1,720,980 research outputs found
La distensione tetidea ed il suo controllo sulle strutture compressive del sistema appenninico-maghrebide: l'esempio dei Monti delle Madonie (Sicilia centro-settentrionale)
No full textL'assetto tettonico dei Monti delle Madonie (Sicilia centro-settentrionale) è caratterizzato dalla presenza di un importante lineamento orientato NNW-SSE che si estende per circa 20 Kkm da Gratteri fino a M. Mufara, individuando un settore orientale, dove affiorano le successioni della piattaforma carbonatica panormide, ed un settore occidentale, dove affiorano i depositi del bacino imerese. I risultati di uno studio stratigrafico-strutturale consentono di definire il ruolo svolto da questo lineamento tettonico dal Trias superiore al Pliocene. In particolare, l'analisi cinematica mostra che il lineamento corrisponde alla rampa òlaterale di un sovrascorrimento, attivo durante l'intervallo Miocene medio-Pliocene, lungo il quale le unità panormidi si sono sovrapposte tettonicamente alle unità imeresi. L'analisi stratigrafica ed i rapporti fra le facies delle successioni meso-cenozoiche mostrano che la rampa laterale mio-pliocenica si è impostata su una pre-esistente struttura attiva già dal Trias superiore. Durante l'intervallo Trias superiore-Cretaceo questa struttura ha agito come faglia diretta e/o transtensiva, individuando aree a sedimentazione neritica ed aree a sedimentazione pelagica. A partire dal Cretaceo superiore la struttura distensiva è stata riutilizzata come faglia di trasferimento fra sistemi di faglie dirette orientate W-E che si originano probabilmente in risposta ai movimenti convergenti orientati N-S ed attivi nella futura area mediterranea durante l'intervallo Cretaceo superiore-Oligocene
The effects of post-orogenic extension on different scales: an example from the Apennine-Maghrebide fold-and-thrust belt, SW Sicily
No full textMany structures produced under one single deformation regime, namely extensional, contractional or strike-slip, exhibit remarkable geometrical analogies when analysed at different scales. By contrast, field examples that illustrate the scale effects on structures resulting from superimposed deforma- tions, which were produced under different tectonic regimes, are rare. Yet the change from contraction to extension is known to occur often in the most thickened portions of the continental crust. The Apennine–Maghrebide fold-and-thrust belt of Sicily shows many examples of post-orogenic extensional deforma- tions. Composite structures, resulting from late normal faults that offset folds and thrusts, are observed at four different scales, from regional to mesoscopic, in the south-western portion of Sicily and in the adjacent Isle of Favignana. The recognized analogies in the geometry of these composite structures may provide a key for the interpretation of the features of regional structures, whose deep geometry is often poorly constrained. Moreover, comparison of normalized displacements accommodated by contractional and extensional faults of different scales indicates that self-similarity is not unique to structures produced under single tectonic regimes
Composite structures produced during negative inversion: an example from the Isle of Favignana, Egadi Islands
No full textMany structures produced under one given deformation regime, namely extensional, contractional or strike-slip, exhibit remarkable geometrical analogies when analysed at different scales. By contrast, field examples that illustrate the scale effects on structures resulting from superimposed deformations are rare. Yet, the change from contraction to extension, known in the literature as negative tectonic inversion, occurs often in the most thickened portions of the conti- nental crust and lithosphere. The Apennine-Maghrebide fold-and- thrust belt of Sicily and adjacent minor islands shows many exam- ples of post-orogenic extensional deformation. Composite structures, resulting from late normal faults that offset folds and thrusts, are observed at two different scales, from macroscopic to mesoscopic, in the Isle of Favignana, the major island of the Egadi group. The anal- ogies recognised in the geometry of these composite structures may provide a key for the interpretation of the features of macroscopic structures, whose deep geometry is often poorly constrained. More- over, comparison of normalised displacements accommodated by contractional and extensional faults of different scales indicates that self-similarity is not unique to structures produced under single tectonic regimes
Neogene deformations of Northern Sicily, and their implications for the geodynamics of the Southern Tyrrhenian Sea margin
No full textThe character of recent deformations along the southern Tyrrhenian Sea margin is controversial, in that it is explained either in terms of N-S convergence, or in terms of N-S extension. At odds with these extensional or contractional interpretations, analysis of kinematic data from NW-SE trending faults in northern Sicily and in the Egadi Islands reveals a dominantly right-lateral strike-slip character. Most faults are recent, but evidence is also present for an ancient fault, the Gratteri-Mt. Mufara Line, that was recently reactivated. Based on integration of these new data with available information on adjacent offshore structures, we propose that the southern Tyrrhenian Sea margin corresponds to a E-W trending dextral shear zone, namely to a strike-slip duplex, that was developed in response to a horizontal, NW-SW oriented contractional stress field
Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy
No full textThe geodynamics of the southern Tyrrhenian Sea margin as revealed by integrated geological, geophysical and geodetic data
No full textThe recent and present-day deformation field of the southern Tyrrhenian Sea margin, as revealed from integrated geophysical, structural and space geodesy data, is characterised by subhorizontal NW-SE directed shortening and SW-NE directed extension. This def- ormation was mainly accommodated by development of an E-W trending, complex fault system that has the geometrical features of a strike-slip duplex, and that is here indicated as the Southern Tyr- rhenian Strike-Slip Duplex (STSSD). Most faults within the STSSD are recent. There are, however, local examples of ancient faults that were repeatedly reactivated through time, such as the Gratteri-Mt. Mufara Line. Structural measurements on these exposed fault sur- faces help constrain the kinematics of coeval structures offshore, and make it possible to interpret the latter as transtensional, rather than purely extensional structures, as proposed by many authors. The results of our study ultimately shows the effectiveness of an integrated, multidisciplinal approach in the study of active deforma- tion margins
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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