Estimation of the geothermal potential of the Caldara di Manziana site in the Sabatini Volcanic District (central Italy) by integrating geochemical data and 3D-GIS modelling

• High medium-enthalpy geothermal reservoir of central Italy are in carbonate rock.
• The Caldara of Manziana is characterized by a very high soil and advective CO2 flux.
• Gas is dominated by CO2 and its composition has been used for T-P estimations.
• The TINs model allowed to estimate depth and temperature of the top of the geothermal reservoir.
• The data obtained in this study allowed, an estimation of CM geothermal potential.

This study evaluated the geothermal potential of Caldara di Manziana in central Italy. The chemical composition of gas emissions was used for geothermometric-geobarometric estimations and the total amount of CO2 released was assessed. The subsurface geology was reconstructed using data from deep exploratory and shallow temperature-gradient wells. The bottom of the superficial volcanic deposits, the thickness of the impervious flysch cover and the top of the geothermal reservoir hosted in fractured Mesozoic limestones were reconstructed by a 3D-GIS modelling. Our results are consistent with a geothermal reservoir (T ∼140 °C) at ∼1000 m depth, with an estimated thermal energy capacity of 46–48 MWt.