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Hydrological Shifts in High-Altitude Volcanic Systems: Implications of permafrost thaw at Ojos-del-Salado (27°S)

Sebastián Ruiz-Pereira 1,2, Balázs Nagy2,3, Mirko Pavoni4, Jacopo Boaga4

  • Affiliations: 1DIHA, Pontificia Universidad Católica de Chile, Santiago, Chile 2PermaChile network, Földgömb Foundation, Budapest, Hungary 3Department of Physical Geography, Eötvös Loránd University, Budapest, Hungary 4Geophysics Department, Università di Padova, Padova, Italy.

  • Presentation type: Talk

  • Presentation time: Monday 15:00 - 15:15, Room R290

  • Programme No: 3.3.8

  • Theme 3 > Session 3

Abstract

Ojos-del-Salado, the world's highest volcano, presents a unique setting where post-volcanic heat and cryospheric processes converge, influencing surface and subsurface hydrology. Nevertheless, as permafrost thaws (as in Deception Island or the Klyuchevskaya volcano group, Kamchatka, Russia), there could be potential shifts toward deeper hydrological pathways, raising questions over hydrothermal mixing. This transition might not only occur in other volcanic regions but have given rise to the current groundwater background field from colder from paleoenvironments. Considering geothermal dynamics within post-volcanic landscapes, where asymmetrical energy outputs (e.g. localized high-enthalpy hydrothermal ponds), our aim is analyzing how (i) permafrost aggradation outlived geothermal subsurface dynamics, and (ii) how it might evolve into non-linear groundwater pathways thereon, and elsewhere. Our studies with the PermaChile network cover 12-year surface temperature records, and geophysical sub-soil characterizations to assess permafrost stability and distribution. Additionally, hydrogeological simulations assessed scenarios under downward and upward warming. Our findings evidenced sporadic permafrost at 5,200m ASL and a non-sporadic, 20-30 m-thick layer at 5,800m ASL. Unlike settings with persistent geothermal anomalies that might continuously thaw permafrost from below, the configuration appears to result from a heterogeneous energy budget, influencing thermal dynamics within the upper 10 meters of the massif above 5,000 m ASL. These findings contrast with conditions observed at Chajnantor volcano (23°S), where geothermal input restricts permafrost thickness, promoting higher confined aquifer transmissivity, and highlighting the significant hydrological impact of geothermal variability across high-altitude volcanic systems.