Fossil associations from the middle and upper Eocene strata of the Pamplona Basin and surrounding areas (Navarre, western Pyrenees)

Fossil associations from the middle and upper Eocene (Bartonian and Priabonian) sedimentary succession of the Pamplona Basin are described. This succession was accumulated in the western part of the South Pyrenean peripheral foreland basin and extends from deep-marine turbiditic (Ezkaba Sandstone Formation) to deltaic (Pamplona Marl, Ardanatz Sandstone and Ilundain Marl formations) and marginal marine deposits (Gendulain Formation). The micropalaeontological content is high. It is dominated by foraminifera, and common ostracods and other microfossils are also present. The fossil ichnoasssemblages include at least 23 ichnogenera and 28 ichnospecies indicative of Nereites, Cruziana, Glossifungites and ?Scoyenia-Mermia ichnofacies. Body macrofossils of 78 taxa corresponding to macroforaminifera, sponges, corals, bryozoans, brachiopods, annelids, molluscs, arthropods, echinoderms and vertebrates have been identified. Both the number of ichnotaxa and of species (e. g. bryozoans, molluscs and condrichthyans) may be considerably higher. Body fossil assemblages are comparable to those from the Eocene of the Nord Pyrenean area (Basque Coast), and also to those from the Eocene of the west-central and eastern part of South Pyrenean area (Aragon and Catalonia). At the European scale, the molluscs assemblages seem endemic from the Pyrenean area, although several Tethyan (Italy and Alps) and Northern elements (Paris basin and Normandy) have been recorded. Palaeontological data of studied sedimentary units fit well with the shallowing process that throughout the middle and late Eocene occurs in the area, according to the sedimentological and stratigraphical data.

On the microstructure, growth pattern and original porosity of belemnite rostra: insights from calcitic Jurassic belemnites

Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.

Indicators on community art practices: some reflections

From the Divercity project, the article reflects on methodology, good practices and indicators useful for community art practices. At first term, social exclusión is defined as well as community art, and which features it presents. Subsequently, the article reviews the indicators that are being used to measure the success or achievement of community arts practice, raising criticism from equality and including indicators that measure the well-being of women.

Programas de tertulia política en Twitter: un modelo neurocomunicativo de análisis del discurso

En este trabajo aplicamos a la red social Twitter un modelo de análisis del discurso político y mediático desarrollado en publicaciones previas, que permite hacer compatible el estudio de los datos discursivos con propuestas explicativas surgidas a propósito de la comunicación política (neurocomunicación) y de la comunicación digital (la red como quinto estado, convergencia, inteligencia colectiva). Asumimos que hay categorías del encuadre discursivo (frame) que pueden ser tratadas como indicadores de habilidades cognitivas y comunicativas. Analizamos estas categorías agrupándolas en tres dimensiones fundamentales: la intencional (ilocutividad del tuit, encuadre interpretativo de las etiquetas), referencial (temas, protagonistas), e interactiva (alineamiento estructural, predictibilidad; marcas de intertextualidad y dialogismo; afiliación partidista). El corpus consta de 4116 tuits: 3000 tuits pertenecientes a los programas Al Rojo Vivo (La Sexta: A3 Media), Las Mañanas Cuatro (Cuatro: Mediaset) y Los Desayunos de TVE (RTVE), 1116 tuits de seguidores de los programas, que corresponden a 45 tuits de cada programa. Los resultados confirman que el modelo permite establecer diferentes perfiles de subjetividad política en las cuentas de Twitter.