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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS001 Oral Presentation 1723
The role of mechanochemical production for the CO2 released from the
seismic area of Apennine Chain
Dr. Francesco Italiano
Sezione di Palermo INGV IAVCEI
Giovanni Martinelli, Sonia Pizzullo, Paolo Plescia
The evidence that a large amount of carbon dioxide is released through wide areas in the absence of
clear contribution from the mantle or from mantle-derived fluids leads to the hypothesis that an
additional energy source has to be considered to justify the origin of the released CO2. The CO2-
dominated gases released along the Thyrrhenian sector of the Apennine chain come from both
geothermal and seismic areas: they are mainly marked by 3He/4He ratios of radiogenic signature, but
some cases (i.e Larderello geothermal area) where a mantle signature is evident. Experimental results
clearly confirm the possibility of producing CO2 by grinding carbonate rocks as an effect of the total
dissociation of calcite. Laboratory experiments carried out by a ring mill demonstrate that stress
application on calcite and calcite/clay mixture produces CO2 and CH4 and, even though the
experimental approach cannot be compared to a natural system, it shows a way to model the processes
occurring on fault planes where mineralogical phases are involved and modified with the total
reorganization of the crystalline lattice and the contemporary production of a gas phase. The evidence
that the mechanochemical production of CO2 and CH4 plays an important role over the entire Apennine
chain leads to the consideration that similar greenhouse gas production has to be evaluated on a global
scale.
Keywords: co2 production, mechanochemical, seismic areas