The Carbon Dioxide Emission as Indicator of the Geothermal Heat Flow: Review of Local and Regional Applications with a Special Focus on Italy

We review the methods based on the measurement of CO2 emissions for the computation
of geothermal heat flow, both at a local (hydrothermal sites, a few km2) and regional scale (hundreds
km2). At the local scale, we present and discuss the cases of the Latera caldera and Torre Alfina
(Italy) geothermal systems. At Torre Alfina and Latera, the convection process sustains a CO2
emission of ~1 kg s–1 and ~4 kg s–1, and heat flows of 46 MW and 130 MW, respectively. At the
regional scale, we discuss the case of the central Apennine (Italy), where CO2 mass and enthalpy
balances of regional aquifers highlights a wide and strong thermal anomaly in an area of low
conductive heat flow. Notably, the CO2/heat ratios computed for the central Apennines are very
similar to those of the nearby geothermal systems of Latium and Tuscany, suggesting a common
source of CO2‐rich fluids ascribed to the Tyrrhenian mantle.

PRIN2017‐2017LMNLAW “Connect4Carbon”

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