Options
Geochemistry of the submarine gaseous emissions of Panarea (Aeolian Islands, Southern Italy): magmatic vs. hydrothermal origin and implications for volcanic surveillance
Author(s)
Language
English
Status
Published
Peer review journal
Yes
Title of the book
Issue/vol(year)
4/163 (2006)
Publisher
Birkhauser Verlag
Issued date
2006
Alternative Location
Keywords
Abstract
Abstract—The marine sector surrounding Panarea Island (Aeolian Islands, South Italy) is affected by
widespread submarine emissions of CO2 -rich gases and thermal water discharges which have been known
since the Roman Age. On November 3rd, 2002 an anomalous degassing event affected the area, probably in
response to a submarine explosion. The concentrations of minor reactive gases (CO, CH4 and H2) of
samples collected in November and December, 2002 show drastic compositional changes when compared
to previous samples collected from the same area in the 1980s. In particular the samples collected after the
November 3rd phenomenon display relative increases in H2 and CO and a strong decrease in the CH4
contents, while other gas species show no significant change. The interaction of the original gas with
seawater explains the variable contents of CO2, H2S, N2, Ar and He which characterize the different
samples, but cannot explain the large variations of CO, CH4 and H2 which are instead compatible with
changes in the redox, temperature and pressure conditions of the system. Two models, both implying an
increasing input of magmatic fluids are compatible with the observed variations of minor reactive species.
In the first one, the input of magmatic fluids drives the hydrothermal system towards atypical (more
oxidizing) redox conditions, slowly pressurizing the system up to a critical state. In the second one, the
hydrothermal system is flashed by the rising high-T volcanic fluid, suddenly released by a magmatic body
at depth. The two models have different implications for volcanic surveillance and risk assessment: In the
first case, the November 3rd event may represent both the culmination of a relatively slow process which
caused the overpressurization of the hydrothermal system and the beginning of a new phase of quiescence.
The possible evolution of the second model is unforeseeable because it is mainly related to the thermal,
baric and compositional state of the deep magmatic system that is poorly known.
widespread submarine emissions of CO2 -rich gases and thermal water discharges which have been known
since the Roman Age. On November 3rd, 2002 an anomalous degassing event affected the area, probably in
response to a submarine explosion. The concentrations of minor reactive gases (CO, CH4 and H2) of
samples collected in November and December, 2002 show drastic compositional changes when compared
to previous samples collected from the same area in the 1980s. In particular the samples collected after the
November 3rd phenomenon display relative increases in H2 and CO and a strong decrease in the CH4
contents, while other gas species show no significant change. The interaction of the original gas with
seawater explains the variable contents of CO2, H2S, N2, Ar and He which characterize the different
samples, but cannot explain the large variations of CO, CH4 and H2 which are instead compatible with
changes in the redox, temperature and pressure conditions of the system. Two models, both implying an
increasing input of magmatic fluids are compatible with the observed variations of minor reactive species.
In the first one, the input of magmatic fluids drives the hydrothermal system towards atypical (more
oxidizing) redox conditions, slowly pressurizing the system up to a critical state. In the second one, the
hydrothermal system is flashed by the rising high-T volcanic fluid, suddenly released by a magmatic body
at depth. The two models have different implications for volcanic surveillance and risk assessment: In the
first case, the November 3rd event may represent both the culmination of a relatively slow process which
caused the overpressurization of the hydrothermal system and the beginning of a new phase of quiescence.
The possible evolution of the second model is unforeseeable because it is mainly related to the thermal,
baric and compositional state of the deep magmatic system that is poorly known.
References
CALANCHI, N., CAPACCIONI, B., MARTINI, M., TASSI, F., and VALENTINI, L. (1995), Submarine gasemission
from Panarea Island (Aeolian Archipelago); distribution of inorganic and organic compounds and
inferences about source conditions, Acta Vulcanologica 7, 43–48.
CALANCHI, N., PECCERILLO, A., TRANNE, C.A., LUCCHINI, F., ROSSI, P.L., KEMPTON, P., and BARBIERI,
M., (2002), Petrology and geochemistry of volcanic rocks from the Island of Panarea: Implications for
mantle evolution beneath the Aeolian Island arc (southern Tyrrhenian Sea), J. Volcanol. Geotherm. Res.
115, 367–395.
CHIODINI, G. (1994), Temperature, pressure and redox conditions governing the composition of the cold CO2
gases discharged in north Latium (Central Italy), Appl. Geochem. 9, 287–295.
CHIODINI, G. and CIONI, R. (1989), Gas geobarometry for hydrothermal systems and its application to some
Italian geothermal areas, Appl. Geochem. 4, 465–472.
CHIODINI, G. and MARINI, L. (1998), Hydrothermal gas equilibria: The H2O-H2-CO2-CO-CH4 system,
Geochim. Cosmochim. Acta. 62, 2673–2687.
CHIODINI, G., CIONI, R., andMARINI, L. (1993), Reactions governing the chemistry of crater fumaroles from
Vulcano Island, Italy, and implications for volcanic surveillance, Appl. Geochem. 8, 357–371.
CHIODINI, G., D’ALESSANDRO, W., and PARELLO, F. (1996), Geochemistry of gases and waters discharged
by the mud volcanoes at Paterno`, Mt Etna (Italy), Bull. Volcanol. 58, 51–58.
CHIODINI, G., MARINI, L., and RUSSO, M. (2001), Geochemical evidence for the existence of hightemperature
brines at Vesuvio volcano, Italy, Geochem. Cosm. Acta 65, 2129–2147.
D’AMORE, F. and PANICHI, C. (1980), Evaluation of deep temperature of hydrothermal systems by a new gasgeothermometer,
Geochim. Cosmochim. Acta. 44, 549–556.
DE ASTIS, G., PECCERILLO, A., KEMPTON, P.D., LA VOLPE, L., and WU TSAI, W. (2000), Transition from
calc-alkaline to potassium-rich magmatism in subduction environments: Geochemical and Sr, Nd, Pb
isotopic constraints from the island of Vulcano (Aeolian arc), Contrib. Mineral. Petrol. 139, 684–703.
ELLAM, R.M.,HAWKESWORTH, C.J.,MENZIES,M.A., and ROGERS,N.W. (1989), The volcanism of Southern Italy:
Role of subduction and relationship between potassic and sodic alkalinemagmatism, J.Geophys.Res. 94, 4589–4601.
FALSAPERLA, S. and SPAMPINATO, S. (1999), Tectonic seismicity at Stromboli volcano (Italy) from historical
data and seismic records, Earth Planet. Sci. Lett. 173, 425–437.
GABBIANELLI, G., GILLOT, G.Y., LANZAFAME, G., ROMAGNOLI, C., and ROSSI, P.L. (1990), Tectonic and
volcanic evolution of Panarea (Aeolian Islands, Italy), Marine Geology 92, 313–326.
GAMBERI, F., MARANI, M., and SAVELLI, C. (1997), Tectonic, volcanic and hydrothermal features of a
submarine portion of the Aeolian arc (Tyrrhenian Sea), Marine Geology 140, 167–181.
GIGGENBACH, W.F. (1975), A simple method for the collection and analysis of volcanic gas samples, Bull.
Volcanol. 39, 132–145.
GIGGENBACH, W.F. (1980), Geothermal gas equilibria, Geochim. Cosmochim, Acta 44, 2021–2032.
GIGGENBACH, W.F. (1987), Redox processes governing the chemistry of fumarolic gas discharges from White
Island, New Zeland, Appl. Geochem. 2, 143–161.
GIGGENBACH, W.F., Chemical composition of volcanic gases. In Monitoring and Mitigation of Volcano
Hazards (R. Scarpa, R.I. Tilling, eds.) (Springer, Berlin 1996) pp. 221–256
INGV CATANIA (2002), Attivita` scientifiche multidisciplinari iniziate e in corso nell’area di Panarea, Internal
report, 21 November 2002, Catania.
ITALIANO, F. and NUCCIO, P.M. (1991), Geochemichal investigations of submarine exhalations to the east of
Panarea, Aeolian Islands, Italy, J. Volcanol. Geotherm. Res. 46, 125–141.
KNIGHT, C.L. and BODNAR, R.J. (1989). Synthetic fluid inclusions: IX. Critical properties of NaCl-H2O
solutions, Geochim. Cosmochim. Acta 53, 3–8.
NERI, G., BARBERI, G., ORECCHIO, B., and ALOISI, M. (2002), Seismotomography of the crust in the
transition zone between the southern Tyrrhenian and Sicilian tectonic domains, Geophys. Res. Lett. 29,23
doi:10.1029/2002GL015562.
WANG, C.Y., HWANG, W .T., and SHI, Y. (1989), Thermal evolution of a rift basin: The Tyrrhenian Sea,
J. Geophys. Res. 94, 3991–4006.
from Panarea Island (Aeolian Archipelago); distribution of inorganic and organic compounds and
inferences about source conditions, Acta Vulcanologica 7, 43–48.
CALANCHI, N., PECCERILLO, A., TRANNE, C.A., LUCCHINI, F., ROSSI, P.L., KEMPTON, P., and BARBIERI,
M., (2002), Petrology and geochemistry of volcanic rocks from the Island of Panarea: Implications for
mantle evolution beneath the Aeolian Island arc (southern Tyrrhenian Sea), J. Volcanol. Geotherm. Res.
115, 367–395.
CHIODINI, G. (1994), Temperature, pressure and redox conditions governing the composition of the cold CO2
gases discharged in north Latium (Central Italy), Appl. Geochem. 9, 287–295.
CHIODINI, G. and CIONI, R. (1989), Gas geobarometry for hydrothermal systems and its application to some
Italian geothermal areas, Appl. Geochem. 4, 465–472.
CHIODINI, G. and MARINI, L. (1998), Hydrothermal gas equilibria: The H2O-H2-CO2-CO-CH4 system,
Geochim. Cosmochim. Acta. 62, 2673–2687.
CHIODINI, G., CIONI, R., andMARINI, L. (1993), Reactions governing the chemistry of crater fumaroles from
Vulcano Island, Italy, and implications for volcanic surveillance, Appl. Geochem. 8, 357–371.
CHIODINI, G., D’ALESSANDRO, W., and PARELLO, F. (1996), Geochemistry of gases and waters discharged
by the mud volcanoes at Paterno`, Mt Etna (Italy), Bull. Volcanol. 58, 51–58.
CHIODINI, G., MARINI, L., and RUSSO, M. (2001), Geochemical evidence for the existence of hightemperature
brines at Vesuvio volcano, Italy, Geochem. Cosm. Acta 65, 2129–2147.
D’AMORE, F. and PANICHI, C. (1980), Evaluation of deep temperature of hydrothermal systems by a new gasgeothermometer,
Geochim. Cosmochim. Acta. 44, 549–556.
DE ASTIS, G., PECCERILLO, A., KEMPTON, P.D., LA VOLPE, L., and WU TSAI, W. (2000), Transition from
calc-alkaline to potassium-rich magmatism in subduction environments: Geochemical and Sr, Nd, Pb
isotopic constraints from the island of Vulcano (Aeolian arc), Contrib. Mineral. Petrol. 139, 684–703.
ELLAM, R.M.,HAWKESWORTH, C.J.,MENZIES,M.A., and ROGERS,N.W. (1989), The volcanism of Southern Italy:
Role of subduction and relationship between potassic and sodic alkalinemagmatism, J.Geophys.Res. 94, 4589–4601.
FALSAPERLA, S. and SPAMPINATO, S. (1999), Tectonic seismicity at Stromboli volcano (Italy) from historical
data and seismic records, Earth Planet. Sci. Lett. 173, 425–437.
GABBIANELLI, G., GILLOT, G.Y., LANZAFAME, G., ROMAGNOLI, C., and ROSSI, P.L. (1990), Tectonic and
volcanic evolution of Panarea (Aeolian Islands, Italy), Marine Geology 92, 313–326.
GAMBERI, F., MARANI, M., and SAVELLI, C. (1997), Tectonic, volcanic and hydrothermal features of a
submarine portion of the Aeolian arc (Tyrrhenian Sea), Marine Geology 140, 167–181.
GIGGENBACH, W.F. (1975), A simple method for the collection and analysis of volcanic gas samples, Bull.
Volcanol. 39, 132–145.
GIGGENBACH, W.F. (1980), Geothermal gas equilibria, Geochim. Cosmochim, Acta 44, 2021–2032.
GIGGENBACH, W.F. (1987), Redox processes governing the chemistry of fumarolic gas discharges from White
Island, New Zeland, Appl. Geochem. 2, 143–161.
GIGGENBACH, W.F., Chemical composition of volcanic gases. In Monitoring and Mitigation of Volcano
Hazards (R. Scarpa, R.I. Tilling, eds.) (Springer, Berlin 1996) pp. 221–256
INGV CATANIA (2002), Attivita` scientifiche multidisciplinari iniziate e in corso nell’area di Panarea, Internal
report, 21 November 2002, Catania.
ITALIANO, F. and NUCCIO, P.M. (1991), Geochemichal investigations of submarine exhalations to the east of
Panarea, Aeolian Islands, Italy, J. Volcanol. Geotherm. Res. 46, 125–141.
KNIGHT, C.L. and BODNAR, R.J. (1989). Synthetic fluid inclusions: IX. Critical properties of NaCl-H2O
solutions, Geochim. Cosmochim. Acta 53, 3–8.
NERI, G., BARBERI, G., ORECCHIO, B., and ALOISI, M. (2002), Seismotomography of the crust in the
transition zone between the southern Tyrrhenian and Sicilian tectonic domains, Geophys. Res. Lett. 29,23
doi:10.1029/2002GL015562.
WANG, C.Y., HWANG, W .T., and SHI, Y. (1989), Thermal evolution of a rift basin: The Tyrrhenian Sea,
J. Geophys. Res. 94, 3991–4006.
Type
article
File(s)
No Thumbnail Available
Name
246.pdf
Size
424.9 KB
Format
Adobe PDF
Checksum (MD5)
9e162450f98080246db6902a8de34d42