Sierra De Los Filabres Research Articles

The provenance of a turbidite system within a tectonically active wrench basin: Insights from heavy mineral characteristics of Miocene sandstones in the Tabernas Basin, south‐east Spain

AbstractThis paper provides insight into the provenance of the Late Miocene turbidite succession of the Tabernas Basin. Although this area has been extensively studied, only limited attention has been paid to sediment provenance. Through heavy mineral analysis, it has been possible to identify provenance‐related signatures from the adjacent Sierra de los Filabres and Sierra Alhamilla uplifts. Stable mineral ratio data confirm that the Sierra de los Filabres provided sediment with generally higher chloritoid:tourmaline and higher Type Bii garnet abundances than those derived from the Sierra Alhamilla. By comparison, modern sediments derived from the Sierra Alhamilla have garnet compositions with larger proportions of Types A and C, suggesting that the basinal sediments were not sourced from the incipient Sierra Alhamilla Uplift. Heavy mineral analysis confirms that the Sierra de los Filabres was the primary source for the Tabernas succession, with minor variations indicating that the erosive part of the system migrated across the uplift. Input was predominantly from the Nevado–Filábride Complex, with minor amounts from the small remnant of the Alpujarride Complex attached to the southern margin of the Sierra de los Filabres. Evidence strongly suggests a single sediment routing system but identifies some subtle provenance variations. In particular, there was a shift in detrital garnet composition between the Sartenella Formation and the Verdelecho Formation, Solitary Channel and El Gordo Megabed, which is attributed here to a shift in catchment within the Sierra de los Filabres. This shift appears to have occurred during the deposition of the Sartenella Formation, since the garnet compositions of the Verdelecho Formation and Solitary Channel are similar to each other and differ from the preceding part of the Sartenella Formation. The Solitary Channel displays marked heterogeneities in provenance character, manifested by changes in chloritoid abundance, consistent with previous studies that suggest the depositional architecture in the channel was influenced by high‐frequency changes in sediment flux and sea level.

Early Mylonitization in the Nevado-Filábride Complex (Betic Cordillera) during the High-Pressure Episode: Petrological, Geochemical and Thermobarometric Data

In the western part of the Sierra de los Filabres area, there are fine-grained metamorphic rock bands, showing a field aspect simitar to slates, as previously described in the geological literature of the studied region. They are variable in thickness, from millimeters to tens of meters and appear intercalated in the schist succession. The geochemical resemblance between both types of rocks (major, minor and trace elements), determined by a statistical approach and the comparison of depositional condition indices, points to a similar sedimentary origin of the protolith but different clay content. Mineral facies and illite “crystallinity” indices in the so-called slates indicate that they followed the same metamorphic path and reached the same metamorphic grade than schists. According to compositional zoning detected in micas and garnets present in both lithologies and the P-T conditions deduced from garnets, the mineral nucleation and growth episode of the main mineral paragenesis in these fine-grained schists was more remarkable during the high-pressure event, with a no significant effect of the latter low-pressure–high-temperature episode. In contrast, the coarse-grained schists developed higher size minerals during the low-pressure–high-temperature episode. A differential mylonitization process during the metamorphism is proposed to justify the discrepant field appearance and the contrasting response of both types of metapelitic rocks to the latter metamorphic event.

Carex camposii subsp. tejedensis (Cyperaceae), a new taxon for Southern Iberian Peninsula based on molecular, morphological and ecological differentiation.

Carex camposii Boiss. & Reut., endemic to high mountain ranges in Southern Iberian Peninsula (Sierra Nevada, Sierra de los Filabres and Sierra de Baza), is a morphologically and molecularly well-defined species included in Carex gr. laevigata (subg. Carex, sect. Spirostachyae). We have discovered a population of a morphologically similar species to C. camposii in a different mountain range (Sierra de Tejeda), that displayed some deviant morphological characters and was found in a different habitat from that typical of the species. In order to disentangle the taxonomic status of this population, we have conducted a phylogenetic analysis using five nuclear (ITS, ETS, G3PDH, CATP and GZF) and three plastid (matK, rpS16 and 5’trnK intron) DNA regions. In addition, a morphological analysis including the population from Sierra de Tejeda was carried out. The resulting phylogenetic trees show that the samples of the problematic population are closely related to C. camposii, while the morphological study revealed that a total of nine morphological features did not match those of typical C. camposii. Even though the samples from Sierra de Tejeda are genetically not well differentiated from C. camposii, the morphological and ecological differentiation supports its recognition as a new subspecies, C. camposii subsp. tejedensis. An assessment of its conservation status using IUCN categories and criteria suggests that it could be critically endangered (CR).

Lithostratigraphy and structure of the Macael marbles (Betic zone, Spain)

A complex stack of tectonic imbricates is mapped and studied in the Nevado-Filábride Complex of the Macael-Cóbdar area of the Sierra de los Filabres. The lithostratigraphy and geological structure are unravelled, documenting key outcrops in the heavily quarried area that is famous for its pure white marble. Four principal successive stages of deformation are recognized, based on careful field work. Initial SW-verging folding and thrusting was followed by extensional, top-to-the-NW shearing. Late N-verging folding and thrusting is also prominent. The resulting lithostratigraphic and tectonic subdivision is compared with some of the previous investigations in the area, which span over 6 decades. The findings assert the importance of using detailed local field data and the difficulty to apply a simple stratigraphic or tectonic model for this part of the Betic Zone.

Natural occurrence of asbestos in serpentinite quarries from Southern Spain.

The nevado-filábride complex (NFC) (southern Spain) is well known for its widespread mining and quarrying activities. Serpentinite and metabasite rocks are extracted, processed and traded as building and ornamental stones. Due to the possible presence of natural occurrence of asbestos (NOA) in these rocks, the aim of this paper is to conduct an in-depth characterisation of fibrous minerals. To this aim, seven serpentinite rock samples were collected in four quarries located in the Sierra Nevada and Sierra de los Filabres (South-eastern Spain), which were then analysed by X-ray powder diffraction (XRPD), scanning electron microscopy combined with energy-dispersive spectrometry (SEM/EDS), differential scanning calorimetry (DSC), derivative thermogravimetry (DTG) and X-ray synchrotron microtomography (SR-µCT). It is essential to investigate asbestos minerals from both scientific and legal perspective, especially for public health officials that implement occupational health and safety policies, in order to safeguard the health of workers (e.g. quarry excavations, road yards, civil constructions, building stones).

Influence of natural carbonation process in serpentinites used as construction and building materials

Serpentinites are rocks commonly used in construction. They have a very complex origin and multiple factors can influence their behaviour once placed in a building. These include the carbonation process that occurs naturally in these rocks. This process causes transformations of the serpentinite minerals (hydrated magnesium silicates) into carbonates, which affect their properties as building material. In the south of Spain, serpentinites have traditionally been used from two areas: Sierra Nevada (Granada), starting from the thirteenth century and the Sierra de los Filabres (Almeria). More recently, the latter are extracted together with the “White Macael” marble. They show variable carbonation state which is reflected in different properties even between very close outcrops. Their mineralogy, geochemical composition, and main technological characteristics were determined in accordance with the different UNE-EN Standards for use in the building industry. According to the results obtained, the process of carbonation in serpentinites affects their properties for construction and building materials. This process produces increased bulk density and decreased water accessible porosity, water absorption under atmospheric pressure, and water absorption coefficient by capillarity. Carbonation also leads to increased velocity of ultrasonic p-waves. The uniaxial compressive strength displays low values compared with the other samples. The values obtained for flexural strength are similar, or slightly lower, compared to the non-carbonated serpentinite. Knoop microhardness increases with carbonation. The results of our study can improve efficiency, productivity, and competitiveness in the use of serpentinites in the building industry.

3D geometry of superposed folds in a large-scale refolded fault surface using geostatistical methods (internal zones of the Betic Cordillera, SE Spain)

In this work, we restore the folded and partly eroded surface of the Mecina Fault in the internal zones of the Betic Cordillera. The main aim of this restoration is to analyze the geometry of the folds of Sierra Nevada, Sierra de los Filabres and the southern branch of the Guadix-Baza Basin. The restoration was made in an ArcGIS environment using the kriging geostatistical method, allowing the building of an accurate digital surface model (DSM), as the estimation errors are low. The DSM and field measures provided the orientation data used in the geometrical analysis of the structures by standard structural geology methods. The results indicate the superposition between two generations of folds, resulting in a pattern that combines domes and basins and non-plane non-cylindrical folds with hinge replacement. These two generations of folds were forming during the Tortonian (first generation) and the Pliocene (second generation) according to previous works of sedimentology and thermochronology.

Growth decline assessment in Pinus sylvestris L. and Pinus nigra Arnold. forest by using 3-PG model.

Aim of the study: We assessed the ability of the 3-PG process-based model to accurately predict growth of Pinus sylvestris and P. nigra plantations across a range of sites, showing declining growth trends, in southern Spain.Area of study: The study area is located in “Sierra de Los Filabres” (Almería).Material and methods: The model was modified in fifteen parameters to predict diameter (DBH, cm), basal area increment (BAI, cm2 yr-1) and leaf area index (LAI, m2 m-2) in healthy trees and trees showing declining growth. We assumed that a set of specific physiological parameters (stem partitioning ratio-pFS20, maximum litterfall rate-γFx, maximum canopy conductance-gCx, specific leaf area for mature aged stands-σ1, age at which specific leaf area = ½ (σ0 + σ1), age at full canopy cover-tc, and canopy boundary layer conductance-gB) included in 3-PG would be suitable for predicting growth decline related to climate conditions. The calibrated model was evaluated using dendrochronological and LAI data obtained from plots.Main results: Observed and simulated DBH showed a high correlation (R2 > 0.99) between modelled and measured values for both species. In contrast, modelled and observed BAI showed lower correlation (R2 < 0.68). Sensitivity analysis on 3-PG outputs showed that the foliage parameters - maximum litterfall rate, maximum canopy conductance, specific leaf area for mature aged stands, age at which specific leaf area, and age at full canopy cover - were important for DBH and BAI predictions under drought stress.Research highlights: Our overall results indicated that the 3-PG model could predict growth response of pine plantations to climatic stress with desirable accuracy in southern Spain by using readily available soil and climatic data with physiological parameters derived from experiments.Keywords: Hybrid process model; forest management models; growth prediction; Pinus spp, Parameterization; forest decline.

The nevado-filábride complex in the western part of Sierra de los Filabres (Betic Internal Zone), structure and lithologic succession

In the western part of Sierra de los Filabres (in the Nevado-Filábride Complex, within the Betic Internal Zone) several tectonic units have been described, in varying numbers depending on the author describing them. However, new cartographical data show that the limits of these units pass through the lithological formations without displacing them. Moreover, the rocks belonging to some units that are supposedly situated in a lower tectonic position really belong to higher formations. From bottom to top, these lithological formations are the following: (1) dark schists and quartzites; (2) quartzites, sandstones, sands, lutites, schists, and mica schists; (3) schists; (4) marbles, schists, and mica schists. High-angle reverse faults are associated with the great E-W anticline of Sierra de los Filabres. The existence of sands and apparent lutites visibly interlayered between rocks, such as schists and mica schists with garnets, poses a metamorphic problem that has not as yet been addressed.

Active shallow extension in central and eastern Betic Cordillera from CGPS data

The Betic Cordillera is an Alpine belt formed in the western Mediterranean by the westward displacement of the Alboran Domain in between the Eurasian and African convergent plates. New CGPS data from the central and eastern Betic Cordillera and its foreland—obtained mainly from the Topo-Iberia project—allowed us to precisely determine the rate of tectonic deformation. Most of the displacements of the central and eastern Betics are westward, with a variable southwestward component, in relation to the Eurasian stable plate. While in the Iberian foreland the displacements are extremely low, some deformation related to low compressional deformation occurs in the easternmost foreland basin and eastern Betic Cordillera. The displacement increases substantially southwards and westwards in relation to present-day extensional deformation. Major active discontinuities correspond to the NW–SE normal fault zones, which dip westwards; they are located in Almeria–Tabernas; Balanegra, and western Sierra de Gador; whereas the Padul fault zone located west of Sierra Nevada extends northwards to the Granada Basin. NW–SE extensional faults are also observed to the north, in the Baza Basin. Moreover, the activity of dextral faults along the Sorbas–Tabernas–Alpujarras–Guajares band, generally considered as a transfer fault zone, is evidenced by the displacement data. These results come to demonstrate the low activity or inactivity of the large northern E–W oriented folds of the central and eastern Internal Zone, such as the Sierra de Los Filabres antiform. They also point to the possible residual activity of the northern part of the NE–SW Sierra Nevada antiform, where the maximum relief of the Cordillera is found. Altogether, our data support a heterogeneous present-day westward extension that affects the upper crust of the Betic Cordillera and increases towards the thinned continental crust of the Alboran Sea and towards the west, which is compatible with roll-back subduction along the Gibraltar Arc.

The availability of mineral nitrogen in Mediterranean open steppe dominated by Stipa tenacissima L.

The area of interest is located in the Sierra de los Filabres in semi-arid steppe of the province of Almeria in Spain. The amount of water in the soil is a limiting factor and its availability affects the structure and species composition of ecosystem. On the other hand, the type of vegetation affects the water loss via evapotranspiration and thus the soil microclimate. It has a great influence on the growth and activity of soil microbial communities and hence the dynamics of decomposition of organic matter and nutrient availability. The aim of this study was to assess the intensity of microbial transformations of soil organic nitrogen and describe changes in the content of nitrogen mineral forms at different depths in the semi-arid climate soil in the Mediterranean region. Availability and movement of nitrogen was monitored by capturing the mineral nitrogen into the structures of ion exchange resin applied to the soil in three different variants (control variant, a variant with the addition of cellulose, and the variant with the addition of raw silk). Ion exchange resins have been installed into soil profile in 2008, 2009, and 2010. After the in situ exposure the ion exchange resins were removed from the soil profile and the quantity of captured mineral N was determined by distillation titration method. The availability of ammonia-nitrogen was significantly affected by the addition of different substrates mainly by the additions of the raw silk, where the availability was regularly the highest. However, the availability of ammonia-nitrogen form was generally higher than the availability of nitrate form.

From ductile to brittle, late- to post-orogenic evolution of the Betic Cordillera: Structural insights from the northeastern Internal zones

Abstract Relations between Alpine detachment-bounded metamorphic domes, crustal-scale strike-slip fault zones and sedimentary basins in the Internal zones of the Betic cordillera are still matter of debate. Current tectonic interpretations of these basins vary from late-orogenic extensional structures to compressional ones associated with strike-slip motions along major still active faults. Structural investigations including new field mapping, meso-scale faults recognition, palaeostress analysis of brittle small-scale faults systems were performed in the sedimentary cover of the Almanzora corridor and the Huércal-Overa basins, located either in the hanging wall unit of the Filabres extensional shear zone or at the termination of the Alhama de Murcia sinistral fault zone. In parallel, a detailed study of the ductile and the ductile-brittle deformation was carried out in the footwall unit of the Filabres extensional shear zone, in the Nevado-Fílabride complex. Three main brittle events were recognised in the basin cover including two extensional events that occurred prior to a weak tectonic inversion of the basin during a third, still active event. The first one, D1b is characterized by the development a first stress regime consistent with ~NW-SE extensional tectonics. Besides, the consistency between the latest ductile and the brittle kinematics for the Filabres extensional shear zone and the activity of meso-scale fault systems that primarily control the main SW-NE depocentres allow concluding to a top-to-the-NW continuum of strain during the final exhumation of the Nevado-Filábride complex. The resulting overall half-graben architecture of the basins is then related to the combination of the formation of the metamorphic domes that added a local control superimposed on the regional deformation. Indeed, after a consistent top-to-the-west shearing prevailing during most of the Nevado-Filábride exhumation, final exhumation stages were in turn, characterised by important kinematics changes with a subordinate top-to-the-NW sense of shear (D1b). The onset of sedimentation in the basins occurred shortly after the crossing of the ductile-brittle transition in the underlying metamorphic domes at ca. 14 Ma into SW-NE fault-bounded troughs. Tectonic subsidence was then maintained during D2b while extensional kinematics changed to N-S or even locally to SSW-NNE. Extensional tectonics then lasted most of the Tortonian during the final tectonic denudation increments of the Sierra de los Filabres achieved at ca. 9-8 Ma. Intramontane basins are therefore genuinely extensional and clearly related to the latest exhumation stages of the Nevado-Filábride complex in the back-arc domain. Conversely, at ca. 8 Ma, basins started to record a ~N-S to NNW-SSE compressional stress regime (D3b) and ceased to be active depocentres while shortening within the Internal zones then recorded only the Iberia/Africa convergence. The weak inversion of the basins however resulted either in the reactivation of originally extensional faults such as the Alhama de Murcia fault or the basin individualisation and a progressive water exchange reduction with the Atlantic ocean and is thus proposed to be directly responsible for the Late Miocene salinity crises.

Spatial variability and change in soil organic carbon stocks in response to recovery following land abandonment and erosion in mountainous drylands

AbstractThis research investigates the impact of human activities on carbon (C) dynamics in a mountainous and semi‐arid environment. Despite the low C status of drylands, soil organic carbon (SOC) is the largest C pool in these systems and therefore may offer significant C sequestration potential in systems recovering from degradation. Nevertheless, quantification of this potential is limited by lack of knowledge concerning the magnitude of and controls on regional SOC stocks. Therefore, this study aimed to (i) investigate the variability of soil organic carbon in relation to recovery period and key soil and topographical variables, and (ii) quantify the effects of recovery period following abandonment on SOC stocks. Soil profiles were sampled in the Sierra de los Filabres (southeast Spain) in different land units along geomorphic and degradation gradients. SOC contents were modelled using recovery period and soil and topographical variables. Sample depth, topographic position, altitude, recovery period and stone content were identified as the main factors for predicting SOC concentrations. SOC stocks in 1 m depth of soil varied between 3.16 and 76.44 t/ha. Recovery period (years since abandonment), topographic position and altitude were used to predict and map SOC stocks in the top 0.2 m. The results show that C accumulates rapidly during the first 10–50 yr following abandonment; thereafter, the stocks evolve towards a steady‐state level. The erosion zones in the study area demonstrate greater potential to increase their SOC stocks when abandoned. Deposition zones have greater SOC values, although their C accumulation rate is lower compared with erosional landscapes in the first 10–50 yr following abandonment. Therefore, full understanding of the C sequestration potential of land use change in areas of complex topography requires knowledge of spatial variability in soil properties and in particular SOC.

Deciphering tectonic‐ and erosion‐driven exhumation of the Nevado–Filábride Complex (Betic Cordillera, Southern Spain) by low temperature thermochronology

Terra Nova, 23, 257–263, 2011AbstractNew apatite (U‐Th)/He and fission‐track data from the Nevado–Filábride complex in the Sierra Nevada of southern Spain are used to constrain the Neogene exhumation history. Apatite (U‐Th)/He ages are close to fission‐track ages in western Sierra Nevada indicating that rapid cooling occurred at 8–6 Ma, consistent with exhumation due to extension along the Mecina Fault. The western Sierra de los Filabres cooled rapidly at c. 12 Ma, while the central Sierra de los Filabres experienced less rapid cooling at 8 Ma. The age distribution in the Sierra de los Filabres can be explained by exhumation due to flexural uplift to the south‐west of the footwall of the Mecina Fault. The lower cooling rates in the central Sierra de los Filabres suggest that folding and erosion were the main exhumation processes during the Late Tortonian.Terra Nova, 00, 1–7, 2011

Medidas educativas y organizativas de atención a la diversidad que mejoran el rendimiento escolar en el IES Sierra de los Filabres de Serón (Almería)

Este artículo pretende demostrar cómo a través de la adopción de medidas educativas y organizativas adecuadas, seleccionadas y bien planificadas, se puede influir positivamente sobre el rendimiento escolar del alumnado en la Enseñanza Secundaria Obligatoria. La experiencia ha sido realizada en el IES Sierra de los Filabres de la localidad almeriense de Serón, durante los cursos académicos 2008-2009 y 2009-2010. El punto de partida fueron los datos obtenidos del Sistema de Gestión de Centros (Séneca), para el curso escolar 2007-2008, sobre promoción, titulación y rendimiento escolar en las materias instrumentales de lengua, matemáticas e inglés. El equipo directivo del centro decidió, al amparo de la nueva ley aprobada sobre atención a la diversidad (Orden de 25 de Julio de 2008), aplicar una serie de medidas organizativas con intención de estudiar su influencia sobre la mejora en el rendimiento escolar del alumnado, para lo cual se estableció un horizonte de dos cursos escolares. El siguiente trabajo, por tanto, recoge cómo se realizó la experiencia y los resultados que se obtuvieron.

Crustal‐scale transcurrent fault development in a weak‐layered crust from an integrated geophysical research: Carboneras Fault Zone, eastern Betic Cordillera, Spain

New magnetotelluric and receiver transfer function studies provide insights from the upper to the lower crust of the eastern Betic Cordillera, which is deformed by large folds, normal faults, and a major transcurrent left‐lateral fault, the Carboneras Fault Zone (CFZ). Receiver function analysis determines a NNW dipping Moho reaching 20° that increases in depth, from 20 km south of the CFZ up to 34 km in the Sierra de Los Filabres. In addition, seismic discontinuities determined in the upper crust are interpreted as major contacts between metamorphic complexes that are detached and folded. The MT inversion model reveals a conductive zone, also representing a crustal seismic discontinuity, associated with the Alpujárride/Nevado‐Filábride contact and fitting the N vergent geometry of the Sierra Alhamilla antiform. A small flexure at Moho coincides with the CFZ, as revealed by the Bouguer anomaly trend, in agreement with the receiver function results. Moreover, the Bahr strike and tipper angle at the stations placed closest to the CFZ clearly reveal the continuity of the CFZ at least down to approximately 15 km in depth, crossing all the detected crustal discontinuities up to the Moho. The lack of a clear Moho offset associated with the Carboneras Fault supports the idea that some large strike‐slip faults tend to accommodate the deformation by a broadening fault zone at lower crustal levels. Its nucleation could occur at the base of a thin crust, where melting processes critically reduced the lithospheric strength during the late Miocene, to then propagate upward, reaching the topographic surface. Northward, the lithosphere comprised moderately larger strength, and the crustal discontinuities favored the development of larger folds with kilometric amplitude instead of strike‐slip faults since the late Miocene.

Drought-induced growth decline of Aleppo and maritime pine forests in south-eastern Spain.

Climate warming may enhance the negative effects of droughts on radial growth in areas with severe water deficit, such as Mediterranean mountains under semi-arid conditions. The impacts of drought on growth decline of Mediterranean pines have not been evaluated considering species with different vulnerability and areas with contrasting climates. Dendrochronological methods were used to assess the responses of basal area increment to drought in Pinus pinaster and P. halepensis plantations. We compared growth trends of trees with different defoliation degree in two sites in south-eastern Spain (Sierra de los Filabres and Sierra de Baza) with contrasting climatic conditions. In the more xeric area (Filabres) both pine species showed a sharp growth reduction in response to extreme droughts such as those observed in 1994-1995, 1999 and 2005. The radial growth of both species was enhanced by May and June precipitation of the year of tree-ring formation. P. pinaster showed higher defoliation in the xeric area (Filabres) than in the more mesic area (Baza) but needle loss was not linked to an abrupt growth reduction. Contrastingly, divergent radial growth patterns between trees showing high and low defoliation degrees were found for P. halepensis in the more xeric area, where a negative relationship between recent basal area increment and defoliation was found. Pine plantations in Mediterranean mountains under semi-arid conditions are highly vulnerable to warming-induced droughts. Such marginal stands constitute valuable monitoring systems to assess the negative impacts of drought on tree growth, and to test if management strategies as thinning can mitigate the negative impacts of climate warming on similar drought-stressed forests.

Potassic-aluminotaramite from Sierra de los Filabres, Spain

Potassic-aluminotaramite, ideally A K (CaNa) B (Fe 3 2+ Al 2 ) C (Si 6 Al 2 ) O 22 W (OH) 2 , has been found in a meta-monzonite rock sampled at Sierra de los Filabres, S.E. Spain; the paragenesis that contains the amphibole is mainly formed by feldspar, quartz, and clinopyroxene. This paper reports a complete mineral description and crystal-structure details for this new taramite end-member that has been recognised by IMA-CNMMC with the vote 2007-015. Holotype potassic-aluminotaramite has the experimental unit formula A (Na 0.34 K 0.66 ) ∑1.00 B (Fe 0.01 2+ Na 0.85 Ca 1.14 ) ∑2.00 C (Fe 2.80 2+ Mg 0.33 Al 1.26 Fe 0.46 3+ Ti 0.05 Mn 0.10 ) ∑5.00 T (Si 6.01 Al 1.99 ) ∑8.00 O 22 W (OH 1.96 F 0.03 Cl 0.01 ) ∑2.00 ; a = 9.8505(5), b = 18.0075(9), c = 5.3518(3) A, β = 104.775(4), V = 917.9(2) A 3 ; D calc = 3.40 g/cm 3 . Optics: biaxial (−); α 1.686(1), β 1.703(3), γ 1.706(3) (λ = 589 nm). The ten strongest reflections in the X-ray powder pattern [ d values (in A), I , ( hkl )] are: 8.420, 100, (110); 2.714, 75.03, (151); 2.565, 59.62, (−202); 3.127, 52.54, (310); 2.596, 49.03, (061); 3.400, 37.92, [(131) (041)]; 2.166, 33.71, [(261) (−332)]; 2.340, 32.38, (−351); 2.956, 24.79, (221); 2.297, 24.57, [(−171) (−312)].

Recent large fold nucleation in the upper crust: Insight from gravity, magnetic, magnetotelluric and seismicity data (Sierra de Los Filabres–Sierra de Las Estancias, Internal Zones, Betic Cordillera)

Rheological heterogeneities in the upper-crust have a close relationship with the fold position where rigid bodies could constitute initial perturbations that allow the nucleation of folds. Consequently, establish the position and geometry of anomalous rocks located in the upper-crust by geophysical studies help to understand the folded structure observed on surface. New geological observations in the field, along with gravity, magnetic, magnetotelluric and seismicity data, reveal the subsurface structure in the Sierra de Los Filabres–Sierra de Las Estancias folded region part of the Alpine belt in southern Spain. The geometry of the upper crust is determined by geological field data, 2D gravity models, 2D magnetic models and 2D MT resistivity model, while seismicity evidences the location of the deep active structures. These results allow us to propose that a basic rock body at 4 to 9 km depth has determined the nucleation and development of the Sierra de Los Filabres kilometric antiform. N-vergent large late folds are subjected to a variable present-day stress field. Earthquake focal mechanisms suggest the presence in depth of a regional NW–SE compressive stress field. However, most of the seismogenetic structures do not extend up to the surface, where NW–SE and WNW–ESE outcropping active normal faults are observed, thus indicating a NE–SW extension in the upper crust simultaneous to orthogonal NW–SE compression related to reverse faults and minor folds developed in the Eastern Almanzora Corridor and in the nearby Huércal–Overa Basin. The recent and active tectonic studies of cordilleras hinterland subjected to late folding greatly benefits from the integration of surface observations together with geophysical data.

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.