Análisis de facies de la Capa de Oolitos ferruginosos de Arroyofrío en la Sierra de Arcos (Jurásico, Cordillera Ibérica septentrional)

In this work we have studied the Arroyofrio Bed. This is a classic and largely studied ironstone unit in the Iberian Range. The age of this bed ranges from the Lower Callovian to Middle Oxfordian. This is a complex lithologic unit formed by irregular sedimentary events and several discontinuities associated with stratigraphic gaps of variable extent. In this work five facies containing ferruginous ooids are described and a preliminary study of the carbonate cements and Fe oolite facies is presented. This ironstone bed was formed near to an emergent high (Ejulve high). The oolites formed in a shallow marine subtidal environment. The facies and cement analysis shows that there were no long episodes of subaereal exposure at the Callovian-Oxfordian boundary. These data also demonstrate that these sediments were not deposited in deep marine conditions. The most probable hypothesis is that Fe ooids were formed in shallow subtidal and perhaps intertidal conditions and that they were eventually transported into more distal and relatively deep basinal areas

Callovian and the Callovian - Oxfordian transition sedimentary record in NE Iberian Chain: Taphonomic analysis and palaeogeography

A comparative study is made on Callovian to middle Oxfordian sequences along the Northeastern Iberian Chain (E. Spain). In the NW areas, from Veruela-Ricla to Tosos (SW-S of Zaragoza), Callovian deposits are represented by expanded carbonate sequences (mudstone and marls with a variable content in clastics) ranging from early Bullatus to Athleta Biozone. Farther East in the near area of Moneva-Ariño (Sierra de Arcos) and in the area of Calanda (SE of Zaragoza), this stratigraphic interval is represented by a strongly condensed, 2-4 m thick, highly incomplete sequence. Bullatus to early Anceps biozones are partly represented under bioclastic or oolitic packstone facies. The Callovian-Oxfordian transition interval deposits are represented by a decimeter-thick ironooid fossiliferous limestone condensed sequence (low values of sedimentation rate) formed by expanded sediments (high values of instant rate of sediment accumulation). Ammonite recorded associations frequently show traces of reelaboration and clear evidence of taphonomic condensation. The palaeogeographic evolution of the platform is reconstructed on the basis of extensive sedimentologic studies and on the analysis of taphonomic gradients shown by ammonite associations. Such taphonomic gradients clearly show a shallowing trend of the platform during the Callovian, which would take place earlier in the SE areas (Sierra de Arcos-Calanda) from Gracilis Biozone onwards, and later, from Coronatum Biozone onwards, in the NW areas (Veruela-Ricla to Tosos), the SE area acting as a shallow to temporarily emerged palaeogeographic threshold. The shallowing process would lead to the widespread emersion of the platform from latest Callovian (Lamberti Biozone) to earliest Oxfordian (Mariae and Cordatum biozone, p.p.)Se realiza un estudio comparativo de las sucesiones del Calloviense al Oxfordiense medio en la Cordillera Ibérica nororiental (Rama Aragonesa). En la parte noroccidental, en el sector de Veruela-Ricla a Tosos, del SW al S de Zaragoza, los materiales del Calloviense están representados por sucesiones carbonatadas expandidas (calizas mudstone y margas con un contenido variable en Belsiliciclásticos) que abarcan desde la parte inferior de la Biozona Bullatus hasta la Biozona Athleta. Más al E, en la región de Moneva- Ariño (Sierra de Arcos) y en el sector de Calanda, este intervalo, entre las biozonas Bullatus y Anceps está representado sólo parcialmente, por una sucesión condensada, muy incompleta, en facies de packstone bioclástico o en ocasiones oolítico. Los materiales del intervalo correspondiente a la transición Calloviense-Oxfordiense constituyen una sucesión condensada (= baja tasa de sedimentación) de espesor decimétrico formada por calizas fosilíferas con ooides ferruginosos que constituyen sedimentos expandidos (= altos valores de tasa instantánea de acumulación de sedimento). Las asociaciones registradas de ammonites muestran con frecuencia claras señales de reelaboración tafonómica y evidencias de condensación tafonómica (= asociaciones condensadas). La evolución paleogeográfica de la plataforma se ha reconstruido sobre la base de análisis sedimentológicos extensivos y del análisis de los gradientes tafonómicos mostrados por las asociaciones de ammonites. Estos gradientes muestran claramente la progresiva somerización de la plataforma durante el Calloviense. Esta somerización es más temprana (a partir de la Biozona Gracilis) en el sector de Sierra de Arcos-Calanda, que actuaría como un alto paleogeográfico temporalmente emergido, y más tardía (biozonas Coronatum-Athleta) en el sector noroccidental, entre Veruela-Ricla y Tosos. Dicha somerización culmina al final del Calloviense (Biozona Lamberti) y comienzos del Oxfordiense (biozonas Mariae y Cordatum p.p.) con la probable emersión generalizada de la plataforma

Public Capital and Regional Economic Growth: a SVAR Approach for the Spanish Regions

Recently, a significant share of the empirical analysis on the impact of public capital on regional growth has used multivariate time-series frameworks based on vector autoregressive (VAR) models. Nevertheless, not as much attention has been dedicated to the analysis of the long-run determinants of regional growth processes using multi-region panel data and applying panel integration and co-integration techniques. This paper estimates the dynamic domestic effects of public infrastructure using a structural vector autoregressive (S-VAR) methodology for the Spanish regions. From a methodological point of view, the paper contains several features that can be viewed as a contribution to the existing empirical literature. First, the important issues of the stationarity of the data and the existence and estimation of cointegrating relationships in the long-run are addressed in the context of the analysis of panel data. Secondly, the long-run cointegrating production function is embedded within structural vector error correction (S-VEC) shortrun models to produce consistent estimates of impulse responses, contrary to many researchers who have estimated unrestricted VAR models in levels or VAR models in first differences. The estimates reveal new results with respect to the previous empirical evidence

Lead free piezoelectric ceramics based on Bi0.5(Na0.8K0.2)0.5TiO3 y K0.5Na0.5NbO3 systems

Los materiales cerámicos basados en circonato-titanato de plomo, Pb(Zr,Ti)O3(PZT), son muy conocidos por sus excelentes propiedades piezoeléctricas. Si bien, estos materiales se producen generalmente a partir de la técnica de mezcla de óxidos, la cual es relativamente simple y económica, en su formulación se emplea un alto contenido de óxido de plomo (aprox. 70%). Dado que el plomo y sus compuestos son considerados tóxicos y peligrosos, no sólo por la polución directa que genera el proceso de manufactura y maquinado de los compuestos, sino también porque los productos que contienen PZT no pueden ser reciclados, recientemente se han comenzado a investigar diferentes composiciones piezoeléctricas para su reemplazo. En este trabajo, se analizan algunos desarrollos propios en el campo de los materiales piezoeléctricos libres de plomo donde se enfatiza la correlación existente entre las propiedades finales, la microestructura desarrollada y la estructura estabilizada.Ceramics based on lead zirconium titanate Pb(Zr,Ti)O3 (PZT) are well known for their excellent piezoelectric properties. These materials are generally produced by solid reaction technique, which is relatively simple and economical; however their production needs high lead oxide content (approx. 70%). Lead and its compounds are considered toxic and dangerous, due to direct pollution generated by the manufacturing process and machining of the compounds, and the inability to recycle products containing PZT. Therefore, other piezoelectric compositions based on lead free materials have begun investigated. In this paper, some developments in the field of lead-free piezoelectric materials, correlating the structure and microstructure with the properties materials properties are analyzed.Fil: Castro, Miriam Susana. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Camargo, Javier Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Taub, Jonathan. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Fernandez, J. F.. Instituto de Ceramica y Vidrio de Madrid; EspañaFil: Rubio-Marcos, F.. Instituto de Ceramica y Vidrio de Madrid; EspañaFil: Ramajo, Leandro Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Climate change-related risks and adaptation potential in Central and South America during the 21st century

Climate-related risks in Central and South America have received increased attention and concern in science and policy, but an up-to-date comprehensive review and synthesis of risks and adaptation potential is currently missing. For this paper we evaluated over 200 peer-reviewed articles and grey literature documents published since 2012. We found that climate change in Central and South America during the 21st century may increase the risk to severe levels for the following topical risk clusters: (a) Food insecurity; (b) Floods and landslides; (c) Water scarcity; (d) Epidemics of vector-borne diseases; (e) Amazon Forest biome shift; (f). Coral bleaching; (g) Coastal risks of sea level rise, storm surges and erosion; (h) Systemic failure due to cascading impacts of hazards and epidemics. Our synthesis also identified feasible adaptation measures for each risk. The impacts of the risks will be heterogeneous throughout the region, with rural communities, Indigenous peoples, Afro-Latin Americans, women, disabled people, and migrants identified as being the most severely affected. We refer to a number of adaptation options for each risk. However, unabated climate change together with low adaptive capacity will strictly limit adaptation options. Immediate strengthening of policies for building adaptive capacity and increase of research on the risk-adaptation nexus in Central and South America are paramount. Our findings might contribute to guide the adjustment and emphasis of adaptation policies and climate risk management strategies from local to national level

Photosynthetic activity buffers ocean acidification in seagrass meadows

Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass (<i>Posidonia oceanica</i>) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (&Omega;_Ar)) and O₂ within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pH_NBS and max and range &Omega;_Ar. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min &Omega;_Ar, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range &Omega;_Ar within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, &Omega;_Ar and carbonate deposition. <br></br> Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows

El magmatismo alcalino del Triásico Superior en el NO de la Cadena Ibérica (España)

We have carried out a complete study of the Upper-Triassic alkaline magmatism on the northwestern margin of the Iberian Chain. This magmatism is composed of mafic sills, which intrude the Keuper facies in two geographic sectors: the Cameros Massif (NW) and the Moncayo Massif (SE). In both of these sectors, the rocks are characterised by an intense alteration (spilitisation). The field relationships point to an Upper Triassic age for the studied sills, given that: 1) interactions are recognised between the magma and wet, unconsolidated host sediments, suggesting that the magma was emplaced during or shortly after the deposition of the Keuper facies; 2) in the Moncayo sector a conglomerate bed that includes igneous clasts overlaies the sills and passes upwards to the Norian-Rhaetian Imón Fm. According to the petrological and geochemical features of the sills, an internal differentiation can be recognised inwards, with the developments of three zones: chilled margins, central facies and pegmatoid facies. The rocks are porphyritic and are mainly composed of phenocrysts of pseudomorphed olivine and microcrysts of plagioclase, opaque minerals and minor clinopyroxene. Vesicles and xenoliths of the host sedimentary rocks are also recognised, especially at the chilled margins. The mineral assemblage is constant across the sills but the mineral proportions vary among the different zones. The sills are basic to intermediate rocks. They are classified as basalts to dacites with an alkaline geochemical affinity. According to the trace element contents, this magmatism is related to an enriched sub-lithospheric mantle source affected by crustal contamination. Considering the Upper Triassic magmatisms from southwestern Europe, two types can be distinguished. On the one hand, the magmatisms in the Catalonian Coastal Ranges and SE France are paleogeographically located in the inner platform and are related to deep, astenospheric mantle sources with no evidence of crustal contamination. On the other hand, the magmatisms in the NW Iberian Chain –this study-, the External Betics and the Brescian Prealps are situated in a more litoral position and are related to a shallower, lithospheric mantle with evidence of crustal contamination. These differences could be related to the thickness of the continental crust, which might be thinner in the inner areas of the platform.Se ha realizado un estudio completo del magmatismo alcalino del Triásico Superior del margen noroccidental de la Cadena Ibérica. Este magmatismo consta de sills máficos emplazados entre los materiales sedimentarios de la Facies Keuper en dos sectores: Macizo de Cameros (NO) y Macizo del Moncayo (SE). En ambos sectores, las rocas estudiadas se caracterizan por una intensa alteración (espilitización). Las relaciones de campo apuntan a una edad de los sills estudiados de Triásico Superior dado que: 1) se reconocen interacciones entre el magma y el sedimento encajante sin consolidar, que sugieren su emplazamiento coetáneo con el depósito de la facies Keuper o poco posterior y, 2) se observa, en el sector de Moncayo, un nivel conglomerático con cantos de rocas ígneas similares a las que forman los sills, depositado entre los sedimentos argilíticos que se disponen por encima de los sills y siempre, bajo la Fm. Imón de edad Noriense terminal a Retiense inferior. Las características petrológicas y geoquímicas de los sills sugieren una diferenciación hacia el interior de los mismos, reconociéndose tres zonas: borde enfriado, facies central y facies pegmatoide. Las rocas son porfídicas y tienen una asociación mineral común formada por fenocristales de olivino alterado y una mesostasia compuesta por microcristales de plagioclasa, opacos y clinopiroxeno. También se reconocen vesículas y enclaves de la roca sedimentaria encajante, especialmente en el borde enfriado. Las proporciones modales varían entre las tres facies reconocidas. Los sills están formados por rocas básicas a intermedias, clasificadas desde basaltos a dacitas, con afinidad alcalina. De acuerdo a sus contenidos en elementos traza, este magmatismo está relacionado con una fuente mantélica sublitosférica enriquecida, afectada por contaminación cortical. Considerando los magmatismos del Triásico Superior del suroeste de Europa, pueden establecerse dos tipos. Por un lado, los magmatismos aflorantes en las Cadenas Costero Catalanas y el Sur de Francia estaban paleogeográficamente situadas hacia zonas internas de la plataforma y se relacionan con un manto profundo, astenosférico, sin evidencias de contaminación cortical. Por el contrario, los magmatismos de las áreas más occidentales y septentrionales (NO de la Cadena Ibérica –este estudio-, Zonas Externas de las Béticas y Prealpes de Brescia), próximas al litoral paleogeográfico, se relacionan con un manto más superficial, litosférico y muestran evidencias de contaminación cortical. Todas estas diferencias observadas pueden relacionarse con variaciones del espesor de la corteza continental, más adelgazada hacia las zonas internas de la plataforma

Influence of the sintering temperature on ferroelectric properties of potassium-sodium niobate piezoelectric ceramics

The effect of sintering condition on structure, microstructure, and ferroelectric properties of (K0.44Na0.52Li0.04) (Nb0.86Ta0.10Sb0.04)- O3 (KNL-NTS) has been investigated. Ceramic powders have been synthesized by the solid-state reaction method and sintered at different temperatures (1115°C, 1125°C, and 1140°C). Then, samples were characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and impedance spectroscopy. Through XRD results, the perovskite structure and small peaks corresponding to a secondary phase were detected. Ceramics processed at the highest temperatures showed higher densities and good piezoelectric properties (d33, Kp, and Kt), particularly specimens sintered at 1125°C presented the highest piezoelectric performance.Fil: Cortés, J. A.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Camargo, Javier Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rachia, M. F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Rubio Marcos, Fernando. Instituto de Cerámica y Vidrio de Madrid; España. Universidad Nebrija; EspañaFil: Ramajo, Leandro Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Castro, Miriam Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ramírez, M. A.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Evaluación multidisciplinar 3D de una estructura kárstica asociada a colapso y subsidencia (Cuenca del Ebro)

La propagación de cavidades de disolución localizadas por debajo de series aluviales genera una serie de evidencias cuya representación superficial, en ocasiones, puede no ser indicativa de su extensión real en profundidad. La propagación de cavidades a través de medios heterogéneos, en los que pueden existir niveles cementados, puede producir cambios en la progresión de dichas cavidades y la identificación en superficie de grietas, colapsos, o zonas de subsidencia que pueden involucrar decenas de miles de metros cúbicos de material inestable. Cualquier tipo de evaluación de soluciones mitigadoras en estos contextos debe considerar la amplitud de estos volúmenes y el origen del proceso con independencia de la actividad registrada en superficie. En este trabajo se aborda un estudio integrado con el objetivo de determinar la estructura de un sector con evidencias de actividad kárstica superficial y evaluar su extensión y desarrollo tridimensional integrando el análisis geomorfológico, de inspección de campo, geofísica (GPR) y sondeos. The propagation of solution cavities located below alluvial deposits produce surficial evidences that, in some cases, cannot be representative of their actual extension at depth. Cavity propagation through heterogeneous media, for example with interbedded cemented levels, can produce changes in the propagation of deformation producing the identification of cracks, collapses or subsidence zones at the surface. These processes can involve thousands of cubic meters of unstable materials. Any evaluation of mitigation tasks, in this context, needs to consider: i) the amplitude of the affected volumes and ii) the in depth origin with independence of the surficial recorded activity In this work an integrated analysis is developed to evaluate the size and 3D structure of a sector with surficial evidences of karstic activity integrating geomorphological analysis, field inspection, geophysics (GPR) and boreholes