Carbon dioxide degassing from the Albani Hills volcanic region, Central Italy

• Published in: Chemical geology Vol. 177; no. 1; pp. 67 - 83
• Main Authors: Chiodini, G, Frondini, F
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-07-2001
• Subjects: Albani Hills; Carbon dioxide; Gas emissions; Gas hazard; Groundwater; Italy, Albani Hills; Italy; Albani Hills; Gas hazard; Groundwater; Carbon dioxide; Gas emissions
• ISSN: 0009-2541; 1872-6836
• DOI: 10.1016/S0009-2541(00)00382-X

The Albani Hills are affected by strong CO
2 degassing processes. The amount of CO
2, which rises from the depths and subsequently dissolves into shallow groundwater, has been estimated to be more than 4.2×10
9 mol year
−1. Most of the gas is released in localised anomalous spots (Lavinio, Solforata, and Ciampino–Albano–Nemi areas), generated by fluid leakage processes from buried pressurized reservoirs hosted by structural highs of the calcareous–siliceous marly basement. The groundwater circulating in the anomalous areas becomes CO
2 oversaturated, generating observable gas manifestations whose composition is mainly controlled by gas–liquid separation processes. A gas flow rate of 6.1×10
8 mol year
−1 has been measured from the two larger manifestations using the accumulation chamber technique. The presence at shallow level of CO
2 oversaturated groundwater can explain several episodes of sudden release of gas which was documented by historical chronicles from Roman times, until now.