Location, flow–rate, extension of the hydrogeological basin, chemical and isotopic analyses of the 160 springs considered in this study, along with the results of the carbon mass balance. <i>Measuring and interpreting CO<sub>2</sub> fluxes at regional scale: the case of Apennines, Italy</i>
2018-09-19T07:50:42Z (GMT) by
Tectonically active regions are often characterized by a large amounts of carbon dioxide degassing, and estimation of the total CO<sub>2</sub> discharged to the atmosphere from tectonic structures, hydrothermal systems and inactive volcanic areas is crucial for the definition of present-day global Earth degassing. The carbon balance of regional aquifers is a powerful tool to quantify the diffuse degassing of deep inorganic carbon sources because the method integrates the CO<sub>2</sub> flux over large areas. Its application to peninsular Italy shows that the region is characterized by specific CO<sub>2</sub> fluxes higher than the baseline determined for the geothermal regions of the world, and that the amount of endogenous CO<sub>2</sub> discharged through diffuse regional degassing (~2.1×1011 mol yr<sup>-1</sup>) is the major component of the geological CO<sub>2</sub> budget of Italy, definitely prevailing over the CO<sub>2</sub> discharged by Italian active volcanoes and volcanoes in hydrothermal activity. Furthermore, the positive correlation between geothermal heat and deep CO<sub>2</sub> dissolved in the groundwater of central Italy suggests that (i) the geothermal heat is transported into the aquifers by the same hot CO<sub>2</sub> rich fluids causing the Italian CO<sub>2</sub> anomaly and (ii) the advective heat flow is the dominant form of heat transfer of the region.