SOIL CO2 DIFFUSE DEGASSING AT CHACHIMBIRO VOLCANO, ECUADOR

Diffuse CO2 soil degassing is often a prominent feature of geothermal systems related to the presence of magma in volcanic regions. Studies have shown that identifying the spatial distribution of these emissions can improve our understanding of the systems and lead us to recognize up-flow paths and, ultimately, quantifying the thermal energy being released. This study presents the first CO2 diffuse degassing analysis ever carried out at Chachimbiro volcano, situated at the north of Ecuador’s Andean Cordillera; the location of the most advanced geothermal project in the country. The purpose of this investigation is to better understand the distribution of heat and permeability to identify future targets for geothermal exploration/exploitation. The survey covered an area of 3.6 km2 with 642 points measured and 20 samples collected for carbon isotopic analysis. Isotopic results show two CO2 sources contributing to the system: biogenic and magmatic; which correlate with two distinct CO2 flux populations estimated by a graphical statistical approach. This research applies Indicator Kriging using R programming language which is able to manage highly variable phenomena without cutting high values or nonlinear transformation to estimate diffuse degassing structures of anomalous (magmatic-derived) CO2 flux. We conclude that there are several areas of high flux that may endorse the geothermal conceptual model of Chachimbiro geothermal system that pinpoint good targets for future exploration drilling programs