3 research outputs found

    Presutti sindaco di Napoli

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    Per una serie complessa di ragioni Errico Presutti (1870-1949)   stato praticamente dimenticato. Eppure l’allievo di Giorgio Arcoleo, di Federico Persico (ma anche di Lodovico Mortara) nell’Ateneo partenopeo, il sindaco di Napoli tra il 1917 e il 1919, il deputato amendoliano e poi aventiniano, dichiarato decaduto nel 1926 e per questo escluso anche dalla cattedra nel 1927 appare avere un rilievo che deve essere ricordato sia nell’istituzione parlamentare sia in ambito accademico proprio nel momento di difficolt  degli ordinamenti rappresentativi. Il convegno articolato tra Roma (Camera dei deputati) e Napoli (Federico II) vuole approfondire il suo contributo alla scienza giuspubblicistica nel periodo della transizione allo stato di massa, la sua azione come amministratore pubblico e come deputato liberaldemocratico. Organizzatore Fondazione “Paolo Galizia-Storia e Libert ”, con la collaborazione dell’Universit  di Roma “La Sapienza” (Master in Istituzioni parlamentari “Mario Galizia” per consulenti di Assemblea) e dell’Universit  Federico II di Napoli (Facolt  di Giurisprudenza)

    Origin and evolution of Cenozoic magmatism of Sardinia (Italy). A combined isotopic (Sr-Nd-Pb-O-Hf-Os) and petrological view

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    The Cenozoic igneous activity of Sardinia is essentially concentrated in the 38-0.1 Myr time range. On the basis of volcanological, petrographic, mineralogical, geochemical and isotopic considerations, two main rock types can be defined. The first group, here defined SR (Subduction-Related) comprises Late Eocene-Middle Miocene (~ 38-15 Ma) igneous rocks, essentially developed along the Sardinian Trough, a N-S oriented graben developed during the Late Oligocene-Middle Miocene. The climax of magmatism is recorded during the Early Miocene (~ 23-18 Ma) with minor activity before and after this time range. Major and trace element indicators, as well as Sr-Nd-Pb-Hf-Os-O isotope systematic indicate complex petrogenetic processes including subduction-related metasomatism, variable degrees of crustal contamination at shallow depths, fractional crystallization and basic rock partial melting. Hybridization processes between mantle and crustal melts and between pure mantle and crustally contaminated mantle melts increased the isotopic and elemental variability of the composition of the evolved (intermediate to acid) melts. The earliest igneous activity, pre-dating the Early Miocene magmatic climax, is related to the pushing effects exerted by the Alpine Tethys over the Hercynian or older lower crust, rather than to dehydration processes of the oceanic plate itself. The second group comprises volcanic rocks emplaced from ~ 12 to ~ 0.1 Ma. The major and, partially, trace element content of these rocks roughly resemble magmas emplaced in within-plate tectonic settings. From a Sr-Nd-Pb-Hf-Os isotopic point of view, it is possible to subdivide these rocks in two subgroups. The first, defined RPV (Radiogenic Pb Volcanic) group comprises the oldest and very rare products (~ 12-4.4 Ma) occurring only in the southern sectors of Sardinia. The second group, defined UPV (Unradiogenic Pb Volcanic), comprises rocks emplaced in the remaining central and northern sectors during the ~ 4.8-0.1 Ma time range. The origin of the RPV rocks remains quite enigmatic, since they formed just a few Myr after the end of a subduction-related igneous activity but do not show any evidence of slab-derived metasomatic effects. In contrast, the complex origin of the mafic UPV rocks, characterized by low 206Pb/204Pb (17.4-18.1), low 143Nd/144Nd (0.51232-0.51264), low 176Hf/177Hf (0.28258-0.28280), mildly radiogenic 87Sr/86Sr (~ 0.7044) and radiogenic 187Os/188Os ratios (0.125-0.160) can be explained with a mantle source modified after interaction with ancient delaminated lower crustal lithologies. The strong isotopic difference between the RPV and UPV magmas and the absence of lower crustal-related features in the SR and RPV remain aspects to be solved

    Petrogenesis of a basalt-comendite-pantellerite rock suite: The Boseti Volcanic Complex (Main Ethiopian Rift)

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    Petrological and geochemical data for basic (alkali basalts and hawaiites) and silicic peralkaline rocks, plus rare intermediate products (mugearites and benmoreites) from the Pleistocene Boseti volcanic complex (Main Ethiopian Rift, East Africa) are reported in this work. The basalts are slightly alkaline or transitional, have peaks at Ba and Nb in the mantle-normalized diagrams and relatively low 87Sr/86Sr (0. 7039-0. 7044). The silicic rocks (pantellerites and comendites) are rich in sanidine and anorthoclase, with mafic phases being represented by fayalite-rich olivine, opaque oxides, aenigmatite and slightly Na-rich ferroaugite (ferrohedenbergite). These rocks were generated after prolonged fractional crystallization process (up to 90-95 %) starting from basaltic parent magmas at shallow depths and fO2 conditions near the QFM buffer. The apparent Daly Gap between mafic and evolved Boseti rocks is explained with a model involving the silicic products filling upper crustal magma chambers and erupted preferentially with respect to basic and intermediate products. Evolved liquids could have been the only magmas which filled the uppermost magma reservoirs in the crust, thus giving time to evolve towards Rb-, Zr- and Nb-rich peralkaline rhyolites in broadly closed systems. © 2009 Springer-Verlag
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