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Extension of thickened continental crust, from brittle to ductile deformation: examples from Alpine Corsica and Aegean Sea
No full textJCR Journalope
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
Insights from the Apennines metamorphic complexes and their bearing on the kinematics evolution of the orogen
No full textThe Apennine belt represents a typical orogenic segment of the western Mediterranean,
characterized by the tectonic convergence between European and Africa plates after oceanic subduction.
Both oceanic- and continent-derived metamorphic complexes, considered as the remnants
of the subduction-exhumation cycle, crop out in the inner sectors of the Apennine belt, where
extensional deformation has dominated since the Early Oligocene. We review the available structural,
metamorphic and geochronological data coming from these metamorphic complexes in order
to provide a kinematics reconstruction accounting for the tectono-metamorphic evolution of the
Apennines, from oceanic subduction to final extensional reworking. During the Eocene, oceanic
rocks were progressively subducted down to eclogite-facies conditions following a subductiontype
metamorphic gradient. The transition from oceanic- to continental-subduction was coeval
with a transition from subduction-type to Barrovian-type metamorphic gradient. Continental collision,
at the Eocene–Oligocene boundary, post-dated the syn-orogenic exhumation of HP-rocks
and was synchronous with the onset of post-orogenic extension in the hinterland domains.
Extensional deformation migrated to the east, following the forelandward migration of the
thrust system at the trench. The concomitance of extension and compression is here related to
fast rollback of the subducting plate and delamination of the lithospheric mantle below the subducted
continental crust. Implications on how the subduction tectonics, syn-orogenic exhumation
and post-orogenic extension could have controlled the circulation of HP-rocks in the developing
Apennines are also discussed
Anatomy of the Cycladic Blueschist Unit on Sifnos Island (Cyclades, Greece)
No full textSince 35 Ma, the kinematics of the Aegean domain has been mainly controlled by the southward retreat of the African slab, inducing back-arc extension. The main structures and associated kinematics are well constrained, but the kinematics of deformation before 35 Ma, coeval with the exhumation of blueschists and eclogites of the Cycladic Blueschist Unit, is still poorly understood. The earlier Eocene syn-orogenic evolution is strongly debated and very different geometrical interpretations and kinematic histories have been proposed in the literature. This study focuses on the high-pressure and low-temperature (HP-LT) parageneses spectacularly exposed and well preserved on Sifnos Island. The new field work provides new structural constraints on the tectonic history of HP-LT units generated in the subduction zone during the Eocene. It further shows how lithological heterogeneities localize strain within an accretionary wedge and how the localisation of strain evolves through time during exhumation. We show, through new geological and metamorphic maps, cross-sections and analyses of kinematic indicators, that Sifnos is characterized by shallow-dipping shear zones reactivating weak zones due to competence contrasts or earlier tectonic contacts. Structures and kinematics associated with these shear zones, show a top-to-the-N to −NE ductile deformation. The lower part of the tectonic pile shows a downward gradient of shearing deformation and is actually a thick top-to-the-NE shear zone, which we name the Apollonia Shear Zone. Through time shearing deformation tends to localize downward, leaving the upper part of the subduction complex preserved from late deformation. The present-day shape and topography of the island is largely controlled by late brittle faults reworking the earlier ductile shear zones. Comparing with the nearby island of Syros, we propose a new tectono-metamorphic evolution of the Cycladic Blueschist Unit, which partly explains the different degrees of retrogression observed on the Cycladic Islands
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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