Comment on Estimating the depth and evolution of intrusions at resurgent calderas: Los Humeros (Mexico) by Urbani et al. (2020)

Abstract. A multiple magmatic intrusions model has been proposed by Urbani et al. (2020) for the resurgence of the Los Potreros caldera floor, in the Los Humeros Volcanic Complex. This model predicts (1) the occurrence of few localized bulges in the otherwise not deformed caldera floor, and (2) that the faults corresponding to different bulges exhibit different spatial and temporal evolution. Already available field data from easily accessible outcrops and a simple morphological analysis show that these two conditions are not met at Los Potreros caldera. Also, a geothermal well (H4), located in the most recent supposed bulge for which Urbani et al. (2020) calculated an intrusion depth (Loma Blanca, intrusion depth of 425 ± 170 m), doesn't show any thermal and lithological evidence of such a shallow cryptodome. Finally, already published stratigraphic data and radiometric dating apparently disprove the proposed correlation between extruded viscous lavas and faulting. Thus, even if recent shallow intrusions may exist in the area, Urbani et al. (2020) fails to provide any useful information on their occurrence, location, age, emplacement depth, role in the resurgence of the Los Potreros caldera floor, and influence on the structure of the Los Humeros geothermal field.