GEOCHEMISTRY OF THE GAS MANIFESTATIONS OF GREECE: METHANE AND LIGHT HYDROCARBONS

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Published: Jul 28, 2016
DOI: https://doi.org/10.12681/bgsg.11919
Keywords:
Hellenic territory hydrothermal gases cold gas emissions origin of hydrocarbon gases
K. Daskalopoulou
Università degli Studi di Palermo, Dipartimento della Terra e del Mare
W. D’Alessandro
Istituto Nazionale di Geofisica e Vulcanologia
J. Cabassi
Università degli Studi di Firenze, Dipartimento della Terra
S. Calabrese
Università degli Studi di Palermo, Dipartimento della Terra e del Mare
J. Fiebig
Goethe-Universität, Institut für Geowissenschaften
F. Grassa
Istituto Nazionale di Geofisica e Vulcanologia
K. Kyriakopoulos
National and Kapodistrian University of Athens, Department of Geology and Geoenvironment
F. Parello
Università degli Studi di Palermo, Dipartimento della Terra e del Mare
F. Tassi
Università degli Studi di Firenze, Dipartimento della Terra
Abstract

Greece has a very complex geodynamic setting deriving from a long and complicated geological history being characterized by intense seismic activity and enhanced geothermal gradient. This activity, with the contribution of an active volcanic arc, favours the existence of many gas manifestations. Depending on the prevailing gas species, the latter can be subdivided in three main groups: CO2-, N2- and CH4- dominated. In the present work, we focus on methane and light hydrocarbons (C2-C6) to define their origin. CH4 concentrations (<2 to 915,200 μmol/mol) and isotopic ratios (δ13C -79.8 to +16.9 ‰, δD -298 to +264‰) cover a wide range of values indicating different origins and/or secondary post-genetic processes. Samples from gas discharged along the Ionian coast and in northern Aegean Sea have a prevailing microbial origin. Cold and thermal gas manifestations of central and northern Greece display a prevalent thermogenic origin. Methane in gases released along the active volcanic arc is prevailingly abiogenic, although thermogenic contributions cannot be excluded. Gases collected in the geothermal areas of Sperchios basin and northern Euboea are likely affected by strong secondary oxidation processes, as suggested by their highly positive C and H isotopic values (up to +16.9‰ and +264‰ respectively) and low C1/(C2+C3) ratios.

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  • Petrology and Mineralogy
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References
Andritsos, Ν., Dalampakis, P., Karydakis, G., Kolios, Ν. and Fytikas, M., 2007. Update and
characteristics of low-enthalpy geothermal applications in Greece, Proceedings, European
Geothermal Congress EGC 2007, May 30 - June 1, 2007, Unterhaching, Germany.
D’Alessandro, W., Brusca, L., Kyriakopoulos, K., Rotolo, S., Michas, G., Minio, M. and Papadakis,
G., 2006. Diffuse and focussed carbon dioxide and methane emissions from the Sousaki
geothermal system, Greece, Geophys. Res. Lett., 33, L05307, doi: 10.1029/2006GL025777.
D’Alessandro, W., Brusca, L., Kyriakopoulos, K., Michas, G. and Papadakis, G., 2008. Methana,
the westernmost active volcanic system of the south Aegean arc (Greece): insight from fluids
geochemistry, J. Volcanol. Geotherm. Res., 178, 818-828.
D'Alessandro, W., Bellomo, S., Brusca, L., Fiebig, J., Longo, M., Martelli, M., Pecoraino, G. and
Salerno, F., 2009. Hydrothermal methane fluxes from the soil at Pantelleria Island (Italy), J.
Volcanol. Geotherm. Res., 187, 147-157.
D'Alessandro, W., Brusca, L., Martelli, M., Rizzo, A. and Kyriakopoulos, K., 2010. Geochemical
characterization of natural gas manifestations in Greece, Proceedings of the 12th
International Congress of the Geological Society of Greece, Patras, May 2010, Bulletin of
the Geological Society of Greece, 43(5), 2327–2337.
D’Alessandro, W., Bellomo, S., Brusca, L., Karakazanis, S., Kyriakopoulos, K. and Liotta, M.,
The impact on water quality of the high carbon dioxide contents of the groundwater in
the area of Florina (N. Greece). In: Lambrakis, N., Stournaras, G. and Katsanou, K., eds.,
Advances in the research of aquatic environment, Springer, Berlin, 2, 135-143.
D’Alessandro, W., Brusca, L., Kyriakopoulos, K., Bellomo, S. and Calabrese, S., 2014. A
geochemical traverse along the “Sperchios Basin - Evoikos Gulf” graben (Central Greece):
Origin and evolution of the emitted fluids, Marine and Petroleum Geology, 55, 295-308, doi:
1016/j.marpetgeo.2013.12.011.
Dimitrakopoulos, R. and Muehlenbachs, K., 1987. Biodegradation of petroleum as a source of 13C
enriched carbon dioxide in the formation of carbonate cements, Chemical Geology, 65, 283-291.
Etiope, G., Feyzullayev, A., Milkov, A.V., Waseda, A., Mizobe, K. and Sun, C.H., 2009. Evidence of
subsurface anaerobic biodegradation of hydrocarbons and potential secondary methanogenesis
in terrestrial mud volcanoes, Marine and Petroleum Geology, 26, 1692-1703.
Evans, W.C., White, L.D. and Rapp, J.B., 1998, Geochemistry of some gases in hydrothermal fluids
from the southern Juan de Fuca ridge, Journal of Geophysical Research, 15, 305-313.
Fiebig, J., Chiodini, G., Caliro, S., Rizzo, A., Spandenberg, J. and Hunziker, J.C., 2004. Chemical and
isotopic equilibrium between CO2 and CH4 in fumarolic gas discharges: generation of CH4 in
arc magmatic-hydrothermal systems, Geochimica et Cosmochimica Acta, 68, 2321-2334.
Fiebig, J., Woodland, AB., D’Alessandro, W. and Puttmann, W., 2009. Excess methane in
hydrothermal emissions is abiogenic, Geology, 37(6), 495-8.
Fytikas, M., Innocenti, F., Manetti, P., Mazzuoli, R., Peccerillo, A. and Villari, L., 1984. Tertiary to
Quarternary evolution of volcanism in the Aegean region, Geological Society of London,
Special Publications, 17, 687-699.
Fytikas, M., Innocenti, F., Kolios, N., Manetti, P. and Mazzuoli, R., 1986. The Plio- Quaternary
volcanism of the Saronikos area (western part of the active Aegean volcanic arc), Annales
Geologique des Pays Helleniques, 33, 23-45.
Fytikas, Μ., Αndritsos, Ν., Dalabakis, P. and Kolios, N., 2005. Greek Geothermal Update 2000-
, Proceedings of the World Geothermal Congress-2005, 24-29 April 2005, Antalya-
Turkey (invited paper).
Galimov, E.M., 1988. Sources and mechanisms of formation of gaseous hydrocarbons in
sedimentary rocks, Chemical Geology, 71, 77-95.
Jenden, P.D., Hilton, D.R., Kaplan, I.R. and Craig, H., 1993. Abiogenic hydrocarbons and mantle
helium in oil and gas fields. In: Howell, D.G., ed., The Future of Energy Gases: US
Geological Survey Professional Paper, 1570, 31–56.
Kyriakopoulos, K, 2010. Natural degassing of carbon dioxide and hydrogen sulphide and its
environmental impact at Milos island, Greece. In: Proceedings of 12th international congress,
Patras, May 2010, Bull Geol Soc Greece.
McCollom, T.M. and Seewald, J.S., 2007. Abiotic synthesis of organic compounds in deep sea
hydrothermal environments, Chemical Reviews, 107, 382-401.
Mitropoulos, P., Tarney, J., Saunders, D. and Marsh, N., 1987. Petrogenesis of Cenozoic volcanic
rocks from the Aegean Island Arc, Journ. Volcanology and Geothermal Research, 32, 177-193.
Pallasser, R.J., 2000. Recognising biodegradation in gas/oil accumulations through the δ13C
compositions of gas components, Organic Geochemistry, 31, 1363-1373.
Pe-Piper, G. and Piper, D.J.W., 2006. Unique features of the Cenozoic igneous rocks of Greece. In:
Dilek, Y. and Pavlides, S., eds., Postcollisional tectonics and magmatism in the
Mediterranean region and Asia, Geological Society of America, Special Paper, 409, 259-282.
Prinzhofer, A.A. and Battani, A., 2003. Gas isotopes tracing: an important tool for hydrocarbon
exploration, Oil and Gas Science and Technology, 58(2), 229-311.
Sano, Y. and Marty, B., 1995. Origin of carbon in fumarolic gas from island arcs, Chemical Geology,
, 265-274.
Sano, Y. and Wakita, H., 1985. Geographical distribution of 3He/4He in Japan: implications for arc
tectonics and incipient magmatism, Journal of Geophysical Research, 90, 8729-8741.
Schoell, M., 1980. The hydrogen and carbon isotopic composition of methane from natural gases of
various origins, Geochimica et Cosmochimica Acta, 44, 649-661.
Schoell, M., 1988. Multiple origins of methane in the Earth, Chemical Geology, 71, 1-10.
Tassi, F., Fiebig, J., Vaselli, O. and Nocentini, M., 2012. Origins of methane discharging from
volcanic-hydrothermal, geothermal and cold emissions in Italy, Chem. Geol., 310-311, 36-
http://dx.doi.org/10.1016/j.chemgeo.2012.03.018.
Tassi, F., Bonini, M., Montegrossi, G., Capecchiacci, F., Capaccioni, B. and Vaselli, O., 2012.
Origin of light hydrocarbons in gases from mud volcanoes and CH4-rich emissions, Chem.
Geol., 294-295, 113-126.
van Hinsbergen, D.J.J., Langereis, C.G. and Meulenkamp, J.E., 2005. Revision of the timing,
magnitude and distribution of Neogene rotations in the western Aegean region,
Tectonophysics, 396, 1-34, doi: 10.1016/j.tecto.2004.10.001.
Vaselli, O., Tassi, F., Montegrossi, G., Capaccioni, B. and Giannini, L., 2006. Sampling and analysis
of volcanic gases, Acta Volcanol., 18, 65-76.
Whiticar, M.J., Faber, E. and Schoell, M., 1986. Biogenic methane formation in marine and
freshwater environments: CO2 reduction vs. acetate fermentation - isotopic evidence,
Geochimica et Cosmochimica Acta, 50, 693-709.
Whiticar, M.J. and Suess, E., 1990. Hydrothermal hydrocarbon gases in the sediments of the King-
George Basin, Bransfield Strait, Antarctica, Applied Geochemistry, 5, 135-147.
Whiticar, M.J., 1999. Carbon and hydrogen isotope systematics of bacterial formation and oxidation
of methane, Chemical Geology, 161, 291-314.
Welhan, J.A., 1988. Origins of methane in hydrothermal systems, Chemical Geology, 71, 183-198.
Zhang, J., Quay, P.D. and Wilbur, D.O., 1995. Carbon isotope fractionation during gas-water
exchange and dissolution of CO2, Geochimica et Cosmochimica Acta, 59, 107-114.
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