This project is inserted in the DECADE initiative of the DCO and intends to improve the knowledge about CO2
volcanic emissions in Terceira Island, where very little is known about the secondary manifestations of volcanism. The only fumarolic field found in the island is located in the central part of the island, where the NW-SE periodically active basaltic fissure zone intersects the dormant volcanic structure of Pico Alto. Integration of gas geochemical (soil degassing, fumarolic fields), structural, and petrological data (fluid inclusions) will contribute not only to estimate the CO2
released in this volcanic area, but also to understand the origin of the volatiles trying to follow the path from depth until surface. To accomplish these objectives, we will carry out extensive field surveys at Terceira Island to sample gas released from soils and from the fumarolic emissions, as well as collect adequate rock samples to perform fluid inclusions studies. At the same time as the soil CO2
flux measurements, we will collect gas samples to measure carbon isotopic compositions based on the accumulation chamber method. In addition, modeling of the soil CO2
flux variations in the permanent CO2
flux station installed at Furnas do Enxofre fumarolic field will contribute to identifying external factors (e.g., meteorological) that may interfere with the CO2
emission, as well as recognize daily and seasonal variations which were already observed in other degassing areas of the Azores archipelago. Terceira Island may thus be used as a test site to integrate different methodologies that can be extrapolated to other degassing areas.