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FATICA SU UN VIADOTTO STRADALE A TRAVATA CONTINUA
No full textFATICA SU UN VIADOTTO STRADALE A TRAVATA CONTINUA
// Collana STUDI E RICERCHE - Dipartimento di ingegneria strutturale e geotecnica / Università degli studi di Roma "La Sapienza". ROMA: Esagrafica srl (Italy)
Comment on: Carbonatites in a subduction system: the Pleistocene alvikites from Mount Vulture (Southern Italy)by d'Orazio et al., (2007)
No full text[D'Orazio, M., Innocenti, F., Tonarini, S., Doglioni, C., 2007. Carbonatites in a subduction system: the Pleistocene alvikites
from Mt. Vulture (southern Italy). Lithos 98, 313–334] describe a new finding of alvikite Ca-carbonatite at Vulture. They stress its
importance as being the first carbonatite to be discovered in a subduction environment. They suggest that this rock is different from
the other Italian carbonatites, considered as ‘rocks sharing a carbonatitic affinity’, which are radiogenic and chemically diluted by
addition of sedimentary limestone. They note that Vulture ‘alvikite’ is not diluted and is very unradiogenic with respect to other
Italian carbonatites. However, they maintain that Vulture ‘alvikite’ carbonate is derived from subducted limestones. We present an
account of the field relationships relating to the above-mentioned rocks, setting the geological and petrographic records straight and
describing pyroclastic rocks. We did not find that these rocks are formed from alvikite dykes or lava, but instead recognised them to
be a continuous blanket of ‘flaggy’, welded tuff. We found that the rocks consist of physically separated melilitite and carbonatite
juvenile lapilli settled into a carbonatite ash matrix form the rock. We disagree with the geochemical interpretation of the rock by
[D'Orazio, M., Innocenti, F., Tonarini, S., Doglioni, C., 2007. Carbonatites in a subduction system: the Pleistocene alvikites from
Mt. Vulture (southern Italy). Lithos 98, 313–334], and are particularly concerned by their conclusion of its carbonate origin. We
remark on the rock's geodynamic assignment in the frame of an extensional tectonic setting, also referring to the other Italian
carbonatite occurrences. We reject any ad hoc modified subduction as a direct source of Vulture and Italian carbonatites.
© 2007 Elsevier B.V. All rights reserved
Il vulcanismo monogenico medio-pleistocenico della conca di Carsoli (L’Aquila).
No full textThe volcanic field is comprised of several Upper Pleistocene small tuff cones, tuff rings and maars (531 ka), aligned along a NNW-SSE normal fault of regional meaning. Most of the deposits are directly related to vent structures and preserve signs of primary proximal origin consisting of high-energy structures, welded lapilli and ballistic impacts. Characteristic sequences of vent coring eterolithic breccias, dry lapilli-ash surges of high-temperature and wet surges of ash-lapilli tuff are exposed and found in well coring. Juvenile fragments consist of plastically moulded lapilli, essentially composed of diopside, phlogopite, leucite, K-feldspar, apatite and immersed in a turbid micro-cryptocrystalline matrix of Ca-carbonate. Lapilli shape indicates that they agglutinated and quenched when still hot plastic. Silicate glass shards are present and have typical cuspate wedges produced by bubbles expansion and disruption during magmatic activity sustained by juvenile gases. A late phreato-strombolian phase builted several tuff-rings and cones. At Oricola - Carsoli - Rocca di Botte - Camerata Nuova volcanic field, juvenile fragments and tuffs range from phonolitic-foidite to foiditic-carbonatitic to carbonatite s.s. The latter forms small pyroclastic flows and surge deposits. Geological context, age, mineralogy and petrology are germane with the near Grotta del Cervo occurrence and are consistent with the carbonatitic-kamafugitic suite of Italy. This new carbonatitic outcrop, that joins the increasing number of Italian carbonatites, puts Italy in a relevant place for what concerns carbon-rich mantle magmatism occurrences. Actually, the six extrusive carbonatites and the intrusive one so far reported, represent one of the largest concentrations of such a kind of rocks all over the world
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
Is there a mantle plume below Italy?
No full textSome of the most diverse igneous rocks found on Earth occur along the length of Italy and in many of the islands in the southeastern Tyrrhenian Sea, all the result of Cenozoic magmatism. Magmas extremely rich in alkalis, particularly potassium, and many undersaturated with respect to silica, were erupted, as well as others of calc-alkalic affinity . Their origin has been the subject of heated debate, and there is still no general consensus about how they formed. Most attribute them to subduction-related processes (Beccaluva et al. 2004, for a review); others consider them to be the result of within-plate magmatism [e.g., Vollmer, 1976; Lavecchia and Stoppa, 1996]. Still others consider magmatism the result of a deep, mantle upwelling within a slab window coupled with mixing between isotopically different reservoirs [Gasperini et al., 2002]
Introduction to the special Issue, insights on carbonatites and their mineral exploration approach: A challenge towards resourcing critical metals
Full text linkPopulation growth and technological progress in the last 50 years have resulted in the global demand for mineral resources increasing by 400% since 1970, and it is further expected to almost double by 2050. This context forecasts a never-seen-before market for some specific mineral commodities, termed critical metals. The resource and supply flow of critical metals would be decisive for the economic well-being of economies in near future. Carbonatites are the most prospective host rocks for Rare Earth Elements (REEs), which constitute some of the most important critical elements. This special issue aims to contribute to the debate on understanding the genesis of carbonatites and their prospectivity for REEs (including exploration strategies), by presenting a wide variety of studies on carbonatites from around the globe
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
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