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Paleogeografia mesozoica ed evoluzione tettonosedimentaria della dorsale Narnese-Armerina (Appennino Centrale): rilevamento geologico, biostratigrafia, analisi di facies
Full text linkUn progetto di cartografia geologica di dettaglio (scala 1:10.000) ha coinvolto circa 135 kmq della Dorsale Narnese-Amerina (Appennino centrale). Il lavoro di terreno è stato svolto avvalendosi delle metodologie tradizionali del rilevamento geologico, alle quali però è stato associato il riconoscimento di particolari caratteri stratigrafico-sedimentologici tali da permettere la definizione di peculiari contesti deposizionali mesozoici tipici dell'Appennino Umbro-Marchigiano-Sabino. La carta geologica e la ri-definizione della litostratigrafia dell'area analizzata sono stati i primi prodotti del progetto. A questi è susseguita la ricostruzione della paleogeografia mesozoica della Dorsale Narnese-Amerina. Sono stati riconosciuti numerosi elementi morfostrutturali ereditati dal rifting del Giurassico Inferiore. Questa fase estensionale smembrò l'estesa paleo-piattaforma del Calcare Massiccio e, per quanto riguarda il Dominio Umbro-Marchigiano-Sabino, causò l'annegamento della fabbrica bentonica e provocò un tipico assetto ad alti e bassi strutturali intrabacinali. Numerosi blocchi di footwall delle faglie giurassiche caratterizzano il settore in analisi, e il riconoscimento è stato possibile mediante l'analisi delle paleoscarpate sottomarine in quanto le tipiche successioni condensate di alto strutturale non affiorano per erosione o per tettonica. Una particolarità è rappresentata da blocchi di Calcare Massiccio (diametro > 100 m) inglobati in successioni bacinali, che hanno portato alla deposizione di facies ad affinità condensata in un contesto deposizionale puramente bacinale. Sono state riconosciute torbiditi carbonatiche con materiale bentonico intercalate in pelagiti di età post-Pliensbachiano del settore Amerino, permettendo di porre dei vincoli sulla ricostruzione paleogeografica dell'Appennino centrale e sulla definizione delle influenze esercitate dagli elementi morfostrutturali sulla deposizione di materiale neritico esportato dalla Piattaforma Carbonatica Laziale-Abruzzese. Durante il Cretaceo Inferiore alcune discontinuità giurassiche sono state ri-utilizzate da una neo-identificata tettonica estensionale post-rift. Le maggiori evidenze dell'attività delle faglie dirette cretacee sono: i) contatti stratigrafici inconformi tra il Calcare Massiccio e depositi del Cretaceo inferiore sommitale (Marne a Fucoidi) a causa del ringiovanimento di margini giurassici; ii) la deposizione di brecce sin-tettoniche intercalate nelle pelagiti cretacee e poggianti in discordanza su scarpate di faglia sottomarine; iii) slumps, nicchie di distacco e faglie sin-sedimentarie che caratterizzano il top della Maiolica. E' stato operato anche un confronto tra l'Appennino Umbro-Sabino e il Sud-Alpino per definire l'influenza delle strutture giurassiche sullo sviluppo delle faglie dirette cretacee. Con il coinvolgimento del settore Narnese-Amerino nelle deformazioni compressive mioceniche ed estensionali post-orogeniche (Pliocene), è stato possibile riconoscere come le discontinuità ereditate dal Mesozoico abbiano controllato la propagazione delle faglie cenozoiche. In particolare, i sovrascorrimenti e le rampe laterali/faglie di strappo legati alla strutturazione dell'Appennino tagliarono i margini giurassici e cretacei senza riattivazione dei piani ereditati. Il rapporto tra paleogeografia mesozoica e orogenesi non poteva escludere gli olistoliti di Calcare Massiccio, argomento questo del tutto nuovo. A causa della differente reologia tra i blocchi di calcari peritidali e le pelagiti nelle quali sono inglobati, sono stati riconosciuti contatti tettonici su originari contatti stratigrafici in quanto gli olistoliti non sono stati in grado di descrivere pieghe della stessa lunghezza d'onda delle unità bacinali pelagiche. Infine le faglie dirette plioceniche non riutilizzarono le superfici di discontinuità mesozoiche in quanto ruotate dai sovrascorrimenti, ma ne sfruttarono solo lo strike.A detailed geological mapping project (scale 1:10.000) of about 135 kmq involved the Narni-Amelia Ridge (Central Apennines). During the field-work were used the traditional methodologies of the field mapping associated with the identification of characteristic stratigraphic-sedimentological features that allow to define peculiar Mesozoic depositional settings. The first products of the project were the 1:10.000 scale geological map and the re-definition of the lithostratigraphy of the study area. About the paleogeography, several morphostructural elements inherited by the Early Jurassic rifting stage were recognized. This extensional stage dismembered the vast Calcare Massiccio paleo-platform, and the drowning of the benthic factories led to the development of two main sedimentary environments: pelagic carbonate platforms (PCPs) and basins. The Early Jurassic rift architecture is documented by facies and thickness variations of the Jurassic-Lower Cretaceous post-rift succession. Several footwall-blocks of the Jurassic normal faults characterize the Narni-Amelia Ridge. Although the PCP-top successions are not exposed due to post-Jurassic faulting and modern erosion, highly distinctive facies associations define the escarpment margins of these platforms and the adjacent hangingwall-block successions that onlap them, which often embed gravity-driven deposits including rock-fall megaclastics. Fine-grained calcarenites made of shallow water-derived material were found embedded in post-Pliensbachian deposits of the basin-fill succession in the Amelia area. This occurrence is unexpected as these deposits postdate the drowning of the local Calcare Massiccio carbonate platform, which suggests provenance from the Latium-Abruzzi Platform. This provides new evidence for restoring the Jurassic paleogeography of Central Apennines, and for deciphering the itineraries of resedimented carbonate sands from this relatively distant source-area. A newly-identified, post-rift, extensional tectonic affected the Early Jurassic inherited structures during the Early Cretaceous. Evidence for this extensional tectonic phaseare: i) the unconformable contact between the Marne a Fucoidi Fm. (Aptian-Albian) and the Hettangian shallow-water carbonates of the Calcare Massiccio Fm., as a result of rejuvenation and erosion of the Early Jurassic margin of the Amelia intra-basinal high; ii) the occurrence of syn-tectonic breccias embedded in Cretaceous pelagites and locally resting on the submarine fault escarpments; iii) the presence of slumps, scars and syn-sedimentary faults at the top of the Maiolica Fm (Tithonian-early Aptian). Due to the stratigraphic, sedimentological and paleotectonic similarities with the Southern Alps, the two sectors (Narni-Amelia Ridge vs. Ballino area) were compared. The aim of this work was to understand the influence on inherited Jurassic structures on the development of Early Cretaceous extensional faults in two different paleogeographic domains of Italy, albeit with a comparable tectono-sedimentary evolution. During the involvment in Miocene orogenic deformations of the Narni-Amelia Chain, the Jurassic structural highs became part of the hangingwall-blocks of thrusts. Their margins were displaced by frontal thrusts and lateral ramps/tear faults, but not re-activated as usually described in literature. One arresting feature is represented by the behaviour of the Calcare Massiccio blocks during the compressive deformations. In fact, the Calcare Massiccio olistoliths locally developed shear contacts with the embedding pelagic units, due to the contrasting mechanical behavior of the two lithologies when subjected to folding. Last, Pliocene extensional faults apparently exploited the strikes of the rotated pre-orogenic margins
Subsidence history from a backstripping analysis of the Permo-Mesozoic succession of the Central Southern Alps (Northern Italy)
No full textSeven tectonic subsidence curves, based on outcrop data, have been calculated in order to constrain the geodynamic evolution of the Permian-Mesozoic sedimentary succession (up to 10 km thick) of the Central Southern Alps basin (Italy). The analysis of the tectonic subsidence curves, covering a time span of about 200 Ma, allowed us to quantify the subsidence rates, to document the activity of syndepositional fault systems and calculate their slip rates. Different stages, in terms of duration and magnitude of subsidence-uplift trends, have been identified in the evolution of the basin. The fault activity, reconstructed by comparing subsidence curves from adjacent sectors, resulted as highly variable both temporally and spatially. Strike-slip tectonics was coeval to Permian sedimentation, as suggested by the strong differences in the subsidence rates in the sections. The evolution and subsidence rates suggest a continental shelf deposition from Early Triassic to Carnian, when subsidence came to a stop. A rapid resumption of subsidence is observed from the Norian, with a subsidence pulse in the Late Norian, followed by the regional uplift, in the Late Rhaetian. The following Early Jurassic subsidence is characterized by tectonic subsidence similar to that of the Norian. The Norian and Early Jurassic pulses were characterized by the highest slip rates along growth faults and are identified as two distinct tectonic events. The Norian-Rhaetian event is tentatively related to transtensional tectonics whereas the Early Jurassic event is related to crustal extension. The Early Jurassic subsidence records a shift in space an time of the beginning of the extensional stage, from Late Hettangian to the east to Late Pliensbachian-Toarcian to the west. From the Toarcian to the Aptian, the curves are compatible with regional thermal subsidence, later followed (Albian-Cenomanian) by uplift pulses in a retrobelt foreland basin (from Cenomanian onward)
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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