Temporal and spatial variations of CO2 diffuse volcanic degassing on Cuicocha Caldera Lake – Ecuador

Geochemistry of Water and Gas Emissions From Cuicocha and Quilotoa Volcanic Lakes, Ecuador

“…Both are located along the Otavalo-Umpalá fracture zone (Hanus, 1987). However, above the older units of the Cotacachi volcano four principal parasitic domes were emplaced, of which Cuicocha is the youngest (Sierra et al, 2021). Its collapse formed the caldera approximately 4,500 years ago, which has since been the location of intense eruptions with volcanic explosivity indexes (VEI) of 5-6, lahars, and massive pyroclastic flows through to approximately 1,300 years ago (Hillebrant, 1989).…”

“…The study of the physical and chemical characteristics of these water masses constitutes a powerful tool to evaluate the activity level of volcanic systems (Mazot and Taran, 2009;Rouwet et al, 2014Rouwet et al, , 2015Andrade et al, 2016Andrade et al, , 2019Andrade et al, , 2021Hernández et al, 2017). After the two well-known limnic eruptions ocurred in Camerron at Lake Monoun in 1984 and Lake Nyos in 1986, special importance has been paid to the development of CO 2 emission surveys in different volcanic lakes (Padrón et al, 2008;Mazot and Taran, 2009;Hernández et al, 2011Hernández et al, , 2017Pérez et al, 2011;Mazot et al, 2014;Melián et al, 2017;Sierra et al, 2021). These periodic CO 2 emission surveys in volcanic lakes are an important task for the surveillance of these systems.…”

“…These periodic CO 2 emission surveys in volcanic lakes are an important task for the surveillance of these systems. Although much effort has been made in the last 15 years to study the diffuse CO 2 emission rate at several volcanic lakes in the world (Mazot and Taran, 2009;Pérez et al, 2011;Melián et al, 2017), many lakes are still noninvestigated and very few have been regularly monitored to create time series (Sierra et al, 2021).…”

“…The authors estimated the CO 2 emission of the lake at 53 t d −1 using the sequential Gaussian simulation (sGs) method. More recently, Sierra et al (2021) presented the results of long-term analysis of diffuse CO 2 emission, estimating an emission of 400 kt of CO 2 during the period 2011-2019 (8.13 years), with an average rate of ∼135 t d −1 . Sierra et al (2021) considered that the CO 2 emission peak registered in 2012-2013 was related to the anomalous seismicity occurred during this period due to deep origin processes that affect the hydrothermal system.…”

Geochronological evolution of the potentially active Iliniza Volcano (Ecuador) based on new K-Ar ages

“…The formation of lava dome complexes is also recurrent, and often appears during the final eruptive stages following the transition from high-silica andesites to dacites (e.g., Hidalgo, 2006;Robin et al, 2010;Almeida et al, 2019;Bellver-Baca et al, 2020). Moreover, these stages also involve highly explosive eruptions (e.g., Hidalgo et al, 2008;Robin et al, 2008;Andrade et al, 2021), directed blast events (e.g., Bernard et al, 2014), and the formation of two 3 km-wide calderas (i.e., Cuicocha and Quilotoa calderas;von Hillebrandt, 1989;Mothes and Hall, 2008;Sierra et al, 2020). Notably, large explosive eruptions occurred during the Holocene in the northern and central segments of the Volcanic Front (Fig.…”