50 research outputs found

    Estudio palinológico de los sedimentos maastrichtienses del Barranco de la Posa (Prepirineo, Lérida, España)

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    El Maastrichtiense que se extiende entre Tremp y Coll de Nargó está representado por depósitos de carácter lagunar y salobre, con pequeños niveles marinos intercqlados . En la sección estudiada l a intercalación marina corresponde a un banco de Hippurites castroi al que acompañan a l g unos coral es . Los Narmapolles no son muy numerosos ni en especies ni en individuos . Entre los tipos 'que caracterizan la vegetación cabe destacar las formas de Inaperturados, ( Taxodiaceae-Cupressaceae) , Palmae y t ipo Platycarya . Localmente Cycadale~, Cupuliferoipollenites y Subtriporopollenites pueden ser abundantes. La frecuencia de Cycadales + Palmae en el conjunto esporopolínico de La Posa se aproxima al tipo de asociación polínica del Maastrichtiense de Africa pro parte. Sin embargo, Trilobospori tes ( Tuberos isporites) se encuentra en la l ocalidad tipo del Maastrichtiense, en la región boreal. Por el momento , parece que se trata de un conjunto pol ínico del r~aastrichtiense con un carácter parti cular en relación a los i ndicadosLe Maastrichtien affleurant entre Tremp et Coll de Nargó est représenté par dép8ts lagunaires et saum§tres ave e ni veaux marins i ntercalés. A la section étudiée 1 ' intercalation mar ine est determinée par un banc a Hippurites castroi avec quelques coraux . Le nombre des taxa et la quantitée des Normapolles ne sont pas tres élevées . En ce qui concerne les types qui caractérisent la végetation, les polles i na perturés ( TaxodiaceaeCupressaceae) 1 Palmae et l e type de Pl atycarya sont en premier l i eu remarquables. Localement les Cycadales , Cupuliferoipolleni tes et Subtriporopol l enites peuvent se rencontrer en quantitée remarquable . L' a bondance des formes Cycadal es + Palmae se révéle au type d'association pollin i que du ~1aastric h tien en 1' Afrique pro parte . Mai s Trilobospori tes ( Tuberosisporites) se trouve dans la l ocal i tés type de Maastricht 1 dans la région boréale. A notre avis il s'agit d 'un type d'association pollinique du Maastrichtien particulier 1 par rapport aux précédent

    Primeros datos cromoestratigráficos de las series evaporíticas del triásico superior de Valencia (España)

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    El Triásico Superior del sector central valenciano de la Cordillera Ibérica presenta una facies germánica (Keuper) integrada por dos secuencias evaporíticas separadas por un episodio detrítico principal. Los datos  preliminares obtenidos de una investigación palinológica en curso revelan una edad Karniense para todos estos materiales

    Cronoestratigrafía (Palinología) del Triásico Sudpirenaico y del Pirineo Vasco-Cantábrico

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    This paper presients a general chronostratigraphy of the south Pyrenean Triassic basi:d on palynological studies. The Triassic in Les Nogueres-Cadí and the Basque Country areas is divided into the Buntsandstein, Muschelkalk and Keuper facies and the Isábena Forrnation. The Conglomeratic, sandstone and lutitic Unit of the Buntsandstein in the Puerto dr Otxondo (Basque Country) presents Stellapollenites thiergartii and together with the absence of Praecirculina granifer, suggests a Lower-middle Anisian age. The Lutitic Unit of the Buntsandstein in Igüem, Sant Sebastia de Buseu and Baga (Les Nogueres-Cadí) presenits Illinites kosankeii and Stellapollenites thiergartii, and the absence of Praecirculina granifer, indicates a Lower Anisian age. The Muschelkailk in Hostalets (Les Nogueres) presents Camerosporites secatus, suggesting an upper Ladinian age. The transit zone between the Muschelkaik and the Keuper facies in Odkn (Cadí) shows a palynological assemblage with Patinasporites densus, Partitisporites quadruplicis and Staurosaccites quadrifidus, indicating a Camain age, possibly Middie-upper Camian. The lower part of the Keuper in Noguera de Tor and Adons, in the Les Nogueres area, presents a palynological assemblage with Classopollis, Granuloperculatipollis rudis, Ovalipollis ovalis, Praecirculina granifer and Triadispora. The abundance of Classopollis and the presence of Granul~p~erculatipollrius dis suggest a Norian age, possibly lower-middle. The upper part of the Keuper in La Nou (Pedraforca) is Rhaetian in age due to the presence of cf. Deltaidospora and cf. Taeniasporites. The base of tlie Isábena Formation in Noves de Segre presents Corollina zwolinskae and Cerebropollenites pseudomassulae, indicating a Rhaetian age. The palynological studies, together with the forarninifera and conodonta data, deteimine the existence of important stratigraphicc hiatuses in the south Pyrenean Triassic supercycle

    Stratigraphy and petrology of the Miocene Montjuïc delta (Barcelona, Spain)

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    The Neogene rift in the Catalan Coastal Ranges, which is located in the NE part of the Eastern Iberian Margin, corresponds to a system of grabens formed at the north-western edge of the Valencia Trough. In the central part of the Catalan Coastal Ranges are the Vallès - Penedès half-graben in the onshore and the Barcelona half-graben in the offshore, which are separated by the Garraf and the Collserola-Montnegre horsts. Montjuïc hill is a tilted block, which is located to the S of the Barcelona city, between the Collserola-Montnegre horst and the Barcelona half-graben . The Middle Miocene section of Montjuïc is constituted by an alternation of conglomerate, sandstone, mudstone and marlstone beds. The Montjuïc section was divided into four lithostratigraphic units from base to top: (1) The Morrot conglomerate and sandstone Unit, interpreted as delta plain deposits; (2) the Castell conglomerate, sandstone and mudstone Unit considered as proximal delta front deposits; (3) the Miramar marlstone Unit attributed to prodelta deposits; and (4) the Mirador conglomerate, sandstone and mudstone Unit interpreted as delta front deposits. As regards the foraminifera association, the Miocene of Montjuïc may be attributed to the N9-N10 zones of Blow, indicating a Serravallian age. The palaeobotanical record suggests that the climate during the deposition of the Miocene of Montjuïc was temperate-warm and humid. The sandstones and conglomerates are litharenites and lithorudites; they show variable amounts of matrix and are well cemented. The main framework components are quartz, rock fragments and K-feldspar. The Collserola mountain, where Palaeozoic materials crop out is the deduced source area. Montjuïc sandstones are characterized by an early silicic cementation consisting of K-feldspar overgrowths, quartz overgrowths, mesoquartz intergranular cement and a microquartz transformation of a former detrital matrix. A surface cementation is considered for these cements in the absence of compaction and the geological setting

    Stratigraphy and petrology of the Miocene Montjuic delta: (Barcelona, Spain).

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    The Neogene rift in the Catalan Coastal Ranges, which is located in the NE part of the Eastern Iberian Margin, corresponds to a system of grabens formed at the nort h - we s t e rn edge of the Valencia Trough. In the central part of the Catalan Coastal Ranges are the Valls - Peneds half-graben in the onshore and the Barcelona half-graben in the offshore, which are separated by the Garraf and the Collserola-Montnegre horsts. Montjuc hill is a tilted block, which is located to the S of the Barcelona city, between the Collserola-Montn egre horst and the Barcelona half-graben . The Middle Miocene section of Montjuc is constituted by an alternation of conglomerate, sandstone, mudstone and marlstone beds. The Montjuc section was divided into four lithostratigraphic units from base to top: (1) The Morrot conglomerate and sandstone Unit, interpreted as delta plain deposits; (2) the Castell conglomerate, sandstone and mudstone Unit considered as proximal delta front deposits; (3) the Miramar marlstone Unit attribute

    La serie Triasica de Los Pastores (Algeciras)

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    Seven superimposed lithostratigraphic units have been distinguished in the Upper Trias of Los Pastores (Algeciras). The four lower units (1 to 4) show clayey-sandy-evaporitic Keuper facies. Pollen associations obtained from dark pelitic levels, and bivalves sampled from carbonate intercalations within these four lower units allow to date them as Carnian. These lower units can be correlated with the K1 to K3 units of the Keuper of the Subbetic and of other regions of the Iberian Peninsula. Concerning the three higher units, the unit 6 is pelitic-carbonatic and evaporitic and it also bears Carnian pollen associations. The units 5 and 7, however, are carbonatic and show clearly marine facies and organisms (Involutinidae and dasycladacean algae) of the same type than those shown by the Upper Triassic of Alpine Facies of the Internal Zones of the Chain (Alpujarrides and Rondaides). The Trias of Los Pastores belongs to an arid ecuatorial phytogeographical province, whose the vegetation was dominated by xerophytic elements. It was deposited in a wide coastal flat with marginal terrigenuos influence and close to a carbonate platform, in peritidal and shallow marine depositional environments, very sensitive to sea-level fluctuations. The marine carbonate intercalations bear low-diversity, dwarf and opportunistic marine faunal associations, typical of shallow, restricted, unstable and ecologicaUy inmature environments, as it has been confirmed independently by facies analysis.En el Trías de superior de Los Pastores (Algeciras) se han podido diferenciar siete unidades litoestratigráficas superpuestas. Las unidades inferiores (1 a 4) muestran facies arcilloso- arenoso-evaporíticas de tipo Keuper. De ellas se han obtenido asociaciones del Carniense, de polen, procedentes de niveles pelíticos oscuros, y de bivalvos, procedentes de intercalaciones carbonatadas. Estas unidades inferiores se pueden correlacionar con las unidades K1 a K3 del Keuper del Subbético y del resto de la Península Ibérica. De las tres unidades superiores, la unidad 6 es de naturaleza pelítico-carbonatada y evaporítica y ha suministrado asimismo asociaciones de polen del Carniense. Las unidades 5 y 7, sin embargo, son de naturaleza carbonatada y presentan facies y organ.ismos francamente marinos (Involutínidos y algas dasycladáceas) de características análogas a las que muestra el Trías superior de Facies Alpina de las Zonas Internas de la Cordillera Bética (Rondaides y Alpujárrides). El Trías de Los Pastores pertenece a una provincia fitogeográfica ecuatorial árida, cuya vegetación estaba dominada por elementos xerofíticos. Se depositó en una extensa llanura costera con influencia terrígena marginal y adyacente a una plataforma carbonatada, en ambientes de tipo perimareal y marino muy somero, muy sensibles a las variaciones en el nivel del mar. Las intercalaciones carbonatadas marinas contienen asociaciones de faunas autóctonas de baja diversidad, oportunistas y de nanismo endémico, propias de ambientes someros, restringidos, inestables e inmaduros ecológicamente, que confirman las características del medio sedimentario deducidas del análisis de las facies

    Deep incision in an Aptian carbonate succession indicates major sea-level fall in the Cretaceous

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    Long-term relative sea-level cycles (0 5 to 6 Myr) have yet to be fully understood for the Cretaceous. During the Aptian, in the northern Maestrat Basin (Eastern Iberian Peninsula), fault-controlled subsidence created depositional space, but eustasy governed changes in depositional trends. Relative sea-level history was reconstructed by sequence stratigraphic analysis. Two forced regressive stages of relative sea-level were recognized within three depositional sequences. The first stage is late Early Aptian age (intra Dufrenoyia furcata Zone) and is characterized by foreshore to upper shoreface sedimentary wedges, which occur detached from a highstand carbonate platform, and were deposited above basin marls. The amplitude of relative sea-level drop was in the order of tens of metres, with a duration of 2 km wide and cut 115 m down into the underlying Aptian succession. With the subsequent transgression, the incision was back-filled with peritidal to shallow subtidal deposits. The changes in depositional trends, lithofacies evolution and geometric relation of the stratigraphic units characterized are similar to those observed in coeval rocks within the Maestrat Basin, as well as in other correlative basins elsewhere. The pace and magnitude of the two relative sea-level drops identified fall within the glacio-eustatic domain. In the Maestrat Basin, terrestrial palynological studies provide evidence that the late Early and Late Aptian climate was cooler than the earliest part of the Early Aptian and the Albian Stage, which were characterized by warmer environmental conditions. The outcrops documented here are significant because they preserve the results of Aptian long-term sea-level trends that are often only recognizable on larger scales (i.e. seismic) such as for the Arabian Plate

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]

    Analyzing and Modeling Real-World Phenomena with Complex Networks: A Survey of Applications

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    The success of new scientific areas can be assessed by their potential for contributing to new theoretical approaches and in applications to real-world problems. Complex networks have fared extremely well in both of these aspects, with their sound theoretical basis developed over the years and with a variety of applications. In this survey, we analyze the applications of complex networks to real-world problems and data, with emphasis in representation, analysis and modeling, after an introduction to the main concepts and models. A diversity of phenomena are surveyed, which may be classified into no less than 22 areas, providing a clear indication of the impact of the field of complex networks.Comment: 103 pages, 3 figures and 7 tables. A working manuscript, suggestions are welcome

    Precisiones cronoestratigráficas sobre la Fm. Escucha en el sector noroeste de la cuenca del Maestrazgo. Cordillera Ibérica oriental

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    Uno de los problemas clásicos en el estudio del registro sedimentario cretácico de la Cordillera Ibérica es la datación cronoestratigráfica de los materiales detriticos que subyacen al cretácico superior calcáreo, debido a su carácter continental y de transición. En el presente trabajo se muestrean dos series de la Fm. Escucha situadas en los depocentros de las cubetas de Calanda y de Castellote, para realizar un análisis palinológico de las mismas y compararlo con otros análisis realizados en la cubeta de Traiguera, en donde la edad está contrastada con el contenido en ammonites. Los resultados de este análisis, muestran un contenido en microflora equivalente para las dos series, asi como con las de Benassal, Benifassa, Traiguera y Salom. Este hecho nos lleva a datar a la Fm. Escucha en este sector como Albiense inferior terminal- Albiense medio, con 10 cual se contribuye a aclarar las relaciones estratigráficas entre las formaciones de Escucha, Val de la Piedra y Calizas de Benassal
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