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Etna volcano : geochemistry and budget of volatiles. Implications for the magma feeding system, the structure of the edifice, and the eruptive activity

Objective

The purpose of this work programme is to carry out a
comprehensive and multidisciplinary study of the sources,
chemistry, behaviour and fluxes of volcanic/magmatic volatiles at
Etna, in order to contribute to better understanding of the magma
feeding system and the eruptive dynamics of this volcano.


Volatiles are studied in the both gas phases and the solid
phases. For gas phases the following analyses are carried out in
this project: airborne gas flux measurements and plume sampling,
analysis of radioactive and stable trace-metals in Etna's plume,
infra-red remote analysis of plume gases, and improvement of Etna
monitoring by UV correlation spectrometry (COSPEC).

These experimental approaches are utilized to provide information
about crater plume emissions. In order to quantify the whole
energy and volatile output from the volcano, and its temporal
variations, fumarolic and soil gas emissions are studied, with
complementary actions: prospections, sampling for chemical and
isotopic analysis, airborne mapping, automatic continuous
monitoring of CO2, Rn, H2, as well as meteorological
hydrodynamic parameters.

Various sophisticated analytical technics will be also used for
chemical and mineralogical analysis of fumarolic sublimates:
polarized microscopy, X-ray fluorescence, atomic absorption,
scanning emission spectroscopy, ion probe, secondary ion mass
spectrometry. Data reduction and analysis will be done with
available computing equipments.

Concerning volatiles in lava, the following analyses will be
carried out: geochemistry of trace-elements and major volatiles
(H,S,Cl,F) in melt inclusions and matrix glasses (neutron
activation, nuclear (PIXE), electron and ionic microprobes, mass
spectrometry), abundances and isotopic composition of rare gases,
carbon and oxygen, and vesicularity and volatile control on the
modal composition of Etna lavas.

The results of this project are expected to be: Quantitative
assessment of chemistry and total output of volatile emissions
from Etna: crater plume, fumaroles and sublimates, soil
emanations, gaseous springs (major, minor and trace elements;
stable and radioactive isotopic species). Identification and
survey of their temporal variations with volcanic activity or/and
geophysical events; characterization of their spatial
relationships with the main structures of the edifice and the
hydrological system. Chemical and isotopic characterization of
volatiles in the magma source, of their fractionation during
magma ascent, differentiation and degassing, and evaluation of
possible interactions with the local crustal basement.
Quantification of the volume, residence time and degassing mode
of intrusive magma batches. Improvement of the geochemical
monitoring of Etna.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Centre National de la Recherche Scientifique (CNRS)
Address
Avenue De La Terrasse
91198 Gif-sur-yvette
France

Participants (9)

Bureau de Recherches Géologiques et Minières (BRGM)
France
Address
Avenue De Concyr
45060 Orléans
Consiglio Nazionale delle Ricerche (CNR)
Italy
Address
Piazza Roma 2
95123 Catania
Consiglio Nazionale delle Ricerche (CNR)
Italy
Address
Via Archirafi 36
90123 Palermo
INSTITUT DE PHYSIQUE DU GLOBE DE PARIS
France
Address
Place Jussieu 4, Tour 14-24, 2Eme Etage
Paris
Open University
United Kingdom
Address
Walton Hall
MK7 6AA Milton Keynes
THE UNIVERSITY OF MILANO
Italy
Address
Via Golgi 19
20133 Milano
Università degli Studi di Bari
Italy
Address
Via Orabona 4
70124 Bari
Università degli Studi di Palermo
Italy
Address
Via Archirafi
90123 Palermo
Università degli Studi di Pisa
Italy
Address
Via Santa Maria Degli Scalzi 53
56126 Pisa