (Ercilla et al., , 2019Juan et al., 2016). They are locally interrupted by turbidite fans, mass-wasting deposits and volcanic outcrops (Muñoz et al., 2008;Lo Iacono et al., 2008;Ercilla et al., 2019). The Alboran Sea is mainly characterized by a siliciclastic sedimentation controlled by the river sources, together with the aeolian inputs as the main source of terrigenous sediments (Moreno et al., 2002). ...
Megabenthic assemblages in deep-sea sedimentary environments receive far less attention than those occurring on rocky environments, despite they have been widely impacted by destructive trawling activities, mainly due to their association with important commercial species. ROV dives conducted on bathyal muds of the Alboran Sea continental slope (western Mediterranean) were used to characterize megabenthic assemblages, as well as assess their response to trawling and benthic litter. We identified a multispecific assemblage, dominated by the isidid Isidella elongata, and two monospecific assemblages composed by the sea-pens Funiculina quadrangularis and Kophobelemnon stelliferum. These assemblages are defined as vulnerable marine ecosystems by international institutions. Trawled areas exhibit significant low densities of habitat-forming species and a striking impoverishment of habitat complexity and diversity. Plastic debris and lost fishing gears were the most abundant components of the marine litter. This study highlights the destructive effects of human activities on bathyal muds, emphasizing the need for urgent conservation measures.
... The Pliocene-Quaternary tectonics of the Alboran Basin and its margins show the superposition of transpressive and transtensive structures that have been attributed to different mechanisms including changes in far-field stress, slab rollback and mantle delamination (Calvert et al., 2000;Gutscher et al., 2002;Martínez-García et al., 2013Petit et al., 2015;Thurner et al., 2014). At present day, GPS velocities define an Alboran tectonic domain in between the African and Iberian rigid blocks ( Fig. 1) (Neres et al., 2016;Palano et al., 2013Palano et al., , 2015. Based on the seismicity (Fig. 2), a present-day diffuse plate boundary between Africa and Eurasia was proposed in the Alboran Basin and the Betic-Rif belt (Bird, 2003;Neres et al., 2016;Palano et al., 2015). ...
... At present day, GPS velocities define an Alboran tectonic domain in between the African and Iberian rigid blocks ( Fig. 1) (Neres et al., 2016;Palano et al., 2013Palano et al., , 2015. Based on the seismicity (Fig. 2), a present-day diffuse plate boundary between Africa and Eurasia was proposed in the Alboran Basin and the Betic-Rif belt (Bird, 2003;Neres et al., 2016;Palano et al., 2015). DeMets et al. (2015) constrained the location of the rotation poles between Eurasia, North America and Africa since the Miocene. ...
... Lithosphere-scale processes and crustal heterogeneities such as mantle and lower crustal delamination have exerted a strong influence on the deformation and the structure of the Alboran Basin (Petit et al., 2015;Thurner et al., 2014). The mechanical coupling between the Alboran Domain and the subsiding lithosphere and/or slab dragging under Africa-Eurasia convergence have caused the extrusion of the Betic-Rif belt toward the southwest (Neres et al., 2016;Perouse et al., 2010;Petit et al., 2015;Spakman et al., 2018;Thurner et al., 2014). ...
Progress in the understanding and dating of the sedimentary record of the Alboran Basin allows us to propose a model of its tectonic evolution since the Pliocene. After a period of extension, the Alboran Basin underwent a progressive tectonic inversion starting around 9–7.5 Ma. The Alboran Ridge is a NE–SW transpressive structure accommodating the shortening in the basin. We mapped its southwestern termination, a Pliocene rhombic structure exhibiting series of folds and thrusts. The active
Al-Idrissi Fault zone (AIF) is a Pleistocene strike-slip structure trending
NNE–SSW. The AIF crosses the Alboran Ridge and connects to the transtensive
Nekor Basin and the Nekor Fault to the south. In the Moroccan shelf and at
the edge of a submerged volcano we dated the inception of the local
subsidence at 1.81–1.12 Ma. The subsidence marks the propagation of the AIF
toward the Nekor Basin. Pliocene thrusts and folds and Quaternary
transtension appear at first sight to act at different tectonic periods but
reflect the long-term evolution of a transpressive system. Despite the
constant direction of Africa–Eurasia convergence since 6 Ma, along the
southern margin of the Alboran Basin, the Pliocene–Quaternary compression
evolves from transpressive to transtensive along the AIF and the Nekor
Basin. This system reflects the logical evolution of the deformation of the
Alboran Basin under the indentation of the African lithosphere.
... It connects to the Jebha and Nekor fault systems at the Moroccan margin (Chalouan & Michard, 2004;Benmakhlouf et al., 2012;Capella et al., 2017). Offshore, the Alboran Ridge, which is part of the Trans-Alboran Shear Zone, is a 60 km long transpressive NE-SW elongated tectonic discontinuous structure (Muñoz et al., 2008;Ballesteros et al., 2008), made of Miocene and Pliocene sedimentary and volcanic rocks. It is locally intruded by a volcanic body in its eastern part Mauffret et al., 2007;Chalouan et al., 2008;Maad et al., 2010), while its southern termination, called the South Alboran Ridge (SAR), corresponds to a series of Mio-Pliocene sigmoid antiforms and synforms accommodating left lateral motion and uplift (Bourgois et al., 1992;Comas et al., 1992;Chalouan et al., 1997;Mauffret et al., 2007;Galindo-Zaldivar et al., 2018). ...
Since the Miocene, the thinned continental crust below the Alboran Sea and its overlying sedimentary cover have been undergoing deformation caused by both convergence of Eurasia and Africa and by deep processes related to the Tethyan slab retreat. Part of this deformation is recorded at the Xauen and Tofiño banks in the southern Alboran Sea. Using swath bathymetry and multichannel seismic reflection data, we identified different stages and styles of deformation. The South Alboran Basin is made up of Early Miocene to Pliocene sedimentary layers that correlate with the West Alboran Basin depocenter and are dominated by E‐W trending folds and thrusts. The Xauen and Tofiño Banks first recorded the phase of extension and strike‐slip movement during the slab retreat, followed by the phase of compressional inversion since the Tortonian and are now structured by tight folds, thrusts, and mud bodies. This study proposes that the Banks were located on the southern‐inherited Subduction Tear Edge Propagator (STEP) fault related to the westward migration of the Alboran domain during the Miocene. The STEP fault zone, acting as a boundary between the African block and the Alboran block, was located along the onshore Jebha‐Nekor fault and the offshore Alboran Ridge and the Yusuf fault zone. Thick‐skinned and thin‐skinned shortening occurred when slab retreat stopped, and inversion began. The present‐day style of the deformation seems to be linked to a decollement level made of undercompacted shale on top of the Ghomaride complex.
... The Pliocene-Quaternary tectonics of the Alboran Basin and its margins show the superposition of transpressive and transtensive structures that have been attributed to different mechanisms including changes in far-field stress, slab rollback and mantle delamination (Calvert et al., 2000;Gutscher et al., 2002;Martínez-García et al., 2013Petit et al., 2015;Thurner et al., 2014). At present day, GPS velocities define an Alboran tectonic domain in between the African and Iberian rigid blocks ( Fig. 1) (Neres et al., 2016;Palano et al., 2013Palano et al., , 2015. Based on the seismicity (Fig. 2), a present-day diffuse plate boundary between Africa and Eurasia was proposed in the Alboran Basin and the Betic-Rif belt (Bird, 2003;Neres et al., 2016;Palano et al., 2015). ...
... At present day, GPS velocities define an Alboran tectonic domain in between the African and Iberian rigid blocks ( Fig. 1) (Neres et al., 2016;Palano et al., 2013Palano et al., , 2015. Based on the seismicity (Fig. 2), a present-day diffuse plate boundary between Africa and Eurasia was proposed in the Alboran Basin and the Betic-Rif belt (Bird, 2003;Neres et al., 2016;Palano et al., 2015). DeMets et al. (2015) constrained the location of the rotation poles between Eurasia, North America and Africa since the Miocene. ...
... Lithosphere-scale processes and crustal heterogeneities such as mantle and lower crustal delamination have exerted a strong influence on the deformation and the structure of the Alboran Basin (Petit et al., 2015;Thurner et al., 2014). The mechanical coupling between the Alboran Domain and the subsiding lithosphere and/or slab dragging under Africa-Eurasia convergence have caused the extrusion of the Betic-Rif belt toward the southwest (Neres et al., 2016;Perouse et al., 2010;Petit et al., 2015;Spakman et al., 2018;Thurner et al., 2014). ...
Abstract. Progresses in understanding the sedimentary dynamic of the Western Alboran Basin lead us to propose a model of evolution of its tectonic inversion since the Pliocene to present-time. Extensive and strike-slip structures accommodate the Miocene back-arc extension of the Alboran Basin, but undergo progressive tectonic inversion since the Tortonian. Across the Alboran Basin, the Alboran Ridge becomes a transpressive structure accommodating the shortening. We map its southwestern termination: a Pliocene rhombic structure exhibiting series of folds and thrusts. A younger structure, the Al-Idrissi fault zone (AIF), is Pleistocene to present-day active strike-slip fault zone. This fault zone crosses the Alboran Ridge and connects southward to the transtensive Nekor Basin and the Nekor fault. In the Moroccan shelf and at the edge of a submerged volcano, we date the inception of the local shelf subsidence from the 1.81-1.12 Ma. It marks the propagation of the AIF toward the Nekor Basin. Pliocene thrusts and folds and Quaternary transtension appear at first sight as different tectonic periods but reflects the long-term evolution of a transpressive system. Despite a constant direction of Africa/Eurasia convergence since 5Ma at the scale of the southern margin of Alboran Basin, the Pliocene-Quaternary inversion evolves from transpressive to
transtensive on the AIF and the Nekor Basin. This system reflects the expected evolution of the deformation of the Alboran Basin under the indentation of the African lithosphere.
