This paper presents an analysis of the vulnerability (AVI Index) and hazard of flooding by sea level rise (FRI Index) in the central Algarve (South Portugal), between the cities of Portimão and ...Tavira, which is an area of intense urban impact and fast growing tourism. The vulnerability index was calculated using the following parametric thematic maps: lithology, geomorphology, slopes, elevations, distances, bathymetry, variations of the coastline, wave height and activity, variations of sea level and tidal range. The AVI Index was validated by the results obtained from the analysis of the risk of flooding from the FHI Index applied to several time horizons (X0-present, X1-100 years, X2-500 years, X3-1000year, X4-Storm and X5-Tsunami). Application of GIS and remote sensing techniques, viz. spatial analysis, interpolation processes and geostatistical analysis, permitted a regional forecasting model of change in the mean sea level and the ensuing consequences to be established. Analysis of the obtained results shows an increase in potential flood zones in populous coastal tourist areas with a high risk of exposure and a significant spatial extent of 8.84km2 only in Faro municipality. The assessment and delineation of other endangered sectors could contribute to designing appropriate long- term management policies for the coastal of Central Algarve.
Virtual fieldtrips in palaeontology and geology offer an expanded environment to make field sites more accessible for a broader audience. Based on extensive experience working in upper Neogene ...deposits in the province of Huelva, on the western edge of the Guadalquivir Basin, we have selected 10 sites for their regional palaeontological-geological interest (geosites). By applying geoinformatic tools, we have produced a virtual 3D tour of the georeferenced geosites, integrating multiple thematic digital layers (including geological maps, topographical maps, a digital terrain model and orthophotos). Each stop in the tour contains descriptive and graphic elements that can be viewed in free virtual globes (e.g., Google Earth), combined with diagrams, photographs and information sheets that quantitatively assess the cultural tourism, scientific and educational value of the geosite. From this digital 3D geodatabase, we propose a virtual flight itinerary that can be displayed in compatible video formats and using new technologies, such as smartphones, tablets or iPads.
Many on-shore studies focused on high energy marine events occurred in the Gulf of Cadiz have been published since the 1990s. Most of the findings came from sedimentary, palaeontological and ...geomorphological records on estuaries, marshes, beach-barriers (spit-bars), and some coastal lowlands. Recent off-shore investigations in SW Iberia considered turbidite deposits as a proxy to recognise palaeoearthquakes in this zone. The comparison of datasets from both on-shore and off-shore records indicate that at least five tsunami events generated by strong earthquakes affected this area during the last 7000 years, previous to the more recent and well-documented 1755 AD Lisbon earthquake tsunami event. The catalogue of Holocene palaeotsunami presented here is supported by geological and geomorphological evidences, but also for archaeoseismic and palaeoseismic evidence and written reports for the more recent events occurred during historical times. The recurrence interval for these catastrophic events can be bracketed between 1200 and 1500 years.
Rural geotourism looks at the natural resources of the territory as a means of promoting a specialized, educational, sustainable tourism. This is an increasingly sought-after activity. This paper ...presents a rural georoute across a high mountain village, highlighting the remarkable value of the geological heritage of biological trace fossils and physical sedimentary structures exposed on street pavements and façades of houses. A series of tourist georesources were created and implemented: educational and interpretive panels, videos, QR codes, geoapps and games, all of which promote and disseminate the exceptional geological content and the history of the earth through the use of new technologies (smartphones, ipod, etc.). All this is intended as a means to make geotourism a natural tourism, favoring experiences, whilst explaining the natural environment and its temporal and spatial dimensions, offering opportunities for socio-economic development and job creation in rural areas with problems of depopulation.
This study analyses coastal geomorphic responses to the various sea-level changes that occurred throughout the Quaternary period in the Mediterranean and Atlantic coasts of Spain. Particular emphasis ...is paid to the geomorphic and stratigraphic record of the changes in amplitude, duration and frequency associated with the major gradual climate changes observed in marine cores and ice oxygen-isotope records during the Early and Middle Pleistocene (ca. 2.6Myr; ca. ~1.4–0.8Myr; ca. ~0.4–0.2Myr) and also with the rapid and abrupt Late Pleistocene and Holocene climate changes. With this aim, the best preserved and most complete sedimentary sequences known in the Spanish Mediterranean and Atlantic coasts covering diverse geodynamic and climatic contexts were selected and analyses. This study is mainly based on field investigation of geomorphic, sedimentologic and stratigraphic features of mapped morphosedimentary units, combined with reliable chronological data. The analyses include the interpretation of sedimentary environments, the 3-D reconstruction of facies and morphosedimentary unit arrangement, paying special attention to the lateral geomorphic relationships between marine and terrestrial morphosedimentary units developed during interglacials under sea-level highstand scenarios. The interglacials occurred during four key Quaternary periods might be related with major gradual changes associated with glacial climate cycles reported from marine and ice oxygen-isotope records. Almost coeval changes in geomorphological styles are reported from all studied areas, regardless of their specific geodynamic context. Results from the Mediterranean realm suggest that this area is more sensitive to climatic and sea level variability than the Spanish Atlantic coast, particularly in the case of rapid and abrupt changes.
► Use of combined geomorphology, facies analysis and geochronology is recommended. ► Relations of sea level and climate were deduced from highstands during the Quaternary. ► Changes in coastal geomorphological styles suggest climate forcing.
Detailed mapping based on aerial photographs at various scales, analysis of morpho-sedimentary units, and radiocarbon dating of the prograding beach-ridge complex of Campo de Dalı́as (Almerı́a) allow ...the differentiation of six prograding units. These are called: H
1, 7400–6000 cal BP; H
2, 5400–4200 cal BP; H
3, 4200–3000 cal BP; H
4, 2700–1900 cal BP; H
5, 1900–1100 cal BP; and H
6, 500 cal BP–Present. H-units are deposited during periods of high relative sea level and increased sediment input to the coast. They are bounded by large swales or erosional surfaces associated with lower sea levels and reduced input of sediment to the coast; these correspond to short periods of increased aridity inside the general arid trend recorded in the Western Mediterranean since 5.4 ka. Changes in the flux of Atlantic superficial waters into the Mediterranean Sea, and relative strength of the W/SW winds account for the recorded oscillations of relative sea level.
We deduce a decadal periodicity for the deposition of a beach ridge and the adjacent swale, and suggest that it is related to fluctuations of the North Atlantic Oscillation (NAO) index and to variations of solar activity. The duration of H-units shows a quasi-millennial periodicity punctuated by short (hundred years) episodes of reduced progradation or erosion representing events of increased aridity likely to be related to Bond's Holocene cold events.
Palaeontological, geomorphological and sedimentological data supported by isotopic dating on Oxygen Isotopic Stage (OIS) 5e deposits from the Spanish Mediterranean coast, are interpreted with the aim ...of reconstructing climatic instability in the Northern Hemisphere. Data point to marked climatic instability during the Last Interglacial (OIS 5e), with a change in meteorological conditions and, consequently, in the sedimentary environment. The oolitic facies generated during the first part of OIS 5e (ca. 135 kyr) shift into reddish conglomeratic facies during the second part (ca. 117 kyr). Sea surface Temperature (SST) and salinity are interpreted mainly on the basis of warm Senegalese fauna, which show chronological and spatial differential distribution throughout the Western Mediterranean. Present hydrological and meteorological conditions are used also as modern analogues to reconstruct climatic variability throughout the Last Interglacial, and this variability is interpreted within the wider framework of the North Atlantic record. All the available data indicate an increase in storminess induced by an increase in the influence of north-westerlies, a slight drop of SST in the northern Western Mediterranean, and an important change in meteorological conditions at the end of OIS 5e (117 kyr). These changes correlate well with the decrease in summer insolation and with the climatic instability recorded in North Atlantic high latitudes.
This study represents the first paleoseismic approach in Spain in which archaeological remains are considered. The ancient Roman city of Baelo Claudia (1st–4th centuries AD), located at the axial ...zone of the Gibraltar Strait (Cadiz, south Spain), contains abundant disrupted architectural relics and ground collapses (i.e. landsliding, liquefacion) probably related to historic earthquake damage of intensity IX–X MSK. The archaeological stratigraphy of the city evidence two major episodes of abrupt city destruction bracketed in AD 40–60 and AD 350–395 separated by an intervening horizon of demolition for city rebuilding, otherwise characteristic for many earthquake-damaged archaeological sites in the Mediterranean. The second episode led the eventual city abandonment, and it is evidenced by good examples of column collapse, distortion, failure and breakdown of house and city walls, and pavement warping and disruptions documented during different archaeological excavations, which can be catalogued as secondary coseismic effects. Main damaged relicts observable today are the set of pop-up like arrays and warping developed in the ancient Roman pavement. Their analysis indicate an anomalous westwards ground displacement oblique to the main gentle southward slope of the topography, as also evidence failures, collapses and breakdown of walls and columns, suggesting that stress acted in a broad SW–NE/WSW–ENE orientation consistent whit the expectable motion along the largest NE–SW strike-slip faults of the zone, which in turn can be catalogued as seismic sources of moderate events (ca. 5 mb). Major disruptions and city abandonment were hesitantly related to relatively far strong earthquakes occurred during the late 4th century AD in the Mediterranean or western coast of Iberia by Menanteau et al. Menanteau, L., Vanney, J.R., Zazo, C., 1983. Belo II : Belo et son environment (Detroit de Gibraltar), Etude physique d'un site antique. Pub. Casa de Velazquez, Serie Archeologie 4., Ed. Broccard, París.. However, this study indicates that the occurrence of close moderate earthquakes jointly with the unstable character of the ground at the zone (site effect) is a more reliable hypothesis to explain the observed deformations.
Sea level and climate changes archived in various coastal environments during the last part of the last glacial and present interglacial periods are investigated by interpolating available ...geomorphology, sedimentology, palaeontology and geochronology data. The coastal response to these changes depended on the environment and geographic location. Changes of sea level during the rising, transgressive phase are well recorded in the sedimentary filling of the estuaries, whereas during the phase of highstand they are best recorded in beach–barrier environments. The postglacial rise of sea level took place in two phases: a rapid rise until 6500
cal
BP, and a second phase of near stability with minor oscillations of metric magnitude. Regarding climate changes, there is no record of changing temperatures in the coastal zones of southern Spain, although there is in precipitation and wind intensity/velocity. After 7–5
cal
ka
BP, the general climatic trend towards aridity was punctuated by several short-lived (centennial) episodes of increased aridity that occurred with a millennial cycle, often coincident with Bond cool events and, in some cases, with decreases of sea surface temperatures. The absence of human intervention in vegetation composition until 2000
BP suggests that most environmental coastal shifts were climatically driven.
Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series) analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits ...along the Spanish peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the warm ‘Senegalese’ fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of the coral
Cladocora caespitosa, found in a layer that also contains
Strombus bubonius, confirms the occurrence of warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface temperature, assuming constant salinity) during the last interglacial and at least two interglacials of the Middle Pleistocene in the western Mediterranean.
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