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1.
T. Geel 《Basin Research》1995,7(4):313-336
The Alicante region, situated at the intersection of major Western Mediterranean structural units, is unique in possessing a complete marine Oligocene to early Miocene record of both platform and slope deposits. Detailed analysis of three selected platform areas in the north of the region, each showing a different tectono-sedimentary history, and comparison with coeval slope deposits in the south of the region shows that: (a) during the Rupelian to early Chattian the region formed part of the Iberian microplate and can be considered the south-eastern continuation of the NW-SE-trending Iberian Chain (folding phase between 36 and 33 Ma, updoming event at 31–29 Ma, both induced by Pyrenean collision); (b) during the late Chattian to Aquitanian it was linked to the extensional, SW-NE-orientated Valencia Trough forming part of its western margin (rifting phases at 28 and 25 Ma); (c) from the Aquitanian-Burdigalian boundary (20 Ma) onward, the region underwent NW-directed compression due to Betic collision (folding phases at 20 and 17 Ma); (d) a foreland basin formed in the late Burdigalian (18–17 Ma), continuous from the Betic Cordilleras over the Alicante region to the Balearics; (e) a purely compressive regime was superseded by strike-slip tectonics at the Langhian—Serravallian boundary. The previously formulated hypotheses of coeval compression and extension with inferred hypothetical strike-slip or other faults in or near the Alicante region is rejected on the basis that compress ional and extensional tectonics are separated in time in the Alicante region.  相似文献   

2.
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3.
A sedimentological, geochemical and palynological study of the Taravilla Lake sequence (Central Iberian Range, NE Spain) provides a detailed record of allochthonous terrigenous layers that intercalate within the lacustrine sediments over the last 2000 years. These terrigenous layers are interpreted as the result of extreme hydrological events that caused higher clastic input to the basin. Anthropogenic influence caused by fires or deforestation is rejected as the main factor generating these layers because human impact, inferred from the pollen reconstruction, was minimal when the terrigenous layers reached their greatest frequency. The reconstructed occurrence of these events in the Taravilla Lake record is coherent with the paleoflood history of the Tagus River, characterized by a notable increase of extreme events at the beginning of the Little Ice Age. The Taravilla record suggests a relationship between the occurrence of extreme hydrological events, solar variability, and the North Atlantic Oscillation for the NE Iberian Peninsula.  相似文献   

4.
The valuation of ecosystem services has primarily been conducted within the context of the economic value of these services to society. Ecosystem services research has since advanced to identify conflicts of interest between different sectors of society while prioritizing conservation actions. This approach can be important in semiarid ecosystems, where biodiversity conservation can be hindered by a lack of community awareness. In the south-eastern Iberian Peninsula, conservation is perceived by society as a barrier to the economic development provided by agricultural or tourism activities. We use the contingent valuation method to identify community perception and economic values of different ecosystem services provided by semiarid ecosystems in the south-eastern Iberian Peninsula. This method identifies the perceptions of individuals benefiting from ecosystem services and examines their willingness to pay for the maintaining of these ecosystem services. Results showed that most respondents recognized the importance of services to human well-being and were willing to conserve these services. Preferences for maintaining water and air quality showed that respondents understood the relationship between the conservation of ecosystem services and local well-being. However, responses varied greatly across categories of beneficiaries; this finding highlights a potential conflict of interest that should be considered in any decision-making processes.  相似文献   

5.
The NW Iberian Massif is part of an ancient basement that has been considered a seismically stable area with no outstanding Cenozoic tectonics. However, recent seismic activity revealed the need for better knowledge of the Cenozoic structures in the area. Because of the lack of Mesozoic deposits and the scarcity of Cenozoic sediments, as well as the intense deformation of the Pre-Mesozoic Variscan basement, it is difficult to study the Cenozoic tectonic structures. In this work, the combination of detailed structural mapping and study of geomorphological markers in the Variscan basement has allowed recognition of Cenozoic tectonic structures, kinematics and processes that otherwise would not have been identified. The identified structures have been gathered into three groups: a) NE–SW-trending strike-slip faults, mainly sinistral, b) NNW-vergent thrusts that uplift the Caurel Mountains and Galaico-Leoneses Mountains, and c) E–W and ENE–WSW thrusts that uplift the Ancares Mountains in a pop-up structure. The structures cut the Pre-Cenozoic erosion surface and affect the drainage network that shows patterns characteristic of tectonic activity. The three groups of structures define sectors with different relief showing a strong link between geomorphological elements and tectonic structures. The intense drainage reorganisations observed in the area and the deformation of Miocene–Pliocene deposits, point out to a significant Late Miocene tectonic activity in the region. Thus, the Cenozoic tectonic activity in the northwest of the Iberian Peninsula takes place during an extensive period of time which started with the episodes of compression in the Cantabrian Margin and it is identified nowadays by the recent seismic activity recorded in the north-western Iberian Peninsula (1995 and 1997 Lugo events). The seismicity is related to the Cenozoic structures identified in the area, which move under the present SE–NW horizontal maximum compression and coincide with the proposed seismogenic faults.  相似文献   

6.
b
A method based on the coda attenuation law: Q = Q 0( f/f 0)v leads to the determination of the lateral variation of coda- Q in the southern part of the Iberian Peninsula using seismograms belonging to the seismological network of the Cartuja Observatory, located in Granada. The lateral variation of Q 0 ( Q value corresponding to a reference frequency f 0 of 1 Hz) and its frequency dependence for the 1 to 5 Hz frequency range are, in general, in agreement with coda- Q values for frequencies less than about 1 Hz, previously determined in the region under study.
To determine the coda- Q values analytical functions have been used to fit the magnification curves of the vertical component short-period seismographs belonging to the Cartuja network. The problem is solved by using least-squares techniques and non-linear inversion. The determined coda- Q 0 values and its frequency dependence correlate well with several known geophysical parameters in the southern part of the Iberian Peninsula.  相似文献   

7.
The southernmost glacier in Europe formed during the Little Ice Age at the foot of the north wall of Picacho del Veleta (3 398 m) in Sierra Nevada, in the southeast region of the Iberian Peninsula (lat. 37δ03‘N, long. 3δ22‘W). The glacier gradually retreated during the last century, leaving a large talus slope at the base of the wall. The unconsolidated material covering the ice masses acted as a thermal insulator. Recent bottom temperature of snow (BTS) analyses and drillings indicate that the ice still exists within the talus. Evidence from field observations made during the period 1995–2001, revealed that large mass movements occurred during the driest summers (1998 and especially, 1999 and 2000) when the talus was snow free. These conditions suggest a direct relationship between talus stability and thermal insulation from the snow cover in areas where buried ice or decaying marginal permafrost exists.  相似文献   

8.
Irrigated terraces in the Iberian Peninsula are associated with al-Andalus; the name with which the region was known following the migration of Arabic–Berber tribes across the Strait of Gibraltar, starting from 711 AD. Several of these agricultural areas have remained in use in the west Mediterranean to the present day. Historical texts usually refer to later extensions of the original Andalusi irrigated terrace fields, yet little is known about their foundation period. In this study we examined the micromorphology and undertook physico-chemical analyses and radiocarbon dating of a buried soil found in Ricote (Murcia, Spain) to provide relevant information to understand the initial stages of terrace building within al-Andalus. Results of our study show that: (1) Andalusi peasants selected a saline Hipercalcic Calcisol developed on colluvial materials on which to build the first irrigated terraces, (2) The soil was probably cleared of bushes by fire prior to terrace construction, (3) The shifting of sediments implied in the building of terraces seems to have entailed the inversion of the original soil stratigraphy, (4) Radiocarbon dating of submillimetric fragments of charred wood embedded in the top horizon of the buried Hipercalcic Calcisol (2σ 647–778 AD) suggests the original irrigated terraces of Ricote were built shortly after the arrival of Arabic and Berber tribes in the Iberian Peninsula.  相似文献   

9.
Facies analysis across the carbonate platform developed during the Callovian–Oxfordian in the northern Iberian basin (Jurassic, Northeast Spain) is used to characterize successive stages of sedimentary evolution, including palaeoenvironmental reconstructions showing the distribution of a wide spectrum of facies, from ferruginous oolitic, peloidal, spongiolithic to intraclastic. The studied successions consist of two long‐term transgressive–regressive cycles bounded by a major unconformity with a major gap, comprising at least the upper Lamberti (Callovian) and Mariae (Oxfordian) Zones. Major transgressive peaks of these two cycles occurred at the end of the Early Callovian (late Gracilis Zone) and at the end of the Middle Oxfordian. The Callovian and Oxfordian successions were further divided into three and seven higher frequency cycles, respectively. The modelling of two sections (i.e. Ricla and Tosos) located 40 km apart in the more subsident open platform areas, allows the reconstruction of two curves showing a similar evolution of long‐term sea‐level changes that are in theory eustatic, though subject to uncertainties derived form the assumptions required for their construction. The changes affecting the northern Iberian basin seem to reflect nearly homogeneous subsidence (rates around 2 cm kyr?1) combined with possible eustatic changes including an Early Callovian rise, a fall at the middle Callovian–earliest Oxfordian (i.e. the Anceps–Mariae Zones), with average long‐term rates around 2 cm kyr?1 (total fall of 40–60 m), a period of lowstand at the Early–Middle Oxfordian transition and a long‐term rise at the Middle–Late Oxfordian transition (Transversarium and Bifurcatus Zones). Facies distribution across the Iberian platform indicates a progressive Middle–Late Callovian relative sea‐level fall rather than a rapid relative sea‐level fall at the end of the Callovian. After this falling episode, the progressive onlap over the swell areas during the Early Oxfordian and at the beginning of the Middle Oxfordian indicates a period of accommodation gain, which is explained by the combined effects of continuous subsidence across the platform and reduced sedimentation rates in spite of the possible eustatic lowstand. Eustatic lowstand, combined with other factors (ocean water circulation, volcanism) could help to explain the loss of carbonate production during the latest Callovian–Early Oxfordian, previous to the widespread eustatic rise and warning recorded at the onset of the Transversarium Zone (Middle Oxfordian).  相似文献   

10.
The landscape of today's central Iberian Peninsula has been shaped by ongoing tectonic activity since the Tertiary. This landscape comprises a mountain ridge trending E–W to NW–SE, the Central System, separating two regions of smooth topography: the basins of the rivers Duero and Tajo. In this study, we explore interrelationships between topography and tectonics in the central Iberian Peninsula. Regional landscape features were analysed using a digital elevation model (DEM). Slope gradients and slope orientations derived from the DEM were combined to describe topographic surface roughness. Topography trend-surfaces inferred from harmonic analysis were used to define regional topographic features. Low roughness emphasizes the smooth nature of the basins' topography, where surfaces of homogeneous slope gradient and orientation dominate. High roughness was associated with abrupt changes in gradient and slope orientation such as those affecting crests, valley bottoms and scarp edges present in the mountain chain and in some deep incised valleys in the basins. One of the applications of roughness mapping was its capacity to isolate incised valley segments. The area distribution of incised rivers shows their prevalence in the east. On a regional scale, the topographic surface can be described as a train of NE–SW undulations or waves of 20 km wavelength. These undulations undergo changes in direction and interruptions limited by N–S-trending breaks. E–W and NE–SW troughs and ridges clearly mark structural uplifts and depressions within the Central System. These structures are transverse to the compressive NW–SE stress field that controlled the deformation of the central Iberian Peninsula from the Neogene to the present. They represent the upper crustal folding that accommodates Alpine shortening. N–S breaks coincide with Late Miocene faults that control the basins' sedimentation. Further, associated palaeoseismic structures suggest the recent tectonic activity of N–S faults in the eastern part of the Tajo Basin. Apatite fission track analysis data for this area suggest the occurrence of a significant uplift episode from 7 to 10 Ma which induced the river incisions appearing in the roughness map. N–S and NE–SW faults could be seismogenic sources for the current moderate to low seismic activity of the east Tajo Basin and southeast Central System. Although N–S fault activity has already been established, we propose its significant contribution to shaping the landscape.  相似文献   

11.
In this review we compile results on interactions above and below ground and food web functioning in an arid environment at the Baza Basin, in the Iberian southeast. Our data reveal that herbivory is difficult to estimate in our system. Some herbivores (rabbits) and granivores (Messor ants) create nutrient and detritus-rich patches, with important effects on the diversity and abundance of species both above and below ground. Fluctuations of prey availability, especially those caused by changes in their circadian rhythms, provoke seasonal migrations and omnivory in predators. We also present experimental evidence of the effects of interactions between aboveground and belowground macroarthropods on litter degradation; belowground detritivores are responsible for a high percentage of ground surface litter decomposition. We demonstrate that belowground herbivores and decomposers can dramatically change aboveground multitrophic interactions. Finally, we identify the biotic and abiotic factors controlling aboveground and belowground macrofaunal distribution at a broad scale. We conclude that trophic interactions in this semi-arid area are numerous and complex with many of the interactions involving more than two or three organisms. The interactions between above- and belowground organisms added complexity to this system. These habitats in which organisms deal with extreme abiotic conditions promote odd interactions resulting in an increase of biodiversity. Finally, despite the large research effort devoted to understanding food web structure and dynamics in this area recently, our state of knowledge is still far from providing a complete picture of interactions and their implications in the regulation and functioning of the system.  相似文献   

12.
Forward stratigraphic models usually display sediment types on simulated stratigraphic profiles as ‘facies’ defined only by their depth of deposition. More recently, ‘facies’ have been defined and displayed in terms of the dominant processes of deposition (e.g. in situ growth, pelagic production, turbidite deposition). Standard carbonate facies; that is, the Dunham classification, are defined by rock textures and grain composition that imply that a combination of processes acted together to generate a facies. For example, a bioclastic wackestone is a matrix‐supported rock containing up to 90% matrix and > 10% shelly grains. In terms of modelled processes, the muddy matrix could be generated by: (i) reworking of the shallow platform sediments, (ii) from pelagic deposition, or (iii) in situ production. A traditional depth of deposition process display would not be able to distinguish such a wackestone from any other facies deposited at this water depth and a majority process display would not combine reworked, pelagic muds and in situ contribution in one simulated ‘facies’. This paper introduces a new scheme that enables forward models to output simulated facies defined by a range of values for each of the controlling processes and thereby predicts rock textures within simulated stratigraphies. This approach has been applied to the Jurassic carbonate ramps of the Iberian Basin in northeastern Spain. It is shown to provide more accurate information about the processes that are being simulated, allowing more direct comparisons to be made with the facies observed in the field and providing potential for a more rigorous method for assessing the ‘goodness of fit’ of a simulated stratigraphy.  相似文献   

13.
Many works in the last decades underline the role of evaporites, not just as a conditioning factor but as the engine for subsidence and eventually basin inversion. The western Mediterranean alpine ranges are being investigated in this regard because of the presence of discontinuous units of Permian to Triassic evaporites, deposited in the western Tethys basins. This work presents a thorough analysis of two particular structures (Cañada Vellida and Miravete anticlines) in the intraplate Maestrazgo basin (eastern Iberian Chain, Spain) in which evidence to support their reinterpretation as salt-driven structures have been recently reported. Our analysis includes (i) a comprehensive stratigraphic and structural study of the folds along their entire trace, (ii) the compilation of thickness and distribution of evaporite–bearing and supraevaporite units, paying special attention to changes in the thickness of units in relation to anticlines, and (iii) the study of fault patterns, sometimes in relation to the mechanical stratigraphy. All three aspects are also documented and discussed on a regional scale. The new data and interpretations reported here reinforce the extensional origin of the Late Jurassic–Early Cretaceous basins, and the role of regional extensional tectonics as the responsible for the development of first-order syn-sedimentary normal fault zones driving the formation and evolution of sub-basins. These basins were subsequently inverted and deformed, including the formation of complex, box-geometry anticlines that, in their turn, controlled deposition in Cenozoic basins. The review of the arguments that support the alternative of salt tectonics for the origin of such anticlines has allowed us to delve into the sedimentary and tectonic evolution of the inverted extensional basins and to propose a specific model for the development of these faulted anticlines. The role of salt levels and other interlayered detachments in the structuring of sedimentary basins and their inversion is also pondered. The observations in the eastern Iberian Chain reported here have implications to assess ongoing reinterpretations in terms of salt tectonics in other alpine basins and ranges of the western Mediterranean.  相似文献   

14.
During the middle and late Holocene, the Iberian Peninsula underwent large climatic and hydrologic changes, but the temporal resolution and regional distribution of available palaeoenvironmental records is still insufficient for a comprehensive assessment of the regional variability. The high sedimentation rate in karstic, meromictic Montcortès Lake (Catalan pre-Pyrenees) allows for a detailed reconstruction of the regional palaeoecology over the last 5,340 years using diatom analysis, aquatic pollen, sedimentological data, and historic documentary records. Results show marked fluctuations in diatom species assemblage composition, mainly between dominant Cyclotella taxa and small Fragilariales. We suggest that the conspicuous alternation between Cyclotella comta and C. cyclopuncta reflects changes in trophic state, while the succession of centric and pennate species most likely reflects changes in the hydrology of the lake. The diatom assemblages were used to identify six main phases: (1) high productivity and likely lower lake levels before 2350 BC, (2) lower lake levels and a strong arid phase between 2350 and 1850 BC, (3) lake level increase between 1850 and 850 BC, (4) relatively high lake level with fluctuating conditions during the Iberian and Roman Epochs (650 BC–350 AD), (5) lower lake levels, unfavourable conditions for diatom preservation, eutrophication and erosion triggered by increased human activities in the watershed during the Medieval Climate Anomaly (900–1300 AD), and (6) relatively higher lake levels during the LIA (1380–1850 AD) and afterwards. The combined study of diatoms, algae and pollen provides a detailed reconstruction of past climate, which refines understanding of regional environmental variability and interactions between climate and socio-economic conditions in the Pyrenees.  相似文献   

15.
The aim of this study is to assess the Iberian populations of Forsskaolea tenacissima L. according to its biogeographical interest, habitat, geographical range and conservation status. Results point out that they are restricted to gravel wadis of Tabernas Desert (SE Spain), are scarcely included in protected areas and represent historically isolated populations with relict behaviour. We also describe a new association, Senecioni-Forsskaoleetum tenacissimae. Conservation status of species is cause for concern and two conservation actions must be carried out. Firstly, protected areas should house Forsskaolea populations and secondly, phytosociological characterization of a community allows inventorying its habitat and directing conservation efforts to community level.  相似文献   

16.
The distribution and structure of the Mesozoic and Cenozoic cover within the central part of the North Iberian Margin (Bay of Biscay) is analysed based on a dense set of 2D seismic reflection lines and logs. The integration of well data allows the recognition of seven seismostratigraphic units and the construction of a surface that illustrates the 3D morphology of this area at the time of the Jurassic rifting. The study zone comprises what is known as Le Danois Bank, a basement high, and the Asturian Basin, one of the sedimentary basins originated during the Iberian rifting at the end of the Paleozoic. Its development continued with the oceanisation of the Bay of Biscay as a failed arm of the Atlantic rift; later, during the Cenozoic, a drastic change in tectonic regime induced the partial closure of Biscay and building up the Cantabrian?Pyrenean chain along the northern border of Iberia. This compressional period left its imprint in the Asturian Basin sediments in the form of a mild inversion and general uplift. The geometry of the basin bottom appears as an asymmetric bowl thinning out towards the edges, with a main E‐W depocenter, separated by E‐W striking faults from a secondary one. Those bounding faults show twisted trends in the north, interpreted as a consequence of the compressional period, when a transfer zone in a N‐S direction formed between the two E‐W striking deformation fronts in Biscay. This study shows that the transfer zone extends further to the west, reaching the longitude of Le Danois Bank. The maximum thickness of the filling within the Asturian Basin is estimated in more than 10 km, deeper than assessed in previous studies. The recognition of frequent halokynetic structures at this longitude is another observation worth to remark. Based on this study, it is suggested that the basin formed on top of a distal basement block of stretched crust limiting with the hyperextended rifted domain of Biscay. This location largely conditioned its deformation during the late compression.  相似文献   

17.
Integration of extensive fieldwork, remote sensing mapping and 3D models from high-quality drone photographs relates tectonics and sedimentation to define the Jurassic–early Albian diapiric evolution of the N–S Miravete anticline, the NW-SE Castel de Cabra anticline and the NW-SE Cañada Vellida ridge in the Maestrat Basin (Iberian Ranges, Spain). The pre shortening diapiric structures are defined by well-exposed and unambiguous halokinetic geometries such as hooks and flaps, salt walls and collapse normal faults. These were developed on Triassic salt-bearing deposits, previously misinterpreted because they were hidden and overprinted by the Alpine shortening. The Miravete anticline grew during the Jurassic and Early Cretaceous and was rejuvenated during Cenozoic shortening. Its evolution is separated into four halokinetic stages, including the latest Alpine compression. Regionally, the well-exposed Castel de Cabra salt anticline and Cañada Vellida salt wall confirm the widespread Jurassic and Early Cretaceous diapiric evolution of the Maestrat Basin. The NE flank of the Cañada Vellida salt wall is characterized by hook patterns and by a 500-m-long thin Upper Jurassic carbonates defining an upturned flap, inferred as the roof of the salt wall before NE-directed salt extrusion. A regional E-W cross section through the Ababuj, Miravete and Cañada-Benatanduz anticlines shows typical geometries of salt-related rift basins, partly decoupled from basement faults. These structures could form a broader diapiric region still to be investigated. In this section, the Camarillas and Fortanete minibasins displayed well-developed bowl geometries at the onset of shortening. The most active period of diapiric growth in the Maestrat Basin occurred during the Early Cretaceous, which is also recorded in the Eastern Betics, Asturias and Basque-Cantabrian basins. This period coincides with the peak of eastward drift of the Iberian microplate, with speeds of 20 mm/year. The transtensional regime is interpreted to have played a role in diapiric development.  相似文献   

18.
High-resolution geochemical analysis of a 6-m-long sediment core from Zoñar Lake, southern Spain, provides a detailed characterization of major changes in lake and watershed processes during the last 4,000 years. Geochemical variables were used as paleolimnological indicators and complement Zoñar Lakes’s paleoenvironmental reconstruction based on sedimentological and biological proxies, which define periods of increasing allochthonous input to the lake and periods of dominant autochthonous sedimentation. Chemical ratios identify periods of endogenic carbonate formation (higher Ca/Al, Sr/Al and Ba/Al ratios), evaporite precipitation (higher S/Al, Sr/Al ratios), and anoxic conditions (higher Mo/Al, U/Th ratios and Eu anomaly). Higher productivity is marked by elevated organic carbon content and carbonate precipitation (Mg/Ca). Hydrological reconstruction for Zoñar Lake was based on sedimentological, mineralogical and biological proxies, and shows that lower lake levels are characterized by Sr-rich sediments (a brackish lake with aragonite) and S-rich sediments (a saline lake with gypsum), while higher lake levels are characterized by sediments enriched in elements associated with alumino-silicates (Al, K, Ti, Fe, trace and rare earth elements), reflecting fresher conditions. Geochemical indicators also mark periods of higher detrital input to the lake related to human activity in the watershed: (1) during the Iberian Roman Humid Period (650 BC–AD 300), around the onset of the Little Ice Age (AD 1400), during the relatively drier Post-Roman and Middle Ages (AD 800–1400), and over the last 50 years, due to mechanized farming practices. Heavy metal enrichment in the sediments (Cu and Ni) suggests intensification of human activities during the Iberian Roman Period, and the use of fertilizers during the last 50 years.  相似文献   

19.
Semi-arid landscapes in the western Mediterranean have been used for millennia, resulting in large-scale transformations and widespread degradation. In some instances, these degraded environments have been unable to recover spontaneously, and ambitious restoration programs have been launched over the last decades to improve landscape conditions. Ecological restoration may speed up succession, promote more complex communities and increase their functionality. But uncertainty in the definition of restoration objectives, failure to identify most efficient practices and, particularly, socio-economic and cultural constrains may compromise future actions. Here, we review recent advances in the restoration of semi-arid vegetation cover in the Iberian southeast, discuss future challenges and suggest two key steps towards increasing the consistency and efficiency of restoration programs: emphasis on ecosystem services, and implementation of participative and adaptive management practices.  相似文献   

20.
《Basin Research》2018,30(Z1):382-400
High‐resolution acoustic and seismic data acquired 100 km offshore Cape São Vicente, image with unprecedented detail one of the largest active reverse faults of the SW Iberian Margin, the Horseshoe Fault (HF). The HF region is an area seismogenically active, source of the largest magnitude instrumental and historical earthquake (Mw > 6) occurred in the SW Iberian Margin. The HF corresponds to a N40 trending, 110 km long, and NW‐verging active thrust that affects the whole sedimentary sequence and reaches up to the seafloor, generating a relief of more than 1 km. The along‐strike structural variability as well as fault trend suggests that the HF is composed by three main sub‐segments: North (N25), Central (N50) and South (N45). Swath‐bathymetry, TOBI sidescan sonar backscatter and parametric echosounder TOPAS profiles reveal the surface morphology of the HF block, characterized by several, steep (20°) small scarps located on the hangingwall, and a succession of mass transport deposits (i.e. turbidites) on its footwall, located in the Horseshoe Abyssal Plain. A succession of pre‐stack depth‐migrated multichannel seismic reflection profiles across the HF and neighbouring areas allowed us to constrain their seismo‐stratigraphy, structural geometry, tectono‐sedimentary evolution from Upper Jurassic to present‐day, and to calculate their fault parameters. Finally, on the basis of segment length, surface fault area and seismogenic depth we evaluated the seismic potential of the HF, which in the worst‐case scenario may generate an earthquake of magnitude Mw 7.8 ± 0.1. Thus, considering the tectonic behaviour and near‐shore location, the HF should be recognized in seismic and tsunami hazard assessment models of Western Europe and North Africa.  相似文献   

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