Los Volcanes en la red (www): la enciclopedia del siglo XXI

No toda la información encontrada en Internet resulta ser fiable y válida, de modo que es necesaria una evaluación crítica sobre los distintos materiales antes de escoger los más apropiados. En este artículo se presentan y analizan distintos recursos educativos de internet relacionados con el fenómeno del volcanismo y peligros asociados. Todos ellos pueden ser de gran utilidad para docentes, divulgadores científicos y alumnos tanto para mejorar su formación en estos temas, como para complementar su propio material docente o de divulgación

Subduction-related fluids influence on the Oligo-Miocene transitional magmatism of the Sulcis area (SW Sardinia, Italy)

The Sardinia-Corsica microplate was involved in OligoMiocene times in a SE-ward drift and counterclockwise rotation from the European margin in western Mediterranean to its current position. This movement was caused by the roll-back play of a NWward subducting oceanic plate under this margin and produced the detachment of this microplate from the continental margin and the openning of the Liguro-Provençal basin. As a result of the subduction abundant calc-alkaline magmatism of orogenic affinity occurred, mostly in the western sectors of Sardinia. In the final stages of the Miocene subduction and magmatism, coinciding with an increase in extensional tectonics, in the Sulcis area magmatism shifted from typical orogenic andesites to more evolved products of transitional character, ranging from trachydacites to rhyolites, with the relevant presence of peralkaline magmas (comendites), which were emplaced mostly as widespread ignimbrites reaching up to 20 km3 in volume and forming a pile over 200 m thick

Cannibalization of previous Na-rich clinopyroxenes by ascending basic magmas of the Garrotxa Volcanic Field (NE Spain)

The Garrotxa Volcanic Field (GVF) is a Quaternary monogenetic volcanic field belonging to the NE Spain volcanic province, recording a Neogene alkaline intraplate magmatic activity consequence of the rift-type extensional tectonics that has affected the eastern margin of Iberia since late Oligocene

Volcanic ash leaching as a means of tracing the environmental impact of the 2011 Grímsvötn eruption, Iceland

The Grímsvötn volcanic eruption, from 21 to 28 May, 2011, was the largest eruption of the Grímsvötn Volcanic System since 1873, with a Volcanic Explosivity Index (VEI) of magnitude 4. The main geochemical features of the potential environmental impact of the volcanic ash-water interaction were determined using two different leaching methods as proxies (batch and vertical flow-through column experiments). Ash consists of glass with minor amounts of plagioclase, clinopyroxene, diopside, olivine and iron sulphide; this latter mineral phase is very rare in juvenile ash. Ash grain morphology and size reflect the intense interaction of magma and water during eruption. Batch and column leaching tests in deionised water indicate that Na, K, Ca, Mg, Si, Cl, S and F had the highest potential geochemical fluxes to the environment. Release of various elements from volcanic ash took place immediately through dissolution of soluble salts from the ash surface. Element solubilities of Grímsvötn ash regarding bulk ash composition were <1 %. Combining the element solubilities and the total estimated mass of tephra (7.29 × 1014 g), the total inputs of environmentally important elements were estimated to be 8.91 × 109 g Ca, 7.02 × 109 g S, 1.10 × 109 g Cl, 9.91 × 108 g Mg, 9.91 × 108 g Fe and 1.45 × 108 g P The potential environmental problems were mainly associated with the release of F (5.19 × 109 g)

Mantle source heterogeneity beneath the Garrotxa Volcanic Field (NE Spain)

The Neogene volcanism in NE Spain, which is related to the rift-type extensional tectonics affecting the eastern margin of Iberia since late Oligocene, is well represented in the basalts and basanites from the Garrotxa Volcanic Field (GVF)

Improving transversal competences by using wikis in collaborative work

Work on transversal competences in university degrees is a teaching line entirely established since the implementation of the European Credit Transfer System (ECTS). Nevertheless, undergraduate students present shortcomings in the development of some of these competences, especially on collaborative work, time management, oral and writing expression, and on the use of information resources. This paper presents a virtual tool and associated guidelines to enhance the information management during the development of collaborative works, and to facilitate the information availability among the students. Moreover, this tool and the guideline improve the individual monitoring and evaluation of the contributions of the students to the work. The proposal presented in this work belongs to a teaching innovation project carried out in the Earth Sciences Faculty of the Universitat de Barcelona, and implemented in the subjects General Geology (first-year in the Engineering Geology degree, 6 ECTS) and Geochemistry (third-year course in the Geology degree, 9 ECTS)Peer Reviewe

Creació d'una Eina de suport per a la docència en Geoquímica. Una eina d'aprenentatge autònom i d'avaluació

La proposta presentada s'emmarca en un projecte d'innovació docent de la Universitat de Barcelona. L'objectiu és desenvolupar una nova eina interactiva que d'una banda ajudi els alumnes a reforçar i/o ampliar els coneixements de geoquímica de manera autònoma i, de l'altra, sigui un nou recurs d'avaluació per al professorat. Amb el desenvolupament d'aquest eina, l'alumnat disposarà d'un recurs didàctic que li permetrà madurar i ampliar el seus coneixements en el camp de la geoquímica

Green color chemical recipes in stained glass windows of NE Spain and N Italy (XIIIth to XVth centuries)

A great number of medieval religious buildings in Europe contain stained glass windows. A number of original glass fragments (i.e. with original medieval lead framework) coming from restoration projects (Girona, Tarragona, Pedralbes Monastery at Barcelona (Spain); the Siena Cathedral, the San Petronio Basilica and the San Giacomo Maggiore church in Bologna (Italy)) have been analyzed in term of major, minor and trace elements

Pyroclastic volcanic ash as a potential precursor of alkali-activated binders - A case study from Tajogaite (La Palma, Canary Islands) volcano eruption

The volcanic eruption of Tajogaite in La Palma (Canary Islands, Spain) produced approximately 200 Mm3 of fine lapilli and ash. Using this volcanic ash (VA) to produce alkali-activated binders (AABs) fosters a sustainable approach to binder manufacturing, aligning with the principles of a circular economy and reducing reliance on non-renewable resources. The feasibility of using VA as a sole precursor for the formulation of sustainable AABs was evaluated based on its composition and physical-chemical properties. To this end, a comprehensive physicochemical characterization of VA was carried out and the physical, mechanical, and environmental properties of the binders formulated were analyzed. The physical-chemical analysis reveals the neoformation of typical secondary reaction products, such as NASH and (C,N)ASH gels. The microstructure analysis reveals that the AABs formulated using 6 M and 8 M NaOH activator solutions contain homogeneously dispersed unreacted VA particles within the binder matrix, providing increased cohesion and mechanical strength. The highest compressive resistance of AABs formulated using only VA as the precursor was achieved with a 6 M NaOH activator solution and a curing temperature of 60 ◦C, reaching a strength of 16 MPa. Although alkaline activation enhances the release of some metals and metalloids contained in the VA, the study of the environmental requirements at the end of the life cycle of the formulated AABs allows them to be classified as nonhazardous materials

Coexistence of calc-alkaline and ultrapotassic alkaline magmas at Mounts Cimini : evidence for transition from the Tuscan to the Roman Magmatic Provinces (central Italy)

The volcanic complex of Mts. Cimini (~0.90-1.30Ma) represents the geographical and chronological transition between the Tuscan Magmatic Province (TMP) and the Roman Magmatic Province (RMP), in central Italy. Major and trace elements, and Sr, Nd and Pb isotopes of whole-rock, as well as mineral chemistry analyses, were carried out on samples representative of the different petrographic and chronological units of Mts. Cimini. In particular, we focused on the olivine-bearing latites of Mts. Cimini that are the most mafic magmas, belong to the last phase of this volcanic activity, and are heterogeneous in highly incompatible element ratios and Sr-isotope compositions. We suggest that such heterogeneity reflects the occurrence of a heterogeneous upper mantle beneath central Italy, in which different portions, e.g., the sources of both the TMP and RMP, are characterized by distinct geochemical and petrographic features. In this scenario, about 900ka ago, the olivine-bearing latites mark the progressive decline of the TMP magma production in favour of partial melting of the RMP mantle region, thus recording the coexistence of both ultrapotassic alkaline and calc-alkaline magmas in the same volcanic region