Vera Basin Research Articles

New early Pliocene Rhinocerotidae findings from Tuscany (Italy) and the Pliocene rhinocerotine record in Italy

An almost complete mandible from the Lower Pliocene deposits of Arcille (Tuscany) is described and investigated for the first time. The specimen is assigned to Pliorhinus megarhinus, which is documented in Italy from the latest Miocene to the mid-Pliocene. The studied specimen is larger than Stephanorhinus etruscus and S. jeanvireti, and morphologically fits P. megarhinus from the Early Pliocene of Montpellier (France), Vera Basin (Spain) and Val di Pugna Fangonero (Italy). This specimen represents the first stratigraphically well-documented Pliocene record of this species in Italy, the previous discoveries dating back to the 19th century or the beginning of the 20th century, hence lacking stratigraphic control. According to the obtained results, it is possible to assess the occurrence of P. megarhinus during the earliest Pliocene in Italy as well as to confirm the long-lasting persistence of this species, whose fossil record covers a timespan between 6.7 Ma and 3.5 Ma. During that time, P. megarhinus did seemingly undergo a trend of body mass reduction.

New Pliocene Rhinocerotidae findings from the Iberian Peninsula and the revision of the Spanish Pliocene records

A fragmentary mandible from the early Pliocene of the Vera Basin is here investigated to clarify its taxonomic position. The studied specimen is here assigned to Pliorhinus megarhinus, documented in Europe from the latest Miocene to the mid-Pliocene. The morphometrical comparison reveals that this taxon is larger than Stephanorhinus etruscus and S. jeanvireti but overlaps with Dihoplus schleiermacheri. P. megarhinus and D. schleiermacheri differ in some characters of the lower molars, such as the length of the metalophid and the shape of the trigonid in occlusal view, thus allowing new considerations on the Pliocene Spanish rhinocerotine record. According to the results here obtained, three species are at least documented in Span during the Pliocene: P. megarhinus, P. miguelcrusafonti, and S. etruscus. The presence of S. jeanvireti has to be verified and confirmed by further evidence. The presence of Dihoplus schleiermacheri as a relict taxon in the Pliocene of Spain is here discarded.

La primera tecnología de obtención de cobre en la península ibérica. Aproximación experimental a la metalurgia calcolítica de la cuenca de Vera (Almería)

Exponemos los resultados de un estudio experimental dirigido a mejorar la interpretación sobre la primera tecnología de obtención de cobre en la península ibérica. Según los datos de las mediciones y de los análisis de laboratorio, en el proceso metalúrgico es más determinante la ejecución de operaciones breves en estructuras pequeñas, abiertas y sencillas que otros elementos técnicos como el sistema de inyección de aire o el tipo de combustible. El uso de carbón y del fuelle no es estrictamente necesario, bastando un simple hogar de leña y uno o dos tubos de soplado. La experimentación con un alto grado de realismo sobre un caso concreto, la cuenca de Vera en Almería, ha permitido corroborar que la concentración de arsénico en los objetos de cobre es accidental: se debe a la transformación de minerales oxídicos polimetálicos. Los resultados de este trabajo confirman la hipótesis que sostiene que la primera producción de metal en la península ibérica era de tipo doméstico con una organización simple. Esta actividad pudo desarrollarse a partir de la base tecnológica de la producción cerámica sin necesidad de un gran salto cualitativo.

Late Miocene deep-sea trace fossil associations in the Vera Basin, Almería, Southeastern Spain

The Vera Basin in southeastern Spain was a small, tectonically active depocenter throughout the Miocene. In the early Messinian, approximately 7.2 to 6.0 million years ago, the basin received hemipelagic marl deposits that were punctuated by turbidite events. Soles of thin, turbidite sand beds preserve an abundance of pre-depositional graphoglyptid (agrichnial) burrows that represent diverse deep-sea ichnocoenoses, including Paleodictyon, Urohelminthoida and Helminthorhaphe. Post-depositional feeding burrows, including Ophiomorpha (created by crustaceans) and Scolicia (created by echinoids) occur sparsely in some turbidite beds, but they are far out-numbered by the pre-depositional agrichnial burrows. This diverse trace fossil association occurred in a small, short-lived, coastal basin that apparently never got more than a few hundred meters deep. As the basin opened up and flooded in the Late Miocene, the sea floor was colonized rapidly by benthic organisms of uncertain biological affinity, who created a wide variety of anastomosing and meandering tunnels, in which a nourishing food supply (probably bacteria or fungi) apparently grew on mucus-lined walls

Captación y selección de materias primas en la primera metalurgia del Sureste de la península ibérica

El papel de la metalurgia en las comunidades de la Edad del Cobre del Sureste de la península ibérica es una cuestión recurrente en la investigación arqueológica en Europa oc­cidental. A partir del análisis de isótopos de plomo y ele­mentos traza de restos arqueometalúrgicos, este artículo aborda la organización territorial de la producción meta­lúrgica durante la Edad del Cobre (3100-2200 cal aC) en la cuenca de Vera (Almería, España); la región con las primeras evidencias metalúrgicas en Europa Occidental. Este artículo incluye el estudio de materiales de los tres principales asentamientos con actividad metalúrgica en la zona (Las Pilas, Santa Bárbara y Almizaraque), así como algunos objetos metálicos de estos y otros sitios (La Encan­tada I, Loma de Belmonte y Las Churuletas 1). 
 Los resultados sustentan un modelo de producción re­gional a pequeña escala mediante el cual los asentamientos explotaron varios de los recursos de su entorno cercanos (hasta 30 km en línea recta). Se priorizaron las mineraliza­ciones ricas en arsénico y otros elementos, incluso cuando otras fuentes eran más accesibles: para el caso de Las Pilas, la explotación de las fuentes de Pinar de Bédar en lugar de las de Sierra Cabrera, más cercanas al yacimiento; y para los casos de Santa Bárbara y Almizaraque, las fuentes de Cerro Minado. La posibilidad de que tanto Almizaraque como Las Pilas también explotaran los minerales de Herre­rías, aunque en menor medida, permanece abierta. La exis­tencia de redes de intercambio más amplias queda reflejada por los datos de los objetos, a partir de los cuales se puede inferir una mayor movilidad.

Origin of the gypsum veins associated with the diagenetic dolomite nodules from the Neogene Marls of South-East Spain

The late Neogene marls from the Lorca, Murcia and Vera basins in S-E. Spain contain abundant dolomite nodules that were formed due to intense methane-rich fluid migration. The pathways for these fluids are evidenced by dense networks of fractures that are crossing the sedimentary layers and eventually the dolomite nodules. The fractures are generally filled by secondary fibrous gypsum that form veins of a few cm thick.The oxygen and sulfur isotopic compositions of the gypsum veins exhibit wide ranges (−2.2 < δ18O‰ VSMOW <6.7; −22.3 < δ34S‰ VCDT <10.5) that are far away from the average δ values of Tortonian-Messinian gypsum from the basins of Lorca, Fortuna and Sorbas (δ18O = 13.8 ± 2.3‰; δ34S = 21.3 ± 1.0‰) precipitated from the late Neogene seawater sulfate. These low δ values of the gypsum veins clearly indicate their diagenetic origin that would have resulted from sulfide oxidation with 18O-depleted water. The isotopic compositions of the diagenetic dolomite nodules close to the gypsum veins (−0.7 < δ18O‰ VPDB <3.7; −11.9 < δ13C‰ VPDB <7.3) are indicative of their formation in methane-rich fluids. In this context, the formation of sulfide is related to the bacterial sulfate reduction that is associated with the anaerobic oxidation of methane. During this process, pyrite coprecipitated with dolomite, either within the dolomite framework or within conduits where the fluids were seeping. The pyrite oxidation occurred later during diagenesis when more or less oxygenated groundwaters circulated within the fractures during the sealevel drawdown of the Messinian Salinity Crisis and after the regional uplift of the sedimentary deposits in relation with the Betic cordillera tectonics.

Palaeoenvironmental interpretation of the Pliocene fan-delta system of the Vera Basin (SE Spain): Fossil assemblages, ichnology and taphonomy

The marine fossil assemblages of the Pliocene of south Spain constitute the record of the marine fauna that colonised the western part of the Mediterranean after the Messinian Salinity Crisis. This work focuses on the analysis of lithofacies and fossil assemblages including trace fossils, invertebrates, and vertebrates with special attention to taphonomic features, for interpreting palaeoenvironmental conditions in the Vera Basin (SE Spain). The sedimentary sequences of the northern region of the Vera Basin display diverse stratigraphical, sedimentological, and palaeontological features that correspond to the evolution of a fan-delta in a narrow basin. The Vera Basin was characterised by shallow-marine shelf conditions during the early-mid Pliocene (Cuevas Formation). The basin emergence with the development of Gilbert-type fan deltas (Vera Member), and a protected, partially-enclosed marine embayment (Almanzora Member) occurred during the mid-late Pliocene due to regional uplift and movements of the Palomares strike-slip Fault along the eastern basin margin. The progradation of the central fan-delta lobes and the interaction with marginal fan-delta resulted in the partitioning of the basin that formed a small sub-basin with restricted stagnant conditions that favoured a Konservat Fossil-Lagerstätte. The high input of siliciclasts due to the uplift context of the margins of the basin favoured a high sedimentation rate and the fast burial of vertebrate remains. Fossil marine mammals occurs from shallow shelf deposits (Cuevas Formation) to bottomset (Cuevas Formation-Vera Member transition) and lower part of the clinoforms in the foreset (Vera Member). Cetacean remains are usually recorded not only in the relatively deep-water silty marls and sandy marls of the outer shelf and distal facies of the fan-delta (Espiritu Santo Formation), but also in the shallower coarse sands and conglomerates (Cuevas Formation and Espiritu Santo Formation). Sirenian remains, in contrast, are only recorded in coarse sand facies (Cuevas Formation and Espiritu Santo Formation) associated to charcoal wood fragments deposited in shallow waters near the shoreline. This narrow and relatively protected basin is interpreted as an area of reproduction and nursery of juveniles on the basis of the presence of cetaceans.

A new chronostratigraphic and palaeoenvironmental framework for the end of the Messinian salinity crisis in the Sorbas Basin (Betic Cordillera, southern Spain)

New palaeontologic, sedimentologic, and Sr isotope data allow to reconstruct a high‐resolution chronostratigraphic and palaeoenvironmental framework of the continental‐marine transition at the Miocene–Pliocene boundary in the Sorbas Basin (Betic Cordillera, South‐eastern Spain). The presence of Reticulofenestra zancleana, Ceratolithus acutus, and R. pseudoumbilicus in a marine horizon sharply overlying the continental deposits of the Zorreras Member indicates that the Messinian salinity crisis ended in the Sorbas Basin synchronously with the other Mediterranean basins at the base of the Zanclean, within the MNN12a biozone. Our results suggest that the Zanclean flooding turned the Sorbas Basin into a shallow bay with limited exchange with the main Mediterranean basin, probably through narrow seaways connecting also the Almeria, Nijar, and Vera basins. Our results do not confirm previous hypotheses envisaging an older age for the return to fully marine conditions in the Sorbas Basin and is in a good agreement with the reconstructions suggesting that the Zorreras Mb. continental deposits are the local time‐equivalent of the latest Messinian Lago‐Mare phase during the last stage of the salinity crisis.

SEDIMENTOLOGY: The ichnoassemblages of the Abad Member (Tortonian–Messinian), Vera Basin, SE Spain: implications for the regional tectonic and palaeogeographical evolution

AbstractThe Vera Basin is one of a series of interconnected Neogene–Quaternary-age basins located within the Betic Cordillera in SE Spain. The initial marine phase in the basin is represented by the sedimentary succession of the Abad Member (Tortonian–Messinian) and comprises mainly marls with varying amounts of intercalated siliciclastic–calcareous turbidites. The succession contains a rich ichnofauna comprising 12 ichnogenera (21 ichnospecies), which can be subdivided into a number of distinct ichnoassemblages. Detailed analysis of the distribution of these ichnoassemblages reveals that deposition occurred within the Nereites ichnofacies, more specifically, the Paleodictyon sub-ichnofacies, presumably in a lobe-type setting, and at epi- to mesobathyal depths (i.e. 200–1000 m). Changes within the ichnofacies suggest that there is a clear deep-through-to-shallow trend within the succession extending from the older (i.e. Almocáizar Corridor) to the younger (i.e. centre of the Vera Basin) parts of the succession. These changes coincide with the onset of the Messinian Salinity Crisis (MSC) across the region, and correlate well with the pre-MSC through to Lago Mare deposits.

Early metallurgy in SE Iberia. The workshop of Las Pilas (Mojácar, Almería, Spain)

Big narratives on the role of metallurgy in social change and technological innovations are common in archaeology. However, informed discussion of these issues requires a contextualised characterisation of metallurgical technology at the local level in its specific social and technological contexts. This paper approaches early metallurgy in Iberia from a technological perspective. We focus on the site of Las Pilas in the Vera Basin (Mojacar, Almeria, Spain), where the whole metallurgical chaine operatoire has been documented in situ through archaeological excavation of a third millennium bc context. The study includes microstructural, mineralogical and chemical analyses of ores, slag, technical ceramics and finished artefacts, as well as domestic pottery used for comparative purposes. These results are discussed with reference to the archaeological context and evidence for other domestic activities and crafts. Our aim is to contribute to better characterise the early metallurgical tradition of Southeast Iberia, paying particular attention to specific technological tools, knowledge and recipes that may allow future comparative approaches to knowledge transmission or independent innovation debates. For this particular case, we demonstrate the direct production of arsenical copper in a low-scale, low-specialisation, low-efficiency set up that involved the crucible smelting of complex oxidic ores in a context that suggests associations with cereal roasting and, indirectly, with basket and pottery making.

Emplacement of the Cabezo María lamproite volcano (Miocene, SE Spain)

Lamproite volcanoes are uncommon in the geological record but are exceptionally well preserved in the Betic Cordilleras of SE Spain, where they erupted during the Late Miocene (Tortonian to Messinian stages). The parent melts are thought to have been channelled through major lithospheric faults to erupt at or near the faulted margins of Neogene sedimentary basins. Lamproite magmas are thought to be relatively CO2-poor (<1 wt %) and are typically characterised by an effusive eruption style and the development of lava lakes and scoria cones. Cabezo Maria is a relatively small (∼550 m diameter) lamproite volcano that was emplaced within the shallow-water marine-influenced Vera Basin. The lamproites are compositionally similar to those of the Roman Province and generally less potassic (K2O<5 wt%) than other (ultra-) potassic rocks in SE Spain (e.g. Cancarix, Fortuna). The initial eruption stages were dominated by explosive magma-water interactions and the formation of peperites. These are characterised by angular fragments of glassy lamproite lavas (and isolated lobes) incorporated in sediments, locally showing the effects of thermal metamorphism. Further, elutriation pipes and ‘jigsaw-fit’ textures are observed in the peperites. The lavas and peperites are overlain by outward-dipping well-stratified scoria deposits defining part of a cinder cone, which is inferred to have emerged above sea level. Steep internal contacts with inward-dipping, structureless breccias likely represent the inner wall deposits of a central conduit. The deposits are cross-cut by late-stage dykes, which supplied fissure eruptions of geochemically similar lavas capping the scoria cone. The transition from explosive to effusive behaviour may reflect the decreased availability of water, possibly due to downward migration of the feeder conduit below the level of water-saturated sediments.

Anthropogenic and climatic impact on Holocene sediment dynamics in SE Spain: A review

The climatic and anthropogenic control on Holocene sediment dynamics was not well constrained for the Western Mediterranean basin. The paucity of high resolution palaeoenvironmental records long hampered a detailed understanding of the human impact on erosion rates. This paper analyses Holocene sediment dynamics in the context of regional climatic conditions, land cover and human occupation based on an extended compilation of recently published high-resolution paleoenvironmental proxy data from both terrestrial and marine environments. The palaeoenvironmental reconstruction identified four main aridification episodes (A) at 5600–4700 (A4), 4100–3400 (A3), 2800–2500 (A2), and 1900–1300/1200 (A1) cal. BP. Most of the severe aridification phases were climatically induced, not human-driven and well correlated with a large dataset of paleoenvironmental records from the Western Mediterranean Basin and North Atlantic Ocean. The phases of enhanced aridity are generally associated with enhanced sediment dynamics, independent of the intensity and type of human occupation. In contrast, wet climatic conditions are found to be associated with both high and low sediment dynamics dependent on the human impact on the environment. The mid-late Phoenician, Phoenician II/Republican Rome civilizations and the Christian Reconquest are all associated with high human impact on the environment, and high erosion rates are reported for the Vera basin and NE Spain despite the improved hydrological conditions. Human occupation is not necessarily associated with geomorphic instability, as shown by the Post Argaric, Omeya and Nazarene periods that are characterized by low erosion rates and geomorphic stability.

Mountain front migration and drainage captures related to fault segment linkage and growth: The Polopos transpressive fault zone (southeastern Betics, SE Spain)

The Polopos E–W- to ESE–WNW-oriented dextral-reverse fault zone is formed by the North Alhamilla reverse fault and the North and South Gafarillos dextral faults. It is a conjugate fault system of the sinistral NNE–SSW Palomares fault zone, active from the late most Tortonian (≈7 Ma) up to the late Pleistocene (≥70 ky) in the southeastern Betics. The helicoidal geometry of the fault zone permits to shift SE-directed movement along the South Cabrera reverse fault to NW-directed shortening along the North Alhamilla reverse fault via vertical Gafarillos fault segments, in between. Since the Messinian, fault activity migrated southwards forming the South Gafarillos fault and displacing the active fault-related mountain-front from the north to the south of Sierra de Polopos; whilst recent activity of the North Alhamilla reverse fault migrated westwards. The Polopos fault zone determined the differential uplift between the Sierra Alhamilla and the Tabernas-Sorbas basin promoting the middle Pleistocene capture that occurred in the southern margin of the Sorbas basin. Continued tectonic uplift of the Sierra Alhamilla-Polopos and Cabrera anticlinoria and local subsidence associated to the Palomares fault zone in the Vera basin promoted the headward erosion of the Aguas river drainage that captured the Sorbas basin during the late Pleistocene.

Plio-Pleistocene drainage development in an inverted sedimentary basin: Vera basin, Betic Cordillera, SE Spain

The Vera basin is one of a series of interconnected Neogene–Quaternary sedimentary basins located within the Internal Zone of the Betic Cordillera (southeast Spain). Since the Pliocene the Vera basin has been subjected to low uplift rates (11–21 m Ma − 1 ) and inverted via compressive tectonics that are related to the ongoing oblique collision between the African and Iberian plates. Within this paper the sedimentary and geomorphic response to basin inversion is explored. Sedimentary processes and environments are established for key stratigraphic units of the Pliocene/Plio-Pleistocene basin fill and Pleistocene dissectional landscape. These data are subsequently utilised to reconstruct an evolving basin palaeogeography. Fault and uplift data are employed to discuss the role of tectonically driven basin inversion for controlling the resultant palaeogeographic changes and associated patterns of drainage development. During the Early-Mid Pliocene the Vera basin was characterised by shallow marine shelf conditions (Cuevas Formation). A major palaeogeographic reorganisation occurred during the Mid-Late Pliocene. Strike-slip movement along the eastern basin margin, coupled with uplift and basin emergence created a protected, partially enclosed marine embayment that was conducive for Gilbert-type fan-delta sedimentation from fluvial inputs along the northern and eastern basin margins (Espíritu Santo Formation). The Vera basin then became fully continental and internally drained through the development of a consequent drainage network that formed following the withdrawal of marine conditions during the Late Pliocene to Early Pleistocene. Alluvial fans developed along the northern and western basin margins, grading to a bajada and terminating in a playa lake in central basin areas (Salmerón Formation). During the Early-Mid Pleistocene a switch from basin infilling to dissection took place, recorded by alluvial fan incision, a switch to braided river sedimentation and fluvial incision into the underlying basin fill sediments and basin margin mountainous topography. Fluvial incision, headwards erosion, expansion and modification of the consequent drainage network is documented within a series of up to four major inset river terrace levels and associated landforms. Fluvial incision and drainage network expansion are attributed to differential uplift and the creation of regional gradients between adjacent basins. The relatively low Plio-Pleistocene uplift rate of the Vera basin (11–21 m Ma − 1 ) in comparison to adjacent basins (Sorbas: 80–160 m Ma − 1 ; Huercal–Overa: > 50 m Ma − 1 ) resulted in a switch from internal to external basin drainage. Ancestral forms of the principal drainage systems within the Vera basin: the Ríos Almanzora, Aguas and Antas, captured basins and mountain catchment areas to the north (Huercal–Overa basin), southwest (Sorbas basin) and west (Sierra de los Filabres range). The switch from basin infilling to fluvial dissection is coincident with a phase of Early-Mid Pleistocene compressional tectonics, expressed by extensional faulting. This deformation is probably linked to accelerated strike-slip movement along the Palomares Fault Zone. The faulting is superimposed onto the longer term pattern of Plio-Pleistocene uplift and basin inversion.

Neogene tectonic evolution of the Gibraltar Arc: New paleomagnetic constrains from the Betic chain

New paleomagnetic results from Neogene sedimentary sequences from the Betic chain (Spain) are here presented. Sedimentary basins located in different areas were selected in order to obtain paleomagnetic data from structural domains that experienced different tectonic evolution during the Neogene. Whereas no rotations have been evidenced in the Late Tortonian sediments in the Guadalquivir foreland basin, clockwise vertical axis rotations have been measured in sedimentary basins located in the central part of the Betics: the Aquitanian to Messinian sediments in the Alcalà la Real basin and the Tortonian and Messinian sediments in the Granada basin. Moreover, counterclockwise vertical axis rotations, associated to left lateral strike-slip faults have been locally measured from sedimetary basins in the eastern Betics: the Middle Miocene to Lower Pliocene sites from the Lorca and Vera basins and, locally, the Tortonian units of the Huercal-Overa basin. Our results show that, conversely from what was believed up to now, paleomagnetic rotations continued in the Betics after Late Miocene, enhancing the role of vertical axis rotations in the recent tectonic evolution of the Gibraltar Arc.

Calcrete ‘fossilisation’ of alluvial fans in SE Spain: The roles of groundwater, pedogenic processes and fan dynamics in calcrete development

Dryland alluvial fans developed along the northern flanks of the Sierra Lisbona in the north-western Vera basin (Almería region, southeast Spain) display negligible amounts of incision despite distal base-level lowering of > 30 m by the modern drainage network. The fans are of early-middle Quaternary age and are graded to a coeval river terrace, now isolated from the modern drainage network. The negligible incision is due to the encasement and ‘fossilisation’ of the alluvial fans by calcrete. This paper explores the reasons for such fossilisation and assesses the relative importance of pedogenic and groundwater mechanisms for calcrete formation within an alluvial fan setting. A single fan was selected for detailed examination. The geomorphological and sedimentological features of the fan, its catchment area and their relationship to the distal river terrace were documented. Qualitative and semi-quantitative petrographic and scanning electron microscope analyses of calcrete samples collected from transects across the fan surface, and within its distal top river terrace surface, enabled the style, pattern and relative timing of calcrete development to be assessed. Calcrete fabrics comprised initial micritic grain-coating cements, pellets and glaebular carbonate nodules, with interstitial spaces infilled by equant sparite and microsparite mosaics. It is proposed that the early phases of calcrete development were dominated by pedogenic processes with increasing groundwater calcretisation over time. Point count data indicated increased quantities of interstitial sparite and microsparite cement within near-surface proximal fan calcretes and at depth across the fan, suggesting that groundwater processes played a more important role in calcrete formation in these locations. The contribution of groundwater to calcrete development can be best explained by the intrinsic funnelling of groundwater from the catchment through the proximal fan head area, a zone where the fan gravels are thinnest. Calcrete ‘fossilisation’ appears to have followed a reduction in the fan catchment area as a result of rockfalls and watershed stream capture, which reduced water and sediment supply to the fan and enabled surface stabilization and calcrete development to take place. The reduced sediment/water supply, combined with calcrete fossilisation, appears to have protected the alluvial fans from regional base-level lowering. The implications of these results for existing pedostratigraphic models of calcrete development in alluvial fans are subsequently explored.

Testing models for the Messinian salinity crisis: The Messinian record in Almería, SE Spain

Neogene intermontane basins in Almería Province, SE Spain, display excellent exposures of Messinian (Late Miocene) sequences. The Sorbas, Almería-Níjar and Vera basins maintained connection with the Mediterranean throughout the Messinian, except during the major desiccation phase leading to the formation of salt in the deep centre of the Western Mediterranean. These basins were part of the Western Mediterranean with no separate link to the Atlantic Ocean. The presence of normal marine sediments in these basins reflects the Western Mediterranean watermass. Messinian pre-evaporitic sediments in the basins of southeastern Almería do not show gradual change towards evaporite deposits. Instead they contain stenohaline invertebrates right up to a major erosion surface that separates them from overlying gypsum deposits. This contradicts suggestion of progressive salinity increase in this part of the Western Mediterranean prior to the Messinian Salinity Crisis (MSC); it also indicates that initiation of evaporite precipitation was not synchronous throughout the Mediterranean Basin. There is no major erosion surface within or at the top of the evaporites in these Almería basins, and the gypsum beds exhibit upward transition to siliciclastic and carbonate deposits. This is inconsistent with a model of Messinian Mediterranean evaporite formation whereby deposition of marginal evaporites was followed by their erosion during drawdown that resulted in formation of evaporites in the centre of the Western Mediterranean. The presence of stenohaline biotas in siliciclastic deposits interbedded with the gypsum and in the Messinian post-evaporitic sediments, challenges the view that a long-standing large body of brackish water (the Lago Mare) filled the Western Mediterranean following the MSC and prior to Early Pliocene flooding. It also contradicts the concept of many relatively small brackish basins spread across an otherwise desiccated Western Mediterranean basin. The basins of southeastern Almería record normal marine Early Messinian sedimentation that was abruptly interrupted by sealevel fall. This drawdown most likely resulted in precipitation of evaporites in the central deep Western Mediterranean basin. Following this episode, final marine reflooding of the Western Mediterranean took place during the Late Messinian, and the Mediterranean Sea rose to a level similar to, or higher than, that preceding the Salinity Crisis.

The Neolithic in Almeria: the valley of Almanzora river in Vera basin

The valley of Almanzora River and Vera Basin (Almeria) shows an intense dynamics of occupation in Prehistory; particulalry between the Early Neolithic and the Late Bronze Age. Several factors, such as recurrent associations betwen diverse productions - including the presence of cardial-impresed in Cabacicos Negros (Vera) - and the distinctive characteristics of the type of accupation, indicate that the oldest phase of occupation took place during the andalusian Early Neolithic. The socio-economic pattern is defined both by expoloatation of numerous resources in an area of variable size, and by the temporary occupation of settlements, with seasonal or periodical variations. The constant mobility was aimed at obtaining different subiststence goods, as well as obtaining and/or transforming primary resources for manufacturing crafts and exchanging excess production with communities in the same area or from other regions.

Uppermost Tortonian to Quaternary depocentre migration related with segmentation of the strike-slip Palomares Fault Zone, Vera Basin (SE Spain)

The Palomares Fault Zone (PFZ) is one of the main strike-slip brittle shear zones found in the Betics. It is segmented in several faults that have been active between the Upper Tortonian and present day. Data from drill cores in the Palomares area have permitted us to define the geometry and location of sedimentary depocentres related with the PFZ. These data show an eastward displacement between the Upper Tortonian to Messinian and the Pliocene–Quaternary sedimentary depocentres, towards the presently active Arteal fault, which bounds the western mountain front of Sierra Almagrera, showing that deformation along this fault zone has migrated towards the east, from the Palomares segment, with its main activity during the Upper Tortonian and Messinian, towards the Arteal fault, active during the Pliocene and Quaternary. To cite this article: G. Booth-Rea et al.,

The Messinian of the Nijar Basin (SE Spain): sedimentation, depositional environments and paleogeographic evolution

The reconstruction of the depositional events related to the Messinian Salinity Crisis (MSC) of the Mediterranean is generally hampered by an incomplete stratal record in the circum-Mediterranean basins. The sediments of the northern part of the Nijar Basin, however, provide an excellent and continuous record of Late Messinian sediments because features of severe erosion are lacking. Especially, the successions of the deeper part of the basin had sufficient accommodation space to warrant ongoing deposition and may thus serve as a testing ground for existing hypotheses regarding the MSC. Conformable contacts with the overlying Pliocene and good correlation possibilities with the adjacent, astronomically dated, Messinian of the Sorbas Basin provide the necessary age constraints. The main body of evaporites in the Nijar Basin (Yesares Formation) has been affected by local dissolution and erosion prior to deposition of the latest Messinian (Lago–Mare) facies. Pelitic float breccias show textures indicating flowage and/or mass transport and include slumped and slided stratal packets due to foundering of the mixed evaporitic–clastic margin. Increased runoff of meteoric waters probably played an important role as these packet slides are perfectly sealed by the hyposaline Lago–Mare strata. Field observations show that marginal sediments, commonly classified as the Terminal Carbonate Complex (TCC), are a lateral equivalent of the basinal Yesares evaporites. The latest Messinian deposits (Feos Formation) are characterized by a sedimentary cyclicity, related to fluctuating base levels, consisting of chalky–marly laminitic strata alternating with continental coarser clastic intervals. Despite considerable W–E facies changes and indications for discrete tectonic events, a persistent sequential pattern of eight Lago–Mare cycles is present, which are interpreted as precession-controlled variations in regional climate. Instead of one major desiccation event in the latest Messinian, the repeatedly fluctuating water levels of the Lago–Mare episode may have been the cause of the widespread vigorous erosion and canyon cutting in the “Lower Evaporites”. Abrupt, non-erosional contacts with the normal marine Pliocene take place above the continental interval of the last Lago–Mare cycle, indicating that flooding took place during a period of lowered water levels. The paleogeographic configuration of the Nijar, Sorbas and Vera basins has changed considerably during the Messinian. Separation of the formerly interconnected basins is thought to have started in the late Yesares times by tectonic uplift of the basement complexes. In the latest Messinian of the Nijar Basin, two different coarse clastic supply areas can be distinguished which point to the partial emergence of the Sierra Cabrera and the Cabo de Gata block and activity of the Sierra Alhamilla and Carboneras faults. Concerning the overall regional tectonic activity, tectonics were probably also instrumental for the restoration of the Atlantic gateway in the basal Pliocene.