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Mesozoic tectono-sedimentary evolution of Rocca Busambra in Western Sicily
No full textThe Rocca Busambra ridge in western Sicily is a shallow to pelagic Meso-Cenozoic carbonate structural unit
of the Sicilian fold and thrust belt with a variety of tectono-sedimentary features. Palaeofaults, unconformities
(buttress unconformity, onlap, downlap), a network of neptunian dykes with several infilling generations, several
large hiatuses, different facies and lateral facies changes, and erosional submarine and subaerial surfaces are
observed.
Detailed fieldwork and structural analyses have indicated the occurrence of fault planes with different
orientations. These data, combined with facies studies and physical-stratigraphy analyses, allow for the
distinction of different depositional regions. A lateral change from an open-marine carbonate platform with a
stepped fault margin (located in the westernmost sector) to a deeper basinal depositional setting in the east, in
the context of an upper slope scalloped margin and base-of-slope systems with talus breccias, is envisaged
here. Extensional to transtensional tectonic pulses punctuated the sedimentary evolution during Early Toarcian,
Late Jurassic, Early Cretaceous, Late Cretaceous, and Early Miocene times. The collected data show that most
fault planes have preserved their original orientations throughout the reactivation processes. The reconstructed
Meso-Cenozoic tectono-sedimentary evolution is closely related to the late syn-rift and post-rift tectonic evolution
of the Tethyan continental margin
Climatically versus tectonically driven Quaternary incision rates in the Guadix Basin (Betic Cordillera, Southeastern Spain).
No full textAnálisis de la erosión diferencial en el pleistoceno superior para las subcuencas de Guadix y Baza.
No full textErosion rates in the Guadix-Baza basin have been calculated drawing on a volumetric estimation of sediment loss by river erosion since the late Pleistocene. On this purpose we have performed a reconstruction of the glacis surface dated in 42.6 ka and defined by a calcrete layer that capes the basin infilling. In order to support this age, we presented new 14C radiometric data of three travertine platforms formed later to the beginning of the river entrenchment in the basin and a U/Th dating of a lower calcrete situated some meters below the glacis surface. By comparing the reconstructed geomorphic surface and the present day topography we have calculated the volume of sediment lost by hidric erosion in the entire basin. The resulting erosion rates are between 4.28 and 6.57 m3ha-1yr-1. Individual erosion rates for Guadix and Baza sub-basins (11.80 m3ha-1yr-1 and 1.77 m3ha-1yr-1 respectively) suggest different stages of drainage pattern evolution in both sub-basins. We attribute part of the lower values obtained in the Baza sub-basin as related to the down-throwing due to very recent activity along the Baza fault
Características petrográficas y datación U/Th de una calcreta laminar Cuaternaria: Implicaciones de la captura de la Cuenca de Guadix-Baza por el río Guadalquivir.
No full textThe Guadix topographic depression is a Neogene-Quaternary basin located in the central sector of the Betic Cordillera at the boundary between the South Iberian margin and the Alboran domain. This topographic depression is a plateau with an average elevation of 1000 m in the northern limb of the Sierra Nevada range. The continental deposits infilling the Guadix basin span time from the late Tortonian to the Pleistocene, when a laminar calcrete developed on fine to coarse-grained fluvial and lacustrine deposits. Four coeval subsamples from the top laminae of the calcrete were collected and dated by the U/Th method. The resulting date is 42.6 ± 5.6 ka, which indicates the minimum age for the cessation of active sedimentation in the Guadix basin. We envisage the capture of the Pliocene-Pleistocene endorheic Guadix basin by the Guadalquivir River after 42 ka as the main factor triggering the formation of the present-day eroded landscape. After the capture, the combination of climatic (wet periods), lithological (soft and loose sediments), and topographic (high average altitude) features allowed the development of the present-day entrenched drainage pattern
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
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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