Extracting geothermal potential areas in Ecuador using hydrogeochemical data and their principal component analysis

Abstract

This study advances geothermal exploration in Ecuador through the application of Principal Component Analysis (PCA) to both existing geochemical data from the literature and new samples collected from previously little or unstudied springs, such as El Hondón, Salvefaccha, Quilotoa, Salinas de Bolívar, and Santa Rosa de Mamanguy. Ecuador's geothermal potential is significant, with six major geothermal plays covering 49.2% of the national territory, particularly in the northern and southern Andes, and parts of the southwestern coast.
A dataset comprising 451 samples was analyzed, including temperature, pH, and major ions, allowing for a comprehensive characterization of the geothermal waters. Geochemical classification using ternary diagrams was employed to assess the geochemical behavior, followed by the application of PCA to identify key factors influencing geothermal potential. Reservoir temperatures were estimated in the range of 68 to 155 °C for Quilotoa, 66 to 171 °C for El Hondón, 75 to 233 °C for Salvefaccha, and 62 to 231 °C for Oyacachi using alkali geothermometers. These estimated temperatures highlight the suitability of these sites for future geothermal exploration, both for electricity generation and direct-use applications.
PCA results revealed that conservative ions (Cl?, Na?, K?) and temperature are key factors in the variability of geothermal waters, and identified several sites, including Portovelo, Nangulví, and Chimborazo among others, in the high-interest quadrant of the biplot, suggesting the existence of high-temperature hydrothermal systems. These findings highlight promising areas for future geothermal exploration and development.