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Syn-orogenic extensional pulses within the contractional history of thrust wedge. The Val di Lima low-angle normal fault case study, Northern Apennines, Italy
No full textStructure of a normal seismogenic fault zone in carbonates: The Vado di Corno Fault, Campo Imperatore, Central Apennines (Italy)
Get PDFThe Vado di Corno Fault Zone (VCFZ) is an active extensional fault cutting through carbonates in the Italian Central Apennines. The fault zone was exhumed from ∼2 km depth and accommodated a normal throw of ∼2 km since Early-Pleistocene. In the studied area, the master fault of the VCFZ dips N210/54° and juxtaposes Quaternary colluvial deposits in the hangingwall with cataclastic dolostones in the footwall. Detailed mapping of the fault zone rocks within the ∼300 m thick footwall-block evidenced the presence of five main structural units (Low Strain Damage Zone, High Strain Damage Zone, Breccia Unit, Cataclastic Unit 1 and Cataclastic Unit 2). The Breccia Unit results from the Pleistocene extensional reactivation of a pre-existing Pliocene thrust. The Cataclastic Unit 1 forms a ∼40 m thick band lining the master fault and recording in-situ shattering due to the propagation of multiple seismic ruptures. Seismic faulting is suggested also by the occurrence of mirror-like slip surfaces, highly localized sheared calcite-bearing veins and fluidized cataclasites. The VCFZ architecture compares well with seismological studies of the L'Aquila 2009 seismic sequence (mainshock MW 6.1), which imaged the reactivation of shallow-seated low-angle normal faults (Breccia Unit) cut by major high-angle normal faults (Cataclastic Units)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Extensional deformation structures within a convergent orogen: The Val di Lima low-angle normal fault system (Northern Apennines, Italy)
No full textA low-angle extensional fault system affecting the non metamorphic rocks of the carbonate dominated
Tuscan succession is exposed in the Lima valley (Northern Apennines, Italy). This fault system affects the
right-side-up limb of a kilometric-scale recumbent isoclinal anticline and is, in turn, affected by superimposed
folding and late-tectonic high-angle extensional faulting.
The architecture of the low-angle fault system has been investigated through detailed structural
mapping and damage zone characterization. Pressure-depth conditions and paleofluid evolution of the
fault system have been studied through microstructural, mineralogical, petrographic, fluid inclusion and
stable isotope analyses. Our results show that the low-angle fault system was active during exhumation
of the Tuscan succession at about 180C and 5 km depth, with the involvement of low-salinity fluids.
Within this temperature - depth framework, the fault zone architecture shows important differences
related to the different lithologies involved in the fault system and to the role played by the fluids during
deformation. In places, footwall overpressuring influenced active deformation mechanisms and favored
shear strain localization.
Our observations indicate that extensional structures affected the central sector of the Northern
Apennines thrust wedge during the orogenic contractional history, modifying the fluid circulation
through the upper crust and influencing its mechanical behavior
Anatomy and paleofluid evolution of laterally restricted extensional fault zones in the Jabal Qusaybah anticline, Salakh arch, Oman
Get PDF© 2016 Geological Society of America. The E-W-trending Jabal Qusaybah anticline, at the western termination of the Salakh arch, Oman Mountains, is characterized by a complex fault network that developed in layered Cretaceous carbonates. This network includes NE-SW left-lateral, N-S extensional, and subordinate E-W extensional fault zones. The N-S-striking extensional faults zones are roughly perpendicular to the fold axis and are best developed in the longitudinally bulged central sector of the anticlinal crest. They are likely due to along-strike outer-arc extension associated with positive fault inversion and salt migration. These extensional fault zones are confined within, and locally abut, major NE-SW left-lateral strike-slip fault zones. Extensional fault displacements range between a few decimeters and ~60 m, whereas the maximum exposed trace lengths range between a few meters and ~800 m. Narrow (~1-15-cm-thick) cataclastic fault cores are surrounded by vein-dominated damage zones as thick as tens of meters. Moreover, fault zones show widespread evidence for substantial dilation in the form of (1) dilation breccias, (2) infilling by large columnar calcite crystals and aggregates, and (3) centimeter- to meter-thick veins. Dilation breccias and calcite infillings are primarily localized at fault tips, fault overlaps, and interaction zones between strike-slip and extensional fault segments. Displacement profiles along the N-S-striking extensional fault zones indicate that they are one order of magnitude shorter than values predicted by most published displacement-length scaling laws. By analyzing fault abutting geometries, detailed vein relative chronology, d13C and d18O signatures, and fluid inclusion data from calcite veins and calcite fault infillings, we propose a model whereby a deep-seated, regionally sized, left-lateral strike-slip fault system that was active during anticline growth inhibited the lateral propagation of late-stage transversal extensional fault zones. Our findings show that, in this geological setting, the structural position, rather than fault displacement, is the parameter controlling the location of the more dilatants (and permeable) fault segments. Results of the present work suggest that fault intersections may be more useful than fault throw for predicting zones of enhanced vertical fluid flow in structurally complex carbonate reservoirs.sponsorship: This work is part of a joint research project between Parma and KU Leuven universities, funded by Shell Global Solutions International. We are grateful to Shell for releasing this material for publication. We are also grateful to L. Barchi, A. Comelli, and H. Nijs for support with thin section preparation. We warmly thank F. Mondino (formerly at Shell) for the enthusiastic support she gave to the early stages of this project. The manuscript strongly benefited from discussions with L. Bazalgette, A. Koopman, and P. Richard. A. Koopman is also thanked for his accurate revision of an early manuscript version. Associate Editor E. Tavarnelli, and the two reviewers F. Agosta and F. Calamita, are kindly thanked for their constructive criticism and comments. (Shell Global Solutions International)status: Publishe
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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