1,721,140 research outputs found
Tectonic control on the evolution of depositional systems in a fossil, marine foreland basin: Example from the SE Austral Basin, Tierra del Fuego, Argentina
No full textCombined research on the structural and stratigraphic evolution of the southeastern Austral Basin identifies three major depositional systems strongly influenced by the tectonic stages of the Fuegian Andes between the Late Cretaceous and the Miocene. During orogenic growth, a submarine ramp system characterized by oblique progradational clinoforms with transverse sediment dispersal, formed adjacent to the deformation front in the wedge-top or proximal foredeep. In moments when the tectonic load and flexural subsidence were reduced, this system was replaced by a progradational-aggradational system with oblique to sigmoidal clinoforms. This occurred during a short span in the middle Eocene, but especially and definitively after contractional deformation ceased in the early Miocene. The third depositional system was long lived, and comprised axial turbidite channel systems located at the clinoform bases, which re-routed sediment toward the deeper foredeep of the western Malvinas Basin. Distinct facies types develop in each depositional system, and their recognition allows evaluating sediment fairways in the foreland basin system.Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Olivero, Eduardo Bernardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin
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
On the high scientific quality of early research on strain and deformation fabrics (1835-1908)
Get PDFHigh-quality research developed during the 19th century established the foundations of rock strain investigations. Careful observation and description of rock fabrics and deformed objects in rocks allowed early researchers to obtain mathematical expressions that are still used today to quantify strain. Thus, in a span of a few decades, and applying basic scientific methodology, these researchers developed the concept of the strain ellipsoid, defined mathematically the difference between constant-volume and volume-loss deformation, constructed the basic equations that define pure and simple shear deformation, and discovered the mechanism of pressure-solution deformation. These advances were fundamental to seminal works on strain analysis and deformation fabrics in the mid-20th century. However, they are rarely addressed in modern studies, which suggests a lack of awareness among current researchers. In order to bring attention to these landmarks of strain research, I provide a historical review of the high standards of analysis that led to the definition of the fundamental equations and concepts on strain during the 19th century.Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin
Geometry and kinematics of the Fuegian thrust-fold belt, southernmost Andes
Get PDFPublished balanced structural interpretations of the Fuegian thrust-fold belt (southernmost Andes) fail to address aspects such as basement shortening in the thrust-fold belt or its structural connection with the central belt of the orogen. We tackle this deficiency by constructing four serial balanced cross sections based on surface geologic information, 2-D reflection seismic lines, and well logs, which depict the first-order structural geometry and kinematics from the thrust front to the internal thrust-fold belt. The interpretation reveals three main tectonostratigraphic packages separated by major detachments: basement (Paleozoic-Upper Jurassic), Cretaceous, and Paleogene, all variably involved in thrusting along strike. Minimum shortening in the Paleogene cover ranges between 16% and 43%, and significant style changes are observed across and along the thrust wedge. We show that basement thrust sheets have a major role in the construction of the thrust-fold belt; some of them were emplaced below the thrust front during late Oligocene or early Miocene times. The kinematic evolution of the thrust-fold belt indicates that the active detachments depended on the existence of high pore pressure to propagate forward. Our model shows that this pore pressure buildup was controlled by overburden, mean rock impermeability, and strain rate; the variable interaction among these factors controlled the propagation and style of the thrust wedge.Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Rodríguez Arias, Leonardo. Ypf S. A.; ArgentinaFil: Atencio, Mario R.. Ypf S. A.; Argentin
Thrust-fold belt kinematics and orogenic growth in Tierra del Fuego, Argentina: implications of backthrusting for critical Coulomb wedge development
Get PDFAnalysis of balanced cross-sections and of the chronostratigraphy of the deformed foreland basin successions allows to solve the structural kinematics of the eastern Fuegian thrust-fold belt. Based on the Coulomb wedge theory, we propose a chronologically and geometrically well-constrained growth history for the frontal Fuegian Andes orogen. The mountain front behaved in a critical manner during the Early Eocene, characterized by forward thrusting. The wedge became subcritical after that, until renewed forward propagation of the thrust front in the Early Miocene. The long period as a subcritical wedge enhanced retrodeformation, recorded by out-of-sequence thrusting and backthrusting. We suggest that backthrusts should be considered an important mechanism for accommodating shortening in subcritical orogenic wedges.Fil: Torres Carbonell, Pablo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Dimieri, Luis Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Olivero, Eduardo Bernardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin
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