1,721,372 research outputs found
Active geodynamic in the central Mediterranean: Transfer of mantle fluids across the eastern Sicily
No full textTransfer of mantle derived fluids across the Calabrian-Peloritan arc: tectonic and geodynamic implications
No full textMantle degassing occurs principally through active volcanic systems and young oceanic lithosphere. Tectonically active regions on the continental crust may additionally contribute a (poorly quantified) fraction of the deep CO2 budget.
We studied volatiles in thermal manifestations along the seismically active Nebrodi-Peloritani chains (NE Sicily), to investigate the origin of thermalism and the sources of the outgassing fluids. The geological evolution of the area has been controlled by the interaction between the European and African plates and links the African Maghreb with the European Apennines.
The collected samples exhibit 3He excess, supporting active outgassing of mantle-derived volatiles. The computed mantle-derived He fluxes are up to 3 orders of magnitude higher than those in stable continental areas. These high fluxes support and advective transport of fluids through the regional tectonic discontinuities.
The investigated area, despite being a chain, is located between two of most active worldwide volcanic systems: Mt. Etna to south and the subduction-related Aeolian arc to north. Geophysical studies and experimental models [Piromallo et al., 2003] suggest the existence of toroidal flows in the mantle that, bypassing the subduction plate, produce mantle upraise in the area [Faccenna et al., 2011], eventually leading to magma accumulation at the mantle-crust interface, or in the crust. We propose deep fluids ascent occurs via deep regional tectonic discontinuities (the Eolie-Tindari-Letojanni fault system, figure 1), interpreted by either an offshoot of a regional lithospheric structure in the Ionian Sea [Polonia et al., 2016], or a slab tear or STEP type structure at the margin of subduction ionian plate [Doglioni et al., 2001]. Our study supports a) the possible presence of magmatic intrusions below this sector of the Maghrebian-Apenninic chain; b) the active role of the regional discontinuities in transferring mantle fluids towards the surface and c) the possible age of the magmatic intrusions.
Finally our results furnish new contributions to the crust-mantle tectonic in a region that is dominated by the interaction of two plates. Hence this study produces new contributions for a better knowledge of the geodynamic evolution of Mediterranea
Fluid geochemistry and CO2 output in the southern Apennine (Italy): Preliminary results from the study of cold and thermal waters
No full textGeochemistry of fluids and CO2 output in the southern Apennine (Italy): Preliminary results for cold and thermal waters
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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