Thermal history of the Acoculco geothermal system, eastern Mexico: Insights from numerical modeling and radiocarbon dating

摘要: Abstract Acoculco is a geothermal prospective area hosted by volcanic caldera complex in the eastern Trans-Mexican Volcanic Belt. Surface manifestations are scarce and consist of gas discharges (CO2-rich) acid-sulfate springs low temperature, whereas hydrothermal explosive activity profusely manifested meter-scale craters mounds debris breccias. Silicic alteration extends for several square kilometers around zone with features, affecting surficial rocks, primarily tuffs In subsurface, an argillic (ammonium illite) down to depth ∼ 600 m, underneath it propylitic (epidote–calcite–chlorite) occurs ∼ 1000 m. Thermal logs from exploratory borehole (EAC-1, drilled 1995 1810 m) showed conductive heat transfer regime under high gradient (∼ 140 °C/1000 m). contrast, thermal profile established temperatures homogenization fluid inclusions—measured on core samples same drill hole—suggests that convection occurred past through upper ~ 1400 m system. A drop permeability due precipitation minerals would have triggered cessation convective give place one. With purpose determining when transition occurred, we developed 1D model simulates time-depth distribution temperature. According our numerical simulations, this happened ca. 7000 years ago; date very recent compared lifespan addition, radiocarbon chronology indicates postdates end regime, having dated at least three events, 4867–5295, 1049–1417 543–709 y cal. BP. Therefore, explosions arise self-sealing system, involving natural hazard could affect future geothermal-power infrastructure.