Search results for "Petrografia"
showing 10 items of 92 documents
Sulphur behaviour in Etnean magmatic system (Italy
2015
Sulfur is an essential volatile component of basaltic magmas and it is mostly dissolved as S6+ and/or S2- depending on the redox conditions. Mt. Etna continuously discharges enormous quantity of SO2 (~3563 t/d [1]). However these high flows are not fully understood in terms of S origin (magmatic or crustal) and of its behavior during magmatic evolution (fractional crystallization, magma mixing, vapor/melt fractionation [2]). Our research combines the study of sulfur in natural olivine hosted melt inclusions with an experimental study on S solubility in hydrous alkali basalts at magmatic conditions. We report new data of S in melt inclusions, belonging to six of the most characteristic Etnea…
Primo contributo sui depositi a Terra Rossa dell'Abisso del Vento, Isnello (PA).
2007
Generation of CO2-rich melts during basalt magma ascent and degassing
2013
International audience; To test mechanisms of basaltic ma gma degassing, continuous decompressions of volatile-bearing (2.7-3.8 wt% H2O, 600-1300 ppm CO2) Stromboli melts were performed from 250-200 to 50-25 MPa at 1180-1140°C. Ascent rates were varied from 0.25 to ~ 1.5 m/s. Glasses after decompression show a wide range of textures, from totally bubble-free to bubble-rich, the latter with bubble number densities from 104 to 106/cm3, similar to Stromboli pumices. Vesicularities range from 0 to ~ 20 vol%. Final melt H2O concentrations are homogeneous and always close to solubilities. In contrast, the rate of vesiculation controls the final melt CO2 concentration. High vesicularity charges ha…
PETROLOGICAL AND EXPERIMENTAL CONSTRAINTS ON THE PRE-ERUPTIVE CONDITIONS OF LA SOMMATA BASALT AND BROWN TUFFS TEPHRA (AEOLIAN ISLANDS)
2011
This work is focused on two key eruptions of Vulcano Island: 1) the most primitive magma of Vulcano erupted by the La Sommata scoria cone, a silica-undersaturated Ca-rich shoshonitic basalt with olivine-hosted primitive melt inclusions having an ultra-calcic character; 2) the most energetic eruptions of the whole Aeolian Archipelago, the Brown Tuffs (BT) eruptions, which produced several pyroclastic deposits, covering an ample age interval, spread out over a large portion of all Aeolian islands up to the northern coast of Sicily (Lucchi et al., 2008). By complementary studies of melt inclusions and experimental petrology, we pursued the following main objectives: (i) to constrain the pressu…
Seeking the mantle source and storage system of carbonatite magmas: case studies from Fuerteventura (Canary Islands) and Mt. Vulture volcano (souther…
Carbonatite magmatism is mainly associated with intraplate continental tectonic settings, with a temporal distribution from Archean to the present. The growing number of carbonatite occurrences from unconventional tectonic settings, such as oceanic contexts (e.g., Carnevale et al., 2021) or subduction zones (e.g., D’Orazio et al., 2007), received considerable attention during last two decades, given their importance as source of rare elements, and, most importantly, because they provide meaningful information about the geochemical cycle of carbon and mantle metasomatism as well. This work shows how the study of fluids trapped within minerals from carbonatites and carbonatite magmas can prov…
Melt inclusions constrain S behaviour and redox conditions in Etnean magmas
2016
Mount Etna is a complex magmatic system characterized by a continuous variability both in terms of eruptive style and composition of erupted products. Currently, its volcanic activity is marked by high gas fluxes (of above all SO2), both during eruptive and non-eruptive periods. In this study, we have studied the volatile contents and Fe speciation of olivine-hosted melt inclusions from 6 eruptions of the last 15 ky, mainly to investigate the behaviour of S during ascent and differentiation of Etnean magmas. Samples selected come from the FS eruption which is the oldest and most primitive (picritic composition, Fo91), the Mt Spagnolo and from more recent eruptions: 2002/3, 2006, 2008, and 2…
La prima serie di analisi mineralogiche sulle anfore di Ischia.
2010
Cataloghi IVA e IVB: Schede delle analisi mineralogiche.
2010
Impasti e microfoto delle sezioni sottili di alcune anfore greco italiche bollate di Ischia.
2010
Geochimica e petrografica di black shales del Livello Bonarelli, sezione di Novara di Sicilia (Monte Peloritani), Sicilicia nord-orientale: Implicazi…
2000
Black shales ad alto potenziale petrolifero, alternati ritmicamente a marne e argilliti, affiorano in associazione con Argille Varicolori (Cretaceo-Paleogene) nei pressi di Novara di Sicilia (Monti Peloritani, Sicilia nord-orientale) costituendo l’espressione sedimentaria di un evento anossico con diffusione globale (OAE2), riferibile al Cenomaniano superiore. I depositi corrispondenti a tale evento sono individuati come “Livello Bonarelli”. In detta successione, le alternanze black shales-marne-argilliti si estendono per uno spessore di circa 11 metri passando verso il basso ad alternanze irregolari di calcari marnosi, marne chiare, marne scure, argilliti e calcareniti (spessore ca. 9 m) c…