Buono, Gianmarco (2019) Degassing of alkaline magmas in volcanic conduit during explosive eruptions. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Degassing of alkaline magmas in volcanic conduit during explosive eruptions
Buono, Gianmarcogianmarco.buono@unina.it
Date: 10 December 2019
Number of Pages: 163
Institution: Università degli Studi di Napoli Federico II
Department: Scienze della Terra, dell'Ambiente e delle Risorse
Dottorato: Scienze della Terra, dell'ambiente e delle risorse
Ciclo di dottorato: 32
Coordinatore del Corso di dottorato:
Fedi, Mauriziomaurizio.fedi@unina.it
Petrosino, PaolaUNSPECIFIED
Pappalardo, LuciaUNSPECIFIED
Date: 10 December 2019
Number of Pages: 163
Uncontrolled Keywords: volcanology; igneous petrology; magma degassing
Settori scientifico-disciplinari del MIUR: Area 04 - Scienze della terra > GEO/07 - Petrologia e petrografia
Area 04 - Scienze della terra > GEO/08 - Geochimica e vulcanologia
Date Deposited: 17 Dec 2019 16:22
Last Modified: 17 Nov 2021 12:08
URI: http://www.fedoa.unina.it/id/eprint/12969


Degassing of magma strongly controls its transfer into the Earth’s crust from reservoirs towards the surface and, in case of eruption, the eruptive style, which in turn drives tephra transport and emplacement as well as atmospheric impact. Understanding how degassing works is particularly challenging in the case of poorly explored alkaline magmas. In fact, they frequently fed powerful eruptions, although their low viscosity is generally more typical of magmas related to less explosive or effusive eruptions. In this work, degassing mechanisms and timescales of alkaline melts have been investigated combining petrological characterization of natural volcanic rocks emitted during eruptions with different volcanic explosivity index (VEI) from the Neapolitan alkaline volcanism (including Campi Flegrei caldera and Somma-Vesuvius), HT-HP (high temperature and pressure) decompression experiments, numerical modeling of magma vesiculation and reviewed literature data. In particular, 3D microtextural explorations on natural and experimental samples have been performed using X-ray computed microtomography, an imaging technique only recently introduced in Earth science applications. The obtained results have allowed (i) the definition of a new protocol of 3D imaging textural characterization based on automatic algorithms aimed at correctly examining rocks with highly interconnected pore networks, which are difficult to quantitatively investigate using the procedures employed so far in volcanology; (ii) furnishing of conceptual models and constraints useful to better improve knowledge on degassing of alkaline magmas during different eruptive scenarios and ascent conditions as well as interpret surface-monitored signals associated with explosive eruptions; (iii) the exploration of the influence of external environmental factors (e.g. interactions between magma and wall-rocks or external water) on magma degassing, particularly focusing on the effects of the rapid release of external carbon dioxide on the increment of eruption explosivity in volcanic systems located in carbonate bedrocks.


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